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diff --git a/78966-0.txt b/78966-0.txt new file mode 100644 index 0000000..2158f9f --- /dev/null +++ b/78966-0.txt @@ -0,0 +1,11639 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 78966 *** + + + + +[Illustration: HIPPOCRATES + +Ἢν γὰρ παρῇ φιλανθρωπίη πάρεστι καὶ φιλοτεχνίη. + +Where the love of man is, there also is love of this Art. + +Παραγγελίαι, i.e. _Precepts_ (Hippocratic Collection), § 6 + +] + + + + + A SHORT + HISTORY OF MEDICINE + + INTRODUCING MEDICAL PRINCIPLES TO + STUDENTS AND NON-MEDICAL READERS + + BY + + CHARLES SINGER + M.A., M.D., D.LITT., OXFORD + + FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS OF LONDON + LECTURER ON THE HISTORY OF MEDICINE + IN THE UNIVERSITY OF LONDON + + Scire potestates herbarum usumque medendi + Maluit et mutas agitare inglorius artes + + _It was his part to learn of the power of Medicine + and of the manner of healing and, heedless of + glory, to exercise that quiet art._ + Virgil, _Aeneid_ xii, 396-7 + + NEW YORK + OXFORD UNIVERSITY PRESS + AMERICAN BRANCH + 1928 + + + + + COPYRIGHT, 1928 + BY OXFORD UNIVERSITY PRESS + AMERICAN BRANCH + + + PRINTED IN THE UNITED STATES OF AMERICA + + + + +PREFACE + + +The position that Medical Science has now assumed in the social polity +demands that all educated men and women should have some knowledge +of the subject, whether they have had a medical training or no. In +these pages the author seeks to place before the reader, who is +without special knowledge, some account of Medicine as a Science. For +this purpose the historical method is peculiarly suited, since it +recapitulates, in some measure, the actual stages through which each +learner must pass. Though the story told here opens with Greek times, +the narrative of the earlier period is so condensed that more than +half the book is devoted to modern Medicine, which is presented as a +natural outgrowth of an ancient tradition. An attempt has been made to +keep the account as simple and as elementary as possible and to make +the smallest demands on the scientific equipment of the reader. The +slight divergence, in some matters, of the interests of American and of +English readers, has been held in mind, so that, it is hoped, the book +may be useful to both classes. + +Throughout the work two particular aims have been steadily kept in +view: first, to stress the principles of Medicine rather than the +details of practice; second, to treat of those principles in as small a +space as may be. For ‘principles’ the author has substituted at times +the word ‘Philosophy.’ He would, however, beseech the timid reader +to take no alarm at a word, for he employs the term ‘Philosophy’ in a +time-honored fashion, and he undertakes not to plunge deep into the +labyrinth of Metaphysic. The Philosophy of Medicine stands here for the +disinterested study of the theory of the subject, without reference to +its application to particular instances. + +Certain omissions in the book are justified by the author’s forthcoming +publication of a history of the biological sciences treated along +somewhat similar lines. It has thus, for example, seemed superfluous to +include here any but casual references to such highly important topics +as the study of hereditary characters or the experimental investigation +of developmental defects. It is, however, the duty of the author +to direct attention to certain other omissions necessitated by the +compression of the work into a small compass. The history of Medicine, +as here treated, is essentially a history of ideas. The personal +element has been kept wholly in the background and very little space +has been allotted to biographical matter. Nor do the limits of the book +permit any discussion of the status of medical men, and very little +even of their training. On this account many who in their day were +remarkable rather for the influence they exerted than for the advances +in knowledge which they initiated find no commemoration here. This line +of treatment has involved omission of reference to those teachers to +whom the author himself owes most, Sir William Osler and Sir Clifford +Allbutt. + +A work on Medicine must be colored, in some degree, by its author’s +conception of the nature of Life. On this theme there are divers views, +for the full discussion of which there is here no place. The author +professes himself, however, an adherent of a school of thought that is +not, at present, greatly in fashion. He ranges himself as a vitalist +under the banner of Aristotle and as a follower in the goodly company +of Harvey, Hunter and Virchow, of Claude Bernard and Johannes Müller. +He believes that there is a principle in living things that cannot +be expressed in chemical or physical terms. He believes that this +principle works to an intelligible end, that it is an _Entelechy_, an +indwelling purposiveness, and that it is as real a thing as anything +that is. + +_They are right who hold ‘soul’ to be not independent of body and yet +not a kind of body. ‘Soul’ is not body but something pertaining to the +body and dwelling therein, and, what is more, specific to each body. +Our forebears erred in seeking to fit the ‘soul’ into a body without +regard to the nature and qualities of the body, for the association +of ‘soul’ and body is by no means thus at random. And so indeed we +might expect, for the ‘Entelechy’ of each being comes naturally to be +developed in the potentiality of each being, that is to say in the +matter proper to it. Whence is manifest that the ‘soul’ is a certain +‘Entelechy’, a notion or form of that which has capacity to be endowed +with ‘soul’._ Aristotle, Περὶ Ψυχῆς, _II_, § 2. + +The author is well aware that this conception is neither useful +nor helpful for physiological research in the present state of our +knowledge. That is a very good reason for excluding it, as the vitalist +Claude Bernard excluded it, from the physiological laboratory. But +it is not a good reason for abandoning a point of view which does +something to make existence intelligible. On the contrary, turning from +the physiological laboratory to the living being as a whole, it is just +the indwelling purposiveness that is, before all things, most worthy of +consideration. Every function, every structure, every instinct, habit, +or reflex, every mental activity that is related to health--and which +is not?--may throw some light thereon. It appears to the author that +the scientific method is by far the mightiest weapon that has as yet +come within man’s grasp, for the illumination of these multitudinous +entities. The searching accuracy and power of that superb instrument, +wielded by human reason in the quest of human health, is the theme of +this volume. And yet, notwithstanding its triumphs, the experimental +method, as applied in the separate sciences, has, of its nature, +certain limitations with reference to living beings in general and +living human beings in particular. + +It is the business of each of the sciences--it is indeed an essential +part of the method of Science--to separate a circumscribed part of +the Universe for consideration in and for itself. Men of Science must +thus perforce become Chemists, Physicists, Astronomers, Botanists, +Cytologists, Statisticians, and the like. In this respect modern +_Science_ differs most profoundly from medieval _Scientia_ and from +ancient _Philosophia_. ‘Specialization’ follows modern _Science_ as +shadow follows substance. The new method has triumphed wonderfully in +these last centuries and it is mere folly and obscurantism to seek +to place intellectual stumbling-blocks in its path. Nor must we be +afraid of shadows. The author does plead, however, that, while the +Man of Science must, from the very nature of his method, cut off part +of his universe of experience from all other parts, he should bear in +mind, when not employed on his special task, that he has so cut off +and isolated his special experience, of deliberate and set intent. To +bear this fact in mind should not mean and must not mean that Science +fails to influence our view of the world as a whole, but it should +mean and must mean the basing of our view of the world as a whole on +experience as a whole, and not on an artificially separated fragment +of experience. For Man is neither a walking test-tube, nor a living +anatomy, nor a colony of cells, nor a self-repairing machine that +carries its own spare parts, nor a mere summation of the factors of +heredity and environment, nor, for that matter, is he a disembodied +spirit. But he is a being with a purpose. Of that purpose he, of his +nature, can know very little, since it is a part of that through which +he knows. Yet some glimpse of that purpose, though seen through a mist +and ever so dimly, we may perhaps gain from the view-point on which the +stony tracks of the separate sciences do ultimately converge. If the +separate sciences did not so conspire to one end, why should we ever +bother our heads or weary our limbs over their steep ascents? Are there +not rosier paths that we might tread? + +Throughout this book, then, the ideal kept in view is the description +of Medicine as a Rational Discipline involving many and perhaps all the +sciences. Medicine is not now and never has been followed wholly in the +scientific spirit. But it is the story of the scientific elements in +Medicine which is here to be told, and other aspects are passed over +with a silence which must not be interpreted as the silence of contempt. + +No two men undertaking the task here outlined would make quite the +same selections or allot emphasis in quite the same manner. Doubtless +the author has erred by omission and by commission, through ignorance +and through misconception, but he hopes that he has never erred +through prejudice. The ideas that he recounts are those that present +themselves to him as the most important and fruitful within the range +of scientific Medicine, and he is prepared to revise his opinions both +on matters of fact and on matters of stress. He will therefore be very +grateful for any corrections or suggestions. + +The number of names mentioned in the book has been reduced to the +utmost limit that has seemed feasible. In recounting many episodes +one name has often been taken as an example or type, and thus perhaps +sometimes an injustice has been done to other workers, no less +important but perhaps less typical. When modern times and living +persons are reached the selection becomes not only difficult but also +delicate, but the reader must remember that the names are not always +chosen for their eminence but sometimes rather as typifying the various +movements that have to be discussed. There is a further complication in +that an attempt is here made to bring history right up to date. Very +few names of living men are mentioned, though the work of many living +men is discussed. Though the author has sought to refrain from passing +any judgment on such latter-day conclusions the value of which does not +seem to him clearly and firmly established, yet even this course in +itself implies a judgment, and one in which he is even more likely to +err than in other topics of which the book treats. Nevertheless, some +such judgment seems necessary to make the book a coherent whole. + +There are several from whom the author has had help in the writing +of this book. Mrs. Singer has criticized every detail, and has +considerably modified its form. No English writer on the History of +Medicine can fail to refer to the great work of Lt.-Col. Fielding H. +Garrison of the United States Army and of the Library of Congress at +Washington. The author of this book owes much to Lt.-Col. Garrison’s +splendid bibliography, but even more to constant correspondence, +carried on now through a good many years, with the man who made it. +He owes a similar debt to a very old-standing friendship with Dr. E. +T. Withington of Oxford, to whom he takes the liberty of dedicating +this book. Professor Graham Wallas, Emeritus Professor of Sociology +in the University of London, and Professor J. C. Drummond, Professor +of Biochemistry in the University of London, have both read the book +in proof, and have made a number of suggestions and corrections. +Help on special points has been given by Dr. Clark-Kennedy of Corpus +Christi College, Cambridge, Dr. Raymond Crawfurd, Registrar of the +Royal College of Physicians of London, Dr. J. W. Eyre, Professor +of Bacteriology in the University of London, the Rev. Father J. R. +Fletcher, who has the unusual distinction of being both a Priest and +a Physician, Dr. K. Franklin of the Pharmacological Laboratory in the +University of Oxford, and Dr. William Robson, Lecturer in Law in the +University of London, as well as by the author’s pupils Dr. Ivor Hart, +Dr. J. F. Prendergast, Dr. Dorothy M. Turner and Mr. F. Prescott, M.Sc. +To all of these the author would tender his grateful thanks. + + CHARLES SINGER. + + UNIVERSITY COLLEGE, LONDON. _January_, 1928. + + + + +CONTENTS + + + PREFACE vii-xiv + + LIST OF ILLUSTRATIONS xix-xxiv + + I. ANCIENT GREECE, to about 300 B.C. + + § 1. Origins of Greek Medicine 1 + + § 2. The Hippocratic Physician 13 + + § 3. Hippocratic Practice 18 + + § 4. Aristotle 27 + + II. THE HEIRS OF GREECE, from about 300 B.C. to about A.D. 200 + + § 1. The Alexandrian School 36 + + § 2. Medical Teaching in the Roman Empire 41 + + § 3. Medical Services of the Roman Empire 45 + + § 4. Roman Hospitals 48 + + § 5. Galen 50 + + § 6. The Final Medical Synthesis of Antiquity 53 + + III. THE MIDDLE AGES, from about A.D. 200 to about A.D. 1500 + + § 1. The Period of Depression in Europe 61 + + § 2. Arabic Medicine 66 + + § 3. The Medieval Awakening 68 + + § 4. The Universities 70 + + § 5. Medieval Anatomy, Surgery, and Internal Medicine 72 + + § 6. Medieval Hospitals and Hygiene 77 + + IV. THE REBIRTH OF SCIENCE, from about 1500 to about 1700. + + § 1. The Anatomical Awakening 82 + + § 2. The Anatomical Reaction on Surgery 92 + + § 3. The Renaissance of Internal Medicine 95 + + § 4. The First Physical Synthesis 102 + + § 5. The Revival of Physiology 108 + + § 6. Microscopic Analysis of the Animal Body 115 + + § 7. From Alchemy to Chemistry 122 + + § 8. The Medical Theorists 126 + + V. THE PERIOD OF CONSOLIDATION, from about 1700 to about 1825. + + § 1. The Reign of Law 135 + + § 2. The Rise of Clinical Teaching 138 + + § 3. Physiology passes to the Modern Stage 142 + + § 4. Some Physiological Advances 145 + + § 5. Discovery of the Nature of the Air 151 + + § 6. Morbid Anatomy becomes a Science 156 + + § 7. Clinical Methods and Instruments 159 + + § 8. Surgery and Obstetrics 161 + + § 9. The Beginnings of the Science of Vital Statistics 166 + + § 10. Military, Naval, and Prison Medicine 169 + + § 11. The Industrial Revolution 172 + + § 12. Control and Recognition of Epidemic Diseases 182 + + VI. PERIOD OF SCIENTIFIC SUBDIVISION, from about 1825 onwards. + + § 1. Origins and Implications of Scientific Specialization 186 + + § 2. The Revolution in Preventive Medicine 192 + + (_a_) Preventive Medicine in Britain 193 + + (_b_) Preventive Medicine in U. S. A. 197 + + § 3. The Transition to a Physiological Synthesis 203 + + (_a_) Anatomy and Embryology in the Earlier Nineteenth Century 204 + + (_b_) Chemical Physiology in the Earlier Nineteenth Century 205 + + (_c_) Nervous Physiology in the Earlier Nineteenth Century 207 + + § 4. The Experimental Foundations of Modern Medicine 211 + + (_a_) The Work of Johannes Müller 211 + + (_b_) The Work of Claude Bernard 213 + + (_c_) The Work of Karl Ludwig 215 + + § 5. The Cell Theory and Cellular Pathology 219 + + § 6. Establishment of the Doctrine of the Germ Origin of Disease 224 + + § 7. Anaesthesia 235 + + § 8. The Revolution in Surgery 237 + + § 9. Some Modern Surgical Advances 243 + + § 10. Bacteriology becomes a Special Science 249 + + § 11. Some Important Bacteriological Results 253 + + § 12. The Study of Immunity 259 + + § 13. Some Practical Applications of Immunity 263 + + § 14. The Conquest of the Tropics 271 + + (_a_) Yellow Fever 273 + + (_b_) Malaria 280 + + § 15. The Changed View of Insanity 286 + + § 16. The New Movement in Psychology 293 + + § 17. The Revolution in Nursing 295 + + § 18. Some Modern Physiological Concepts of Clinical Import 301 + + (_a_) Ductless Glands and Internal Secretions 302 + + (_b_) Nervous Integration 308 + + (_c_) Vitamins 311 + + § 19. Knowledge of the Eye and its Disorders 313 + + § 20. Investigation of the Nature and Action of Drugs 322 + + (_a_) Entry of Vegetable Drugs into the Pharmacopoeia 322 + + (_b_) Active Principles 323 + + (_c_) The Alkaloids 325 + + (_d_) The Glucosides 327 + + (_e_) The Study of Pharmacology 328 + + (_f_) Chemotherapy 329 + + § 21. Interpretation of Collective Medical Data 333 + + EPILOGUE 351 + + INDEX 364 + + + + +LIST OF ILLUSTRATIONS + + + 1. Hippocrates. British Museum, second or third + century B.C. _Frontispiece_ + + 2. Ivory and gold Minoan statuette of a votaress in a + state of ecstasy. By kind permission of the Museum + of Fine Arts, Boston, U.S.A. 5 + + 3. Surgical instruments recovered from Babylonian + sites. Reproduced by kind permission of Professor + Meyer-Steineg of Jena 5 + + 4. Clay model of sheep’s liver used for instruction in + divination in a Babylonian temple school. Drawn + from the object in the British Museum 6 + + 5. Imhotep. From a statuette in the British Museum 8 + + 6. Aesculapius. Photograph Anderson 8 + + 7. Scheme illustrating some of the sources of + Hippocratic Medicine 9 + + 8. A Greek clinic of about 400 B.C. From a vase + painting 17 + + 9. Instruments used by Greek surgeons 20 + + 10. The _Ladder of Nature_ according to Aristotle 28 + + 11. The womb with the names of its parts as given by + Aristotle 29 + + 12. Embryo dogfish, _Mustelus laevis_, after Johannes + Müller 29 + + 13. The four _Elements_ in association with the four + _Humours_ and the four _Qualities_ 34 + + 14. Inscribed tablet of about 100 B.C. from the wall of + the temple of Kom-Ombos in Upper Egypt 40 + + 15. Roman surgical instruments of the first century + A.D. found at Pompeii 44 + + 16. Aqueduct of Nero from an engraving by Piranesi 47 + + 17. Roman advanced dressing-station. From Trajan’s + column 48 + + 18. Island of St. Bartholomew in the Tiber at Rome. + From an engraving by Piranesi 51 + + 19. Dissection of the hand of a man 57 + + 20. Dissection of the hand of a Barbary ape 57 + + 21. Galen’s Physiological System 59 + + 22. The earliest known representation of St. Luke as a + Physician 63 + + 23. Picture of Trephining, from a thirteenth-century + manuscript 63 + + 24. Illustrating the mode of action of the trephining + instrument used by the surgeon in Fig. 23 64 + + 25. Scene at a siege of Salerno, from a manuscript + prepared in South Italy early in the thirteenth + century 65 + + 26. A Jewish translator receiving an Arabic medical + volume from an Eastern potentate (right) and + handing it, translated into Latin, to a Western + monarch (left) 69 + + 27. Medieval Bologna, from a mural painting of about + 1500 in the town-hall of the city 73 + + 28. An anatomical lecture at Padua in the fifteenth + century, from a contemporary Italian woodcut 75 + + 29. A ward in a hospital at Paris in the sixteenth + century. Reproduced, by kind permission of M. + Édouard Champion, from D. L. MacKay, _Les hôpitaux + et la Charité à Paris au XIII^e siècle_ 79 + + 30. Drawing of Dissection of the Heart by Leonardo da + Vinci 85 + + 31. Title-page of the work _On the Fabric of the Human + Body_, by Vesalius, published in 1543 87 + + 32. Skeleton from the anatomical work of Vesalius 91 + + 33. Artificial arms and hands, designed and figured by + Ambroise Paré 93 + + 34. The ‘Four Temperaments’, from the Guild Book of the + Barber-Surgeons of York 97 + + 35. Earliest picture showing the use of Tobacco 99 + + 36. Allegorical picture illustrating the venereal + plague 101 + + 37. Sanctorius in his balance 107 + + 38. The principle of Galileo’s thermometer 109 + + 39. The application of the system shown in Fig. 38 by + Sanctorius, who used a curved tube 109 + + 40. The adaptation of the instrument, shown in Fig. 39, + as a clinical thermometer 109 + + 41. Galileo’s ‘pulsimeter’ 109 + + 42. Dissection of a vein in the thigh and leg, from + Fabricius 111 + + 43. The circulation of the blood 113 + + 44. The superficial veins, from William Harvey 114 + + 45. Lungs of a frog, showing the capillary vessels, + from Malpighi 116 + + 46-9. Stages in the formation of the chick, from Malpighi + 117 + + 49a. One of Leeuwenhoek’s microscopes. Reproduced, by + the permission of Mrs. George Martin, from _The + Asclepiad_, II 118 + + 50-3. Illustrating the blood corpuscles and circulation + after Leeuwenhoek 119 + + 54. The first representation of Bacteria 120 + + 55-56a. Drawings by Leeuwenhoek of the structure of + muscle 121 + + 57-60. Experiments by Swammerdam 123 + + 61. Boyle’s Air-pump 125 + + 62. Descartes’ conception of the relation of a sensory + impression and a motor impulse 128 + + 63. Diagram of Descartes, to illustrate nervous action + 129 + + 64. Diagrams from Borelli, to illustrate movements of + muscles 130 + + 65. Diagram of muscular action 131 + + 66. Two Plates from Bernard Siegfried Albinus’ + _Anatomical Plates of the Muscles of Man_, Leyden, 1747 141 + + 67. Windmill ventilator designed by the Rev. Stephen + Hales. From a print in the British Museum 147 + + 68-70. Experiments illustrating the effects of metallic + contacts on the nerves and muscles of frogs’ legs. + From A. Galvani, _On Electric Forces_, 1792 149 + + 71-3. Volta’s figures of the electric pile and crown of + cups 150 + + 74-5. Illustrating the chemistry of burning and + breathing, from a work issued by Mayow in 1674 152 + + 76. Apparatus from Joseph Priestley’s _Experiments and + Observations on different Kinds of Air_, 1774 154 + + 77. Lavoisier in his laboratory making experiments on + breathing. From a contemporary sketch 155 + + 78. Part of the lung of Dr. Samuel Johnson, from a + drawing published by Matthew Baillie 158 + + 79-82. Laënnec’s wooden stethoscope, from the first + edition of his work _On Instrumental Auscultation_ + 161 + + 83. Lying-in scene in the sixteenth century, from a + contemporary work on Midwifery 163 + + 84-6. Early obstetric instruments 164 + + 87. John Hunter’s country house at Earl’s Court, + Kensington, before its demolition in 1886. + Reproduced, by the kind permission of Mrs. George + Martin, from _The Asclepiad_, VIII 165 + + 88. An eighteenth-century Quarantine station (Naples) + 173 + + 89-90. Illustrating the textile trade from home industry + to factory work with the consequent break-up of the + family as the labour unit. The upper picture from a + drawing by George Walker, the lower from _Economic + Botany: The Cotton Manufacture_ 175 + + 91. Graph showing approximate growth of population in + England and Wales 1670-1830 176 + + 91a. Tables illustrating vital conditions in the + eighteenth century 177 + + 92. St. Bartholomew’s Hospital at Smithfield, London, + in 1720. From Strype’s edition of Stow’s _Survey_ + 179 + + 93. The Pest House in Tothill Fields, London, in 1796. + From a print in the British Museum 181 + + 94. Hand of Dairymaid infected with cow-pox, from + figure by Jenner 184 + + 95. A cartoon by Robert Cruikshank 191 + + 96. Annual death-rate in London per thousand living + over 85 years 196 + + 97. The Old _Dreadnought_ Hospital Ship 199 + + 98. Diagram of Transverse section of the Spinal Cord, + &c. 208 + + 99. Diagram to illustrate Reflex 209 + + 100. Diagram to illustrate Cerebral localization 210 + + 101. Thomas Young’s Kymograph 217 + + 102-5. Drawings by Theodor Schwann to illustrate cells + 221 + + 106. Organisms of Fermentation, from Pasteur 226 + + 107. Pasteur’s experiment to prove that fermentation is + the result of air-borne organisms 228 + + 108. Bacilli of Anthrax 231 + + 108a. Screw used in the eighteenth and the early + nineteenth century to secure analgesia. Reproduced, + by the kind permission of Mrs. George Martin, from + _The Asclepiad_, VII 236 + + 109. The ‘Donkey Engine’ designed by Lord Lister. Now in + the Royal College of Surgeons of England 241 + + 109a. Operating table used by Lord Lister in the Glasgow + Royal Infirmary. Reproduced, by kind permission of + Messrs. Jackson, Wylie & Co., from _Lister and the + Lister Ward in the Royal Infirmary of Glasgow_ 242 + + 110. ‘Spencer Wells Forceps’ 244 + + 111. Spencer Wells performing an abdominal operation + 245 + + 112. An operation in the sixteenth century 246 + + 113. An abdominal operation under modern conditions. + Reproduced, by kind permission of W. B. Saunders’ + Company, Philadelphia, from _The Operating Room, + St. Mary’s Hospital, Rochester, Minnesota_ 247 + + 114. Bacilli of Diphtheria 254 + + 115. Bacilli of Plague 255 + + 116. Diagram showing the Incidence of Malta fever 256 + + 117. Bacilli of Tetanus 257 + + 118. Bacilli of Typhoid Fever 258 + + 119. Death-rate of cases of Laryngeal Diphtheria 263 + + 120-1. A common Malaria-carrying mosquito and a Yellow + Fever-carrying mosquito. Reproduced, by kind + permission of the British Museum (Natural History), + from Edwards, _Mosquitoes and their Relation to + Disease_ 272 + + 122. Distribution of Malaria in England and Wales 281 + + 123. The Life-History of the Parasite of Malaria. + Reproduced, by kind permission of Messrs. + Baillière, Tindall & Cox, from C. M. Wenyon’s + _Protozoology_, vol. II 285 + + 124-5. A Malaria-carrying mosquito and a common gnat. + Reproduced, by kind permission of the British + Museum (Natural History), from Edwards, _Mosquitoes + and their Relation to Disease_ 287 + + 126. Chart of cases of Malaria reported in Italy in + recent years 287 + + 127. ‘The Retreat’ near York. Reproduced, by permission + of Messrs. Kegan Paul, Trench, Trubner & Co., from + Tuke, _Chapters in the History of the Insane in the + British Isles_, 1882 289 + + 128. Florence Nightingale at Scutari. Photograph, + Rischgitz Collection 299 + + 129-30. Cretinous infant before and after thyroid + treatment. Reproduced by kind permission of the + Royal College of Surgeons 305 + + 131. Diagram to show the structure of the eye 314 + + 132. Diagram to show the nature of accommodation of the + eye 317 + + 133. The Organisms of Syphilis in a smear from the Local + Infection 331 + + 134. Diagram illustrating alteration in Age-distribution + of the population of England and Wales. Reproduced, + by kind permission of the authors, from + Carr-Saunders & Caradog Jones, _Social Structure of + England and Wales_ (Clarendon Press) 335 + + 135. Death-rate from Cancer of the Tongue. Reproduced, + by kind permission of the Editors, from _The + Quarterly journal of Medicine_, vol. v, No. 5 337 + + 136. Death-rate from Cancer of the Lip. Reproduced, by + kind permission of the Editors, from _The Quarterly + Journal of Medicine_, vol. v, No. 5 338 + + 137. Death-rate from Cerebral Haemorrhage. Reproduced, + by kind permission of the Editors, from _The + Quarterly Journal of Medicine_, vol. v, No. 5 340 + + 138. Curve showing percentage of deaths from Phthisis to + total deaths 343 + + 139. The normal curve of error 345 + + 140. Curve of monthly number of deaths from Small-pox + during an epidemic at Warrington, Lancashire, in 1743 346 + + 141. Curve of weekly number of cases of Scarlet Fever + during an epidemic at Glasgow in 1892 346 + + 142. Analysis of curve representing death-rates from + Summer Diarrhoea in London over a long period of + years 347 + + + + +I + +ANCIENT GREECE + +(TO ABOUT 300 B.C.) + + +§ 1. _Origins of Greek Medicine._ + +Scientific Medicine began with the Greeks. The Greeks not only started +scientific Medicine upon its course, but also provided the substantial +basic elements of our anatomy, physiology and pathology, and above +all, perhaps, our conception of the bodily ‘constitution’, ‘habit’ or +‘temperament’. It is from the Greeks that we derive almost all our +medical nomenclature. When to this we add that our medical traditions +are inherited through a direct and continuous chain from the Greek +practitioners, it becomes evident that the debt that Medicine owes to +this marvellous people is great indeed. + +Now this debt has become associated with two or three great figures. +The names Hippocrates, Aristotle, Galen, are familiar to all. Yet it is +not always recognized that these men were but the representatives of a +widely extended and long-lasting system. Greek Medicine was, in fact, +like modern Medicine, the result of centuries of carefully recorded, +collated and progressive research. Greek Medicine first assumed a +scientific aspect with the Ionian and Italo-Greek philosophers at the +very beginning of the sixth century B.C. It continued to make important +advances until the death of Galen at the very end of the second century +of the Christian era. Thus the life-span of progressive and scientific +Medicine among the Greeks was no less than eight hundred years. With +the most tolerant use of the words ‘scientific’ and ‘progressive’, +we can hardly place the beginnings of modern Medicine in Europe +before the end of the fifteenth century. Thus our own system has only +been developing its characteristic features for some four and a half +centuries, which is but little more than half the course that Greek +science ran. + +It is evident, therefore, that we may have much to learn from the +Greeks, not indeed in matters of actual fact or observation--for nearly +all that is _directly_ useful in their writings has been absorbed long +ago into our medical literature--but in spirit and method. From a +study of the character and course of Greek medical science we can gain +hints of the snares and pitfalls and catastrophes into which the Art +of Medicine may at times be led. Further, by study of the practice of +Medicine under conditions so different from ours, we learn something +of what is truly permanent in the Art of Healing. Lastly, by tracing +the growth of the Science of Medicine, as it arose among the Greeks and +as it died in the hands of their less worthy descendants, we may take +alike example and warning. We may learn to distinguish the healthy and +vigorous growth of a science from the stunted and deformed products +that are often acclaimed, even in our own times, as Wisdom’s final word +to Man. + +It has been said that, ‘save the blind forces of Nature, nothing lives +or moves which is not Greek in origin’. The saying needs modification, +for there is a thing which still lives and moves that is not Greek in +origin, a blind force which is not a blind force of Nature. It is the +force of Superstition, of that age-old belief that Nature will give +us something for nothing, which is expressed by the word ‘Magic’. +The Greeks were no more free from that contemptible fallacy than +are the men of our own days. But the greatest of the Greeks stood +wholly above such folly, and we can watch the Greek mind gradually +lifting itself from that primeval mental attitude which is older than +any known culture, older perhaps than any known race, the attitude +of Nature-Worship, or ‘Animism’. To give an idea of how the ‘sweet +reasonableness’ of the Greek mind gradually dissipated the animistic +fog, a few words must be said about the history of the Greeks. Without +that amount of history it would seem a miracle that Man ever became +reasonable at all. + +The Medicine we call Greek might be described as the system which +prevailed in ancient times in that half of the Mediterranean area which +lies east and south of the Italian Peninsula. + +Up to about 1000 B.C. most of the coast-lands of this Mediterranean +area were inhabited by that very remarkable people, the Minoans. +These have left some extraordinary remains, the full significance +of which has not yet been revealed. The general development of the +Minoan civilization has, however, been clearly outlined by modern +archaeological investigation. This has resulted in an entirely new +interpretation of the story which Homer tells in the _Iliad_. The siege +of Troy represents an attack by the invading Greeks on one of the last +Minoan strongholds. About 1000 B.C. the whole Eastern Mediterranean +basin was being overrun by the Greek tribes coming in from the north. +These Greeks were no pure race, but a mixed multitude of invaders +who came along several lines of advance. As always happens in such +invasions, the conquered were not exterminated, but mingled with the +invaders. Thus the Greeks, as they advanced, absorbed much of the +culture and outlook of the civilization that they submerged. + +In considering the history of Rational Medicine we are concerned +chiefly with two main invading streams of Greek tribes: that of the +Dorians, who passed towards Crete and towards the Island of Cos and the +opposite peninsula of Cnidus, and that of the Ionians, who colonized +most of the remaining part of western Asia Minor. These two peoples +were, between them, responsible for the main intellectual output of the +Greeks of those early days. The medical system which they initiated +first took shape in western Asia Minor, and thence became diffused over +the whole of the Greek world. The Greek system of Medicine which thus +arose in Asia Minor had various roots, as indeed the Medicine of a +mixed people, living under very complex social conditions, was bound to +have. + +Firstly, there was the submerged civilization of the conquered Minoan +folk. It is probable that the cult of the serpent--so constantly +associated with Aesculapius and still used as a medical emblem--was of +Minoan origin, for the serpent was a symbol much used in the Minoan +religion (Fig. 2). It is probable too that some of the hygienic ideas +of the Greeks were derived from the same source, for the Minoans had an +excellent system of drainage. We can, however, say little on this head +because the interpretation of the Minoan records is still hidden from +us. + +[Illustration: + +FIG. 2. IVORY AND GOLD MINOAN STATUETTE of a votaress in a state +of ecstasy. In either hand she holds a serpent, illustrating the +importance attached to this animal in the Minoan cult. From the Museum +of Fine Arts, Boston, U.S.A. + +FIG. 3. SURGICAL INSTRUMENTS recovered from Babylonian sites. There are +here represented three knives, a saw and a trephine. These instruments, +which illustrate the state of surgery in the ancient Mesopotamian +civilization, are in the possession of Professor Meyer-Steineg of Jena, +by whose permission they are here reproduced. + +] + +Secondly, we have to remember that the shores of Asia Minor lie on the +outskirts of the great civilization which had grown up in the valley +of the Tigris and the Euphrates. The Greeks drew from that source much +of their more superstitious beliefs, as well as some, at least, of +their scientific method. On the one hand, the demoniac theories that +bulk so largely in later Greek medicine doubtless came from Assyria +and Babylonia. The Medicine of the New Testament, for instance, with +its casting out of devils, is of Mesopotamian origin. But, on the +other hand, the Mesopotamian peoples had for long ages laid up a great +treasury of observation, notably of astronomical data which were +often applied to astrological ends. There was also some knowledge of +anatomy derived from the entrails of animals used in divination (Fig. +4). Working on the basis of these records, the Greeks were able to +erect a scientific method which appears as a prominent feature in +their intellectual life in later centuries. Moreover, there was in +Mesopotamia a standardization of both medical and surgical procedure +which the nimble-witted Greeks were quick to adopt (Fig. 3). On its +lower and less intelligent side, however, the Mesopotamian material was +made to minister to Greek superstition and especially to astrological +belief. + +[Illustration: + +FIG. 4. CLAY MODEL OF SHEEP’S LIVER used for instruction in divination +in a Babylonian temple school. The object is now in the British Museum. +It is covered with cuneiform writing, the nature and contents of which +fix its date as about 2000 B.C. The writing is here omitted for the +sake of simplicity. + +Various parts of the liver have their Babylonian technical terms and +can be identified with parts recognized by modern anatomists. Some of +these modern terms are written on our drawing. + +To each hole in the original model an inscription containing a forecast +is assigned. The diviner made his forecast by comparing an actual +liver with this clay model at each point corresponding to a hole. His +forecast was elaborated according to the state of the liver at all +these points. + +] + +Thirdly, to the Egyptian civilization the Greek debt was also +considerable. Many drugs were derived from Egypt and others were +suggested by Egyptian practice. The basis of Greek medical ethics, +too, can be traced to Egypt. Some of the practical devices of Greek +Medicine, such as the forms of the surgical instruments, were of +Egyptian origin. Nor can we neglect the statement made by the Greeks +themselves, that mathematical knowledge--the test and index of all +scientific growth--came to them first from Egypt. Lastly, we note that +the Egyptians deified a physician, Imhotep (Fig. 5), in exactly the +way that the Greeks deified their physician Aesculapius (Fig. 6). Both +Imhotep and Aesculapius were, in fact, historic personages, and their +evolution into gods presents many interesting parallels. + +[Illustration: + +FIG. 5. IMHOTEP, originally a physician, subsequently deified as an +Egyptian god of Medicine. From a statuette in the British Museum. + +FIG. 6. AESCULAPIUS, originally a physician, subsequently deified as a +Greek god of Medicine. He holds a staff, around which a serpent twines. +From a statue in the Capitoline Museum at Rome. + +] + +The Greeks of western Asia Minor, thus drawing material from many +sources, came to develop, towards the end of the seventh century B.C., +a philosophical system from which the whole of their Science may be +said to be a natural growth. Factors in this development were the +medical schools of Cos, where Hippocrates was born, and of the opposite +peninsula, Cnidus. These schools were in active operation by the sixth +century B.C. By the middle of the fifth century they were important +elements in the growing complexity of Greek life. Much of the so-called +_Hippocratic Collection_, which contains the earliest Greek medical +writings that have survived, must have been put together somewhere in +the fourth century B.C., though its final recension is certainly later +(Fig. 7). In that final recension Persian and Indian elements were also +included, though to what degree is still very uncertain. + +[Illustration: FIG. 7. SCHEME ILLUSTRATING SOME OF THE SOURCES OF +HIPPOCRATIC MEDICINE] + +But the picture of the development of Greek Medicine is not yet +complete. Although we inherit the scientific spirit from the Greeks, +and although they set a standard for all time of the purest and +most disinterested type of medical practice, they are also in part +responsible for some of the basest forms of medical jugglery that have +afflicted and still afflict mankind. The medicine of the physicians was +only one of their medical systems. There was a far lower form which +gradually passed into the hands of the priests. The temple jugglery of +Greece is ancestor, both by imitation and by direct tradition, of much +medieval and modern medical miracle-mongering. + +Furthermore, in ancient as in modern times, all medical men were not +equally pure in aim or scientific in method. The practice of some Greek +physicians was more than flavored with magic. In justice, also, it +must be said that not all priests were mere charlatans, and that there +are traces of scientific method in the treatment of patients in the +temples. There was, indeed, a relation between the practice of some +of the physicians among the Greeks and that of some of their priestly +magicians. We shall not attempt to determine the actual extent and +nature of this relationship. For our purpose it is enough that the two +systems were quite distinct in their most typical developments. + +The temple system of Greek Medicine was associated from an early date +with a deity, Asklepios, or, to give him his better-known Latin name, +Aesculapius. Numerous representations of him have come down to us, and +in them we see him gradually molded to a particular type. He becomes at +last an aged man of noble, benevolent and dreamy aspect, holding in +his hand a staff around which a serpent twines (Fig. 6). The cult of +the god Aesculapius was carried on at numerous sites. The best known, +both from literature and excavation, is Epidaurus. The conditions there +are typical of those in other Aesculapian centers. + +Epidaurus is about thirty miles from Athens. It lies between two +considerable ranges of hills, and the country bears still, in its +customs and place-names, some remnants of the ancient cult. One +tradition tells that a certain maiden, Koronis, being with child by +Apollo, brought forth the infant Aesculapius on the mountain above +Epidaurus. There is still a village named Koroni hard by. She fled +to conceal her shame and left the child on the mountain, where it +was tended by a goat and watched over by a dog. The infant performed +various miracles which we need not pursue, though the temple arose on +the site where he is said to have wrought them. One of his miracles, +however, has a wider interest and is worth recounting. A certain +Hippolytus, falsely accused of impure relations with his stepmother, +was slain by the gods in answer to the curses of his father, Theseus. +Raised from the dead by the wonder-working Aesculapius, he reappears in +legend at the Arician grove in Italy. ‘There’, says a Greek chronicler +of the second century A.D., ‘he became a king and devoted a precinct +to Artemis, where, down to my time, the prize for the victor in single +combat was the priesthood of the goddess. The contest was open to no +freeman, but only to runaway slaves.’ + +The son slain by his father and then rising from the dead; the runaway +slave seeking sanctuary with Artemis in her grove, allowed his liberty +and elevated to the priesthood there; the priesthood held only so long +as the priest can guard it in mortal combat against the next runaway +slave; this succession of slave kings and priestly murders has touched +the imagination of the poets and artists in ancient and in modern +times. The sacred grove of Artemis stood by the side of the lake of +Nemi: + + The still glassy lake that sleeps + Beneath Aricia’s trees-- + Those trees in whose dim shadow + The ghastly priest doth reign, + The priest who slew the slayer + And shall himself be slain. + +It is a picture utterly out of accord with the general trend of +classical mythology. Long ago scholars saw therein a remnant of a +submerged faith, that ancient ‘Nature worship’ which survived among the +Greeks, and survives with us. From this incident is named the great +classical work of Anthropology, _The Golden Bough_. By this story and +by all that it implies, by all that learning has drawn out of it and +associated with it, the history of Medicine comes into contact with the +brooding spirit of savage man. Into that dark realm we shall not enter +in this volume. + +History is the tale of the spirit of Man unfolding itself. This process +is always slow, often imperceptible, sometimes retrograde, yet over +long periods of time it is sure. Where no evolution of the spirit can +be traced true history cannot be written, wherefore no man can write a +history of human folly. Irrational man, driven by disease and fear of +death, exhibits the same follies in all ages. The medical follies and +superstitions of our own days are as in those when Aesculapius claimed +men’s allegiance. His garments and his names are changed, his temples +are transformed, his priests assume other titles, but his face is the +same, and he works the same wonders with about the same frequency. It +is of Rational Medicine that we have henceforth to speak. + + +§ 2. _The Hippocratic Physician._ + +We turn to the other side of the picture. Nothing could be in greater +contrast to the orgies of the savage, the dark ways of the magician, +or the charlatanry of the priests, than the serene spirit of wisdom +which pervades the best Greek Medicine. The finest presentation of that +system is to be found in a group of about a hundred works that have +been associated together since antiquity under the name of Hippocrates. +It is known as the _Hippocratic Collection_. + +It will naturally be asked, ‘Which of these works is by the man whose +name they bear?’ To that question, alas, no definite answer can be +given. There is no single work which we can state with certainty to +be the composition of the Father of Medicine. The books of which the +_Collection_ is composed are the work of a number of authors, belonging +to different schools, holding various and often contradictory views, +living in widely separated parts of the Greek world and writing at +dates divided from each other, in the most extreme cases, by perhaps +five or six centuries. Of the finest books of this collection we can +but say that they contain nothing inconsistent with a Hippocratic +origin, that their ethical standpoint is in accord with the Hippocratic +ideal, and that they are the work of physicians of great intellectual +power and experience. + +If we ask what is known about Hippocrates himself, and if we seek +information rather than entertainment, our answer will be almost as +meager. Hippocrates is no mythical figure, for he is mentioned with +high respect by his younger contemporary, Plato. He was the son of a +physician, and was born at Cos about 460 B.C. The most active period +of his life thus began about 420 B.C. His death is placed between 377 +and 359--the latter would make him 101, an appropriate age for a great +physician. He led a wandering life, and is heard of at Cos, Thasos, +Athens, in Thrace and elsewhere, and lastly in Thessaly, where his +grave was long shown. Among his pupils were his two sons, and his +son-in-law. Of the work of the latter we have a fragment preserved both +by Aristotle and in the _Hippocratic Collection_ itself. + +That is all that is known about the Father of Medicine. We have not +even his portrait. Yet we have something far better; we have an +idealized representation of what the Greek would wish his physician +to be. It is a noble bust to which the name of Hippocrates was early +attached. Many copies exist (see Frontispiece). The calm, righteous +and dignified presence which it portrays has stamped itself on the +consciousness and conscience of those who follow the Art of Healing. To +that gracious figure the medical man will continue to pay homage. + +If critical examination has dealt thus hardly with the Hippocratic +writings and with Hippocrates himself, what has been left which we +may surely derive from the Greek medical system? The answer is that +Medicine has from the Greeks two great things: the picture of a man and +the institution of a method. + +The man is Hippocrates himself. His figure, gaining in dignity what it +loses in clearness, stands for all time as that of the ideal physician, +for the ideal is there and is clearly set forth in these great +writings, whether we discern the details of his earthly features or no. +Calm and effective, humane and observant, prompt and cautious, at once +learned and willing to learn, eager alike to get and give knowledge, +unmoved save by the fear lest his knowledge may fail to benefit +others--both the sick and their servants the physicians,--incorruptible +and pure in mind and body, the figure of the greatest of physicians has +gained, not lost, by time. In all ages he has been held by medical men +in a reverence comparable only to that which has been felt towards the +founders of the great religions by their followers. The figure of the +Hippocratic physician has been of incalculable spiritual value to the +medical profession in the twenty-three centuries that have passed since +his death. + +So much for the man. We turn now to the method. + +The _method_ of Hippocratic medicine is that known to-day as the +_experimental_ or better _experiential_. It was employed among the +Greeks for centuries after the death of Hippocrates. Then came a +time when a social and philosophical upheaval prevented its further +prosecution. For the thousand years that followed the break-up of the +Roman Empire the medical practice of Europe was at best a corrupted +imitation and misunderstanding of the Hippocratic teaching; at worst +it descended to a low level of Animism and Magic. Then there was a +rally. Slowly--very slowly at first--the foundations of Modern Science +were laboriously laid. Among the first elements in this scientific +Renaissance was the recovery of the Hippocratic works. + +In the centuries that followed this Renaissance the very words of the +_Hippocratic Collection_ were taught in the medical schools in a spirit +that was anything but that of Hippocrates. Gradually, however, a better +understanding crept into men’s minds. The spirit of those writings and +their methods and observations came now rightly to be exalted above +the works themselves. The works themselves were wisely dropped from +the medical curriculum. They are no longer used in any medical school. +But if we turn again to contemplate the Hippocratic treatises, we may +recognize in them the modern process of careful record of data and +cautious inference from them--that collation of experience from various +sources obtained by various methods with which we are now so familiar. +We may even see in full force the actual process of case-taking, bed +side instruction and clinical lecture. These methods are practised +much in the way in which we know them, and are set forth with a +conciseness and beauty of language and a loftiness of ethical tone +which have not since been surpassed. To such a collection medical men +must always return. No part of it is more impressive than the so-called +_Hippocratic Oath_. + +[Illustration: FIG. 8. A GREEK CLINIC OF ABOUT 400 B.C., when +Hippocrates was in his prime. From a vase painting. + +The physician sits in the center. He holds a lancet in his right +hand, seizes the patient’s right arm with his left and is bleeding +him from a vein at the bend of the elbow. The blood falls into a +large basin on the floor. Above the physician’s head are suspended +three cupping vessels, shaped thus: + +[Illustration] + +To the right sits a patient awaiting his turn to interview the +physician. His left arm is bandaged. Behind this patient stands a +figure smelling a flower as a preventive against infection. Behind the +physician stands a man wounded in the left leg, which is bandaged. +Back to back to this last figure is a dwarf with a disproportionately +large head. His body exhibits deformities typical of the developmental +disease now known as _Achondroplasia_. In addition to his other +deformities, we note that his muscular body is hairy, and that the +bridge of his nose is sunken. On his back he carries a hare which is +almost as tall as himself. Talking to the dwarf is a man leaning on a +long staff, who has the remains of a bandage round his chest.] + +The _Hippocratic Oath_, in its present form, is of very much later date +than Hippocrates. Yet parts of it may be even earlier than he, and +some suggestion of the Oath is, perhaps, to be seen in the contents of +Egyptian papyri of the second millennium B.C. It need hardly be said +that the late date of the _Oath_ by no means removes the interest of +this grand ethical monument. No passage better reflects the spirit of +the Hippocratic physicians. The oath is clearly designed for a youth +entering on his apprenticeship to such a one. + + ‘I swear by Apollo the healer, invoking all the gods and + goddesses to be my witnesses, that I will fulfil this Oath and + this written Covenant to the best of my ability and judgement. + + ‘I will look upon him who shall have taught me this Art even as + one of my own parents. I will share my substance with him, and + I will supply his necessities, if he be in need. I will regard + his offspring even as my own brethren, and I will teach them + this Art, if they would learn it, without fee or covenant. I + will impart this Art by precept, by lecture and by every mode + of teaching, not only to my own sons but to the sons of him who + has taught me, and to disciples bound by covenant and oath, + according to the Law of Medicine. + + ‘The regimen I adopt shall be for the benefit of the patients + according to my ability and judgement, and not for their hurt + or for any wrong. I will give no deadly drug to any, though + it be asked of me, nor will I counsel such, and especially I + will not aid a woman to procure abortion. Whatsoever house I + enter, there will I go for the benefit of the sick, refraining + from all wrongdoing or corruption, and especially from any act + of seduction, of male or female, of bond or free. Whatsoever + things I see or hear concerning the life of men, in my + attendance on the sick or even apart therefrom, which ought not + to be noised abroad, I will keep silence thereon, counting such + things to be as sacred secrets. Pure and holy will I keep my + Life and my Art. + + ‘If I fulfil this Oath and confound it not, be it mine to enjoy + Life and Art alike, with good repute among all men at all + times. If I transgress and violate my oath, may the reverse be + my lot.’ + + +§ 3. _Hippocratic Practice._ + +Among the most remarkable features of the _Hippocratic Collection_ is +the feeling of contact with the patient which most of its works convey. +This is naturally a special characteristic of the surgical works. One +treatise, which bears the title _On wounds of the head_, has always +drawn attention as bespeaking especial ingenuity and experience. The +description of trephining is of peculiar interest, because the practice +was known in prehistoric times and is still employed by savage and +semi-civilized peoples. The process recommended for cases of fracture +of the skull and injury to the underlying structures resembles, in +many details, the modern surgical procedure. + + ‘When it is necessary to trephine a patient, make up your + mind and judge as follows. If you have had charge of the case + from the first, do not trephine the bone down to the membrane + at once, for it is not desirable that the membrane be long + exposed, lest it end by becoming rotten and fungous. There is + also another danger, to wit that you wound the membrane with + the saw during the operation, if you try to remove the bone by + trephining immediately down to the membrane. Therefore, when + the bone is almost sawn through and is already loose, cease + trephining and allow the bone to come away of itself. While + trephining, often remove the instrument and dip it in cold + water. If you do not do this, the trephine, becoming heated by + the circular motion and heating and drying the bone, may burn + it and cause an unduly large piece of the bone round the sawing + to come away.’ + +[Illustration: FIG. 9. INSTRUMENTS USED BY GREEK SURGEONS. + +_a_ Simplest form of trephine. It has central pin and serrated edge. +The point is held against the skull and the staff twirled between +the hands. (Cf. Fig. 112.) It could also be rotated by a crosspiece +and thong, as in Fig. 22. _b_ Case of scalpels from a bas-relief in +the temple of Aesculapius on the Acropolis at Athens. _c_ Trephining +instrument of type still in use. The carpenter’s ‘center bit’ was known +in antiquity, and was probably adapted to the trephine. _a_ and _c_ +represent sixteenth-century instruments of ancient type. No ancient +trephines of Greek origin are known, though a specimen has come down to +us from Mesopotamia, see Fig. 3. + +] + +So much for a normal case which comes to the physician’s hands directly +after the accident. But in less fortunate cases he is not called in so +early, and the wound suppurates before he can bring his Art to bear +upon it. In such a case he is advised: + + ‘Saw the bone immediately to the membrane with a serrated + trephine (Fig. 9, _a_ and _c_), frequently removing the + trephine and testing with the probe all round along the track, + for the bone is sawn through much more quickly if it is already + suppurating and penetrated by the pus. The bone, however, often + happens to be thin in places. Therefore be on your guard not to + apply the trephine at random, but fix it in the bone where it + appears thickest, frequently making an examination and trying + to raise the bone by moving it. And after removing it, continue + such treatment as may appear advantageous to the wound, + according to circumstances.’ + +Among the works of the _Hippocratic Collection_ is a lecture note-book +known by the title _Concerning the things in the Surgery_. It is +written in very abbreviated style and consists of mere headings. +Nevertheless, our attention is arrested by its startling modernness, +when we read such a category as this: + + ‘Operative requisites in the surgery: the patient; the + operator; assistants; instruments; the light, where and how + placed; the patient’s person and apparatus. The operator, + whether seated or standing, should be placed conveniently to + the part being operated upon and to the light. Each of the two + kinds of light, ordinary or artificial, may be used in two + ways, direct or oblique.’ + +Or again, such details as: + + ‘The nails [of the operator] neither to exceed nor come short + of the finger-tips. Practise using the finger-ends. Practise + all operations with each hand and with both together, your + object being to attain ability, speed, painlessness, elegance + and readiness. Let those who look after the patient present the + part for operation as you want it, and hold fast the rest of + the body so as to be all steady, keeping silence and obeying + their superior.’ + +Are we not here reminded of an up-to-date operator and operating +theater? + +In the _Hippocratic Collection_ the physician attends cases of every +type, and does not refuse to do his best for a case because the use +of an instrument is demanded. He is thus no ‘specialist’. But the +mass of his practice lay with cases to which instrumental treatment +was inapplicable. In cases in which surgical intervention was not +justified the Hippocratic physician adopted for the most part what is +called an ‘expectant’ line of treatment. Realizing that, in general, +the tendency of the body is to recover, he contented himself with +‘waiting on Nature’. This does not by any means imply that he was +helpless, for much could be done by nursing, regimen and diet to aid +the patient in that conflict which he alone must fight out. For the +conduct of that great battle wise and useful directions are recorded. +But believing in _the healing power of Nature_--the famous phrase is +used in the Hippocratic writings--the physician was none too eager to +administer drugs. In the state of knowledge of the day this reluctance +was well-judged. Nevertheless the Hippocratic drugs, though neither +numerous nor complex, were some of them very efficient, and their +judicious if reluctant use at the right juncture saved many a life. + +_The Aphorisms_ is the most famous book with which the name of +Hippocrates is associated, and is as likely as any of the Collection +to be by Hippocrates himself. It consists of a series of very brief +generalizations. Many of these have been confirmed by the clinical +experience of later ages. Some have passed into medical commonplaces, +others have become popular proverbs. The style of the work suggests an +aged physician reflecting on the experience of a lifetime. Among modern +medical writings its closest analogue is perhaps the _Commentaries_ of +the great English physician, William Heberden the elder (1710-1801), +which was commenced by him after the age of seventy, occupied the last +twenty years of his life, contained a summary of the whole of his +vast experience, and was published by his son after his death. If the +_Aphorisms_ is similarly a work of the old age of Hippocrates it may be +dated about 380 B.C. A few extracts give a good idea of the nature of +the book. + + ‘Life is short and Art is long; the Crisis is fleeting, + Experiment risky, Decision difficult. Not only must the + physician be ready to do his duty, but the patient, the + attendants, the external circumstances must conduce to the + cure.’ + + ‘Old persons bear fasting most readily, next adults, and young + people yet less; least of all children, and of these least + again those who are particularly lively.’ + + ‘If in any illness sleep does harm, it is a symptom of deadly + import.’ + + ‘When sleep puts an end to delirium, it is a good sign.’ + + ‘Weariness without cause indicates disease.’ + + ‘If there be a painful affection in any part of the body, and + yet no suffering, there is mental disorder.’ + + ‘To eat heartily after a long illness without putting on flesh + is a bad portent.’ + + ‘Food or drink slightly inferior in itself, but more pleasant, + should be preferred to that better itself, but less pleasant.’ + + ‘The old have fewer illnesses than the young, but if any become + chronic with them they generally carry it with them to the + grave.’ + + ‘Those naturally very fat are more liable to sudden death than + the thin.’ + + ‘The dry seasons are more healthy than the rainy, and attended + by less mortality.’ + + ‘Cold sweats in conjunction with an acute fever indicate death, + but with a milder fever only prolonged sickness.’ + + ‘Convulsions supervening on a wound are deadly.’ (Tetanus, cp. + p. 267.) + + ‘Those attacked by tetanus either die within four days, or if + they get through these they recover’ (compare pp. 257 and 267). + + ‘Phthisis comes on mostly from eighteen to thirty-five years of + age.’ + + ‘It is fatal for a woman in pregnancy to be attacked by one of + the acute diseases.’ + + ‘In cases of jaundice, hardening of the liver is a bad sign.’ + + ‘We should observe the appearance of the eyes in sleep. If any + of the white show through the eyelids when closing, this is a + bad sign and very dangerous, unless it be due to diarrhoea or + taking a purgative.’ + + ‘An attack of delirium with laughter is less dangerous than + with despondency.’ + + ‘Apoplexy is commonest between the ages of forty and sixty.’ + + ‘If you give the same nutriment to a patient in a fever and to + a person in health, the patient’s disease is aggravated by what + adds strength to the healthy man.’ + +The chief clinical achievement of the _Hippocratic Collection_ lies +in the descriptions of actual cases. These descriptions are not only +without parallel during nearly 2,000 years, but they are models of +what succinct clinical records should be. They are clear and short, +they give all the leading features and yet they show no attempt to +prejudge the importance of any particular feature. The records of +these cases illustrate the Greek genius for seizing the essential. The +writer does not betray the least wish to exalt his own skill. He seeks +merely to put the data before the reader for his guidance under like +circumstances. It is a reflex of the spirit of honesty in which these +men worked that in the great majority of the cases they record death +ensued. Two of these remarkable descriptions may be given: + + ‘The woman with quinsy, who lodged with Aristion; her + complaint began in the tongue; voice inarticulate; tongue + red and parched. _First day_, shivered, then became heated. + _Third day_, rigor, acute fever; reddish and hard swelling + on both sides of neck and chest; extremities cold and livid; + respiration elevated; drink returned by the nose; she could + not swallow; alvine and urinary discharges suppressed. _Fourth + day_, all symptoms exacerbated. _Fifth day_, died.’ + +This was a case of Diphtheria. The quinsy, the paralysis of the palate +leading to return of the food through the nose, and the difficulty +with speech and swallowing are typical results of this affection which +was here complicated by a spread of the septic processes into the neck +and chest, a not uncommon event in the disease. The rapid onset of the +conditions is rather unusual, but may be explained if we regard the +case as a mild and unnoticed diphtheria, subsequently complicated by +paralysis and by secondary septic infection, for which reason she came +under observation. + + ‘In Thasos, the wife of Delearces, who lodged on the plain, + through sorrow was seized with an acute and shivering fever. + From first to last she always wrapped herself up in her + bedclothes; kept silent, fumbled, picked, bored, and gathered + hairs [from the clothes]; tears and again laughter; no sleep; + bowels irritable but passed nothing; when urged drank a + little; urine thin and scanty; to the touch the fever was + slight; coldness of the extremities. _Ninth day_, talked + much incoherently, and again sank into silence. _Fourteenth + day_, breathing rare, large and spaced, and again hurried. + _Seventeenth day_, after stimulation of the bowels she passed + even drinks, nor could retain anything; totally insensible; + skin parched and tense. _Twentieth day_, much talk, and + again became composed, then voiceless; respiration hurried. + _Twenty-first day_, died. Her respiration throughout was rare + and large; she was totally insensible; always wrapped up in her + bedclothes; throughout either much talk, or complete silence.’ + +We have here a description of low muttering delirium, a common end of +continued fevers, as, for instance, Typhoid. It resembles the condition +known to physicians as the ‘typhoid state’. Incidentally the case +contains a reference to a type of breathing common among the dying. The +respiration becomes deep and slow, as it sinks gradually into quietude +and becomes rarer and rarer until it seems to cease altogether, and +then it slowly becomes more rapid and so on alternately. This type of +breathing is known to physicians as ‘Cheyne-Stokes’ respiration, in +commemoration of two distinguished Irish physicians of the last century +who brought it to the attention of medical men. In our own time it has +been partially explained on a physiological basis. + +We may note that there is another and even better pen-picture of +Cheyne-Stokes respiration in the _Hippocratic Collection_. We read +of one ‘Philescos who lived by the wall and who took to his bed on +the first day of acute fever.’ About the middle of the sixth day he +died, and the physician notes that ‘the respiration throughout was +_like that of a person recollecting himself_ and was large and rare’. +Cheyne-Stokes breathing is admirably described as ‘that of a person +recollecting himself’. + +Immense and, as some may think, overwhelming importance is laid by the +Hippocratic writings upon the art of ‘Prognosis’, that is of predicting +the course which the disease will take. The work to which the title +_Prognostics_ is attached represents a very lofty standard of practice. +We quote from it a description of the signs of death to which the +name of _Hippocratic facies_ has become attached. It is imitated by +Shakespeare in his description of the death of Falstaff in Henry V +(_Act II, Scene 3_). + + ‘You should observe thus in acute diseases; first the + countenance of the patient, if it be like those of persons + in health, and especially if it be like itself, for this is + best of all. But the opposite are the worst, such as these: + a sharp nose, hollow eyes, collapsed temples; the ears cold, + contracted, and their lobes turned out; the skin about the + forehead rough, stretched and parched; the colour of the face + greenish, dusky, livid or leaden. + + ‘If the countenance be such at the beginning of the disease, + and if this cannot be accounted for by the symptoms, inquiry + must be made whether the patient has been sleepless, whether + his bowels have been very loose, or whether he has wanted food. + If any of these be confessed, the danger is to be reckoned so + far the less, and it will become obvious in a day and night + whether or no the appearance come of these. But if no such + cause exist and if the symptoms do not subside in this time, be + it known for certain that the end is at hand.’ + +These glimpses will give some idea of Rational Medicine in the making. +In the fourth century B.C. Medicine emerges as a definite part of the +scientific consciousness. Rational Medicine is now in being. + + +§ 4. _Aristotle._ + +During the fourth century B.C. there lived and worked one whose thought +has stamped itself on the whole subsequent course of the biological and +medical sciences, and indeed of all Science. + +Aristotle (384-322 B.C.) was a provincial Greek and son of a Macedonian +physician. At seventeen he became a pupil of Plato at Athens. After +Plato’s death in 347 Aristotle crossed the Aegean to reside in Asia +Minor. The main part of his biological observations was made during +his stay there. In 342 B.C., at the request of King Philip of Macedon, +Aristotle became tutor to Philip’s son, Alexander the Great. He +remained in Macedon for seven years. About 336, when Alexander departed +for the invasion of Asia, Aristotle returned to Athens, where he taught +for the rest of his life. He died in 322 B.C., a few months after his +pupil Alexander. + +Aristotle was the great codifier of ancient Science. On him all +subsequent biological development, including that of modern times, +is surely based. In his wonderful biological works, which are still +read by naturalists, he discusses many problems current to this very +day. He laid the basis of the doctrine of Organic Evolution in his +teaching concerning the _Scala Naturae_ ‘Ladder of Nature’ (Fig. 10). +He developed coherent theories of Generation and Heredity. He founded +Comparative Anatomy and he dissected many animals. He did not, however, +anatomize the human body. + +[Illustration: FIG. 10. The _Ladder of Nature_ according to Aristotle.] + +Aristotle gave good descriptions of some organs, regarded from the +standpoint of Comparative Anatomy. These descriptions he sometimes +illustrated by drawings, + +the first anatomical figures of which we have a record. In some cases +these drawings can be restored with confidence. Thus, he gave an +account of the uterus, the nomenclature of which has been retained in +more or less modified form to our own time (Fig. 11). Among the best +anatomical descriptions given by Aristotle is that of the ruminant +stomach. Perhaps his most extraordinary anatomical feat is his account +of the development of the dogfish _Mustelus laevis_, which he showed +was attached to its mother’s womb in a way very similar to the embryo +of a mammal (Fig. 12). This raised the admiration of the greatest +modern morphologist, Johannes Müller (1807-58, pp. 211-13), and would +in itself be sufficient to establish the claim of Aristotle to a place +in the front rank of observing naturalists. Aristotle gave fairly +accurate descriptions of the branches of the great veins and of +the superficial vessels of the arm of mammals. He realized that the +arteries are usually accompanied by veins. He described the generative +and digestive organs of cephalopod Molluscs, and many other parts of +many other animals. + +[Illustration: + +FIG. 11. The womb with the names of its parts as given by Aristotle. +These names remain, in various forms, in modern anatomy. + +FIG. 12. Embryo dogfish, _Mustelus laevis_, after Johannes Müller. The +little creature is shown attached to the wall of its mother’s womb, +somewhat after the manner of a mammal. + +] + +Something should be said of the errors of Aristotle. Though an +excellent Naturalist, he was in general much weaker in Physiology. +Thus, he made no proper distinction between arteries and veins. He +failed to trace any adequate relations between the sense organs, the +nerves, and the brain. His refusal to attach great importance to +the brain is remarkable. Primacy he placed with the heart, which he +regarded also as the seat of the intelligence. This was contrary not +only to the medical opinion of his day, but also to the popular view, +voiced, for instance, by Aristophanes in his play _The Clouds_, written +about 400 B.C., where we read of a man who had _concussion of the +brain_. Moreover, Aristotle’s teacher Plato placed the seat of thought +and feeling in the brain. From all we know of Aristotle, it seems +probable that he did not take up this attitude without evidence. It +seems likely that he had experimented on the brain and found it devoid +of sensation. Hence his view, opposed to current belief, that it is +not associated with thought. Aristotle regarded the brain simply as an +agent for cooling the heart, and preventing it from being over-heated. +This cooling process, he considered, was effected by the secretion of +_phlegm_ (_pituita_), an idea still preserved in our anatomical term +the _pituitary body_. + +The views of Aristotle have had a vast influence in determining +the direction of medical thought. For more than two thousand years +Aristotelian philosophy, in more or less corrupted form, constituted +the main intellectual food of mankind. Without some knowledge of the +biological verdicts of Aristotle, it is impossible to understand the +course taken by Rational Medicine. The influence of Aristotle is +specially evident in certain basic biological conceptions. + +The problem of the nature of Generation is one in which Aristotle +never ceased to take an interest. Among the methods by which he sought +to solve it was embryological investigation. His most important +embryological researches were made upon the chick. His choice was most +fortunate, and the chick has remained, to this day, the classical +subject of embryological research. Aristotle asserts that the first +signs of life in the hen’s egg are noticeable on the third day, the +heart being visible as a palpitating blood-spot. As it develops, two +meandering blood-vessels extend to the surrounding tunics. A little +later, he observes, the body becomes distinguishable, at first very +small and white, the head being clearly distinguished and the eyes very +large (Figs. 46-7, p. 117). To follow the main features of the later +stages was a comparatively easy task. + +Aristotle was greatly impressed by these phenomena. He lays stress on +the early appearance of the heart in the embryo. Corresponding to the +general gradational view that he had formed of Nature, he held that the +most primitive and fundamentally important organs make their appearance +before the others. Among the organs all give place to the heart, which +he considered the first to live and the last to die. In the heart, as +we have seen, he placed the seat of the intelligence. + +Thus, not only in his account of the ‘Ladder of Nature’, but also +in his theories of individual development, Aristotle exhibits some +approach to evolutionary doctrine. This is somewhat obscured, however, +by his peculiar view of the nature of procreation. On this topic his +general conclusion is that the material substance of the embryo is +contributed by the female, but that this is mere passive formable +material, almost as though it were the soil in which the embryo grows. +The male, by giving the principle of life, the _soul_ (_psyche_), +contributes the essential generative agency. But this _soul_ is not +material, and it is not, therefore, theoretically necessary for +anything material to pass from male to female. The material which does +in fact pass with the semen of the male is, as the older philosophers +would have said, an _accident_, not an _essential_. The essential +contribution of the male is not matter but _form_ and _principle_. + +The female then only provides the _material_, the male the _soul_, the +form, the principle, that which makes life. Aristotle was thus prepared +to accept instances of fertilization without material contact, i.e., +in effect, _parthenogenesis_ or ‘virgin birth’. In the centuries that +came after him such instances were not infrequently adduced, and this +doctrine was given a special turn by Christian theologians. Belief in +the ‘accidental’ character of the material contribution of the male was +common among men of science till the nineteenth century. The general +attitude as to the nature of fertilization set forth, for instance, by +William Harvey (1578-1657, pp. 111-14) in his book, _On the Generation +of Animals_, published in London in A.D. 1651, is practically identical +with the views of Aristotle published in Athens about 350 B.C., just +2,000 years earlier. It is of great interest to note that very recent +embryological research goes some way to confirm this view of Aristotle. +Without any intervention of the male sexual element, it is possible +so to stimulate the egg mechanically as to produce a perfect animal +which is thus fatherless from the first. The male element is indeed +unnecessary and, in fact, transmits only hereditary characters. + +We must say something concerning Aristotle’s conceptions of the nature +of Life itself. He was before all things a ‘vitalist’. For him the +distinction between living and not-living substance is to be sought not +in material constitution, but in the presence or absence of something +that he calls _psyche_, which we may translate ‘Soul’. His teaching on +this topic had the profoundest influence on subsequent anatomical and +physiological thought. + +Aristotle’s theory as to the relation of this Soul to material things +is a difficult and complicated subject. Its adequate discussion would +take us beyond our theme. He holds, however, that the Soul is related +to the idea of _form_. In living things the soul is that which gives +form. It is the pervasion by the soul that leads to the determinate +development of the body and its parts. This activity of the Soul, under +the Aristotelian term _Entelechy_ (which we may perhaps translate ‘the +indwelling perfectability’ or ‘purposiveness’, see _Preface_), has an +important place in modern biological theory, which has, indeed, swung +definitely in the direction of the Aristotelian position. + +Aristotle defines Life, existing in Matter, as ‘the power of +self-nourishment and of independent growth and decay’. Of the Soul, the +principle of Life, he distinguishes three orders or types, the lowest +_vegetative_, or nutritive and reproductive, next the _animal_ or +sensitive, and highest the _rational_ or intellectual soul. The last, +he at first held, was peculiar to man, but later he modified this view. + +[Illustration: FIG. 13. The four _Elements_ in association with the +four _Humors_ and the four _Qualities_.] + +The history of the reception of Aristotle’s science by later ages is +very strange to modern eyes. Of all Aristotle’s scientific teachings, +men clung most firmly for many centuries not to his finely thought-out +biological conceptions, but to a doctrine of the constitution of +matter of which the modern student hears nothing. Aristotle, following +more ancient writers, held that there were four primary and opposite +fundamental _Qualities_, the _hot_ and the _cold_, the _wet_ and +the _dry_. These met in binary combination to constitute the four +Essences or Existences which entered in varying proportions into the +constitution of all Matter. The four Essences, or, to give them their +usual name, _Elements_, were _earth_, _air_, _fire_, and _water_. Thus, +water was wet and cold, fire hot and dry, and so forth. With this +theory later writers combined the somewhat similar Hippocratic doctrine +which held that the body was composed of the four ‘Humors’ or liquids: +_blood_, _phlegm_, _black bile_ (melancholy), and _yellow bile_ +(choler). Some of the Hippocratic physicians had associated excess of +the Humors with various types of bodily constitution. Their followers +made much of the ‘temperaments’ resulting therefrom, and according +to the prevailing humor they distinguished the sanguine, phlegmatic, +melancholy or choleric temperament (Fig. 34, p. 97). + +These conceptions, now departed altogether from our scientific +discipline, still persist embedded in our language. Poetry still uses +such ideas as the ‘raging of the elements’ and ‘elemental forces’. +We may yet speak of a ‘fiery nature’ or an ‘aerial spirit’. We know +what is meant by a _sanguine_ or a _phlegmatic_ temperament, and a +_melancholy_ or _choleric_ disposition, and such words conjure up +real pictures in our minds (Fig. 34). Until it began to be undermined +by Robert Boyle (1627-91) and others in the seventeenth century, the +doctrine of the four elements persisted in its entirety, while ideas +and terms derived from the old humoral pathology can, in fact, be +traced in the medicine of the twentieth century. + +The biological activity of the school of Aristotle was continued after +his death by his pupil Theophrastus (372-287 B.C.). Especially the +writings on plants of Theophrastus are instinct with a thoroughly +scientific spirit, and are rightly regarded as the basic documents +of the science of Botany. Nevertheless, his works had little effect +or influence on his contemporaries and successors. With Theophrastus +the purely biological school of Aristotle may be said to come to an +end. The biological sciences ceased, for many centuries, to be studied +for their own sake and became mere handmaidens of Medicine. Neither +mistress nor servant was the better for the change. + + + + +II + +THE HEIRS OF GREECE + +(300 B.C. TO A.D. 200.) + + +§ 1. _The Alexandrian School._ + +Soon after Aristotle, about 300 B.C., a great medical school was +founded at Alexandria in Egypt. That country had been conquered by +Alexander the Great, after whom the town was named. On Alexander’s +death, Egypt came under the rule of one of his generals, Ptolemy, +who established a dynasty which became extinct with the famous Queen +Cleopatra, thirty years before the Christian era. Alexandria was a +favorite residence of this Greek dynasty and became more Greek than +Egyptian. Ptolemy and his successors were patrons of learning, and +at the Alexandrian school remarkable anatomical and physiological +researches were made. These were the work of Greek physicians who, in +the tradition of their people, were only too wont to associate their +discoveries with sweeping theoretical generalizations, often on very +inadequate bases. + +The two earliest medical teachers at Alexandria were also the greatest, +Herophilus of Chalcedon, who flourished about 300 B.C., and his +slightly younger contemporary Erasistratus of Chios. Herophilus may +be regarded as the father of Anatomy, Erasistratus as the father of +Physiology. + +Herophilus was probably the first to dissect the human body in public. +He recognized the brain as the central organ of the nervous system and +regarded it as the seat of the intelligence, thus reversing the verdict +of Aristotle on the primacy of the heart. He was the first to grasp the +nature of the nerves, which he distinguished as connected with motion +and sensation (Fig. 98), though he did not separate them clearly from +tendons and sinews. He greatly extended the knowledge of the parts +of the brain. Certain parts of the brain still bear titles which are +translations of those which he gave them. He also made the first clear +distinction between arteries and veins. + +At the time of the institution of the Alexandrian medical school, and +for long after, there flourished that view of the structure of the +world known as _atomic_, propounded by the philosopher Democritus +(_c._ 400 B.C.). The chief exponent of the theory was Epicurus +(342-270), whose philosophy was of the order which we should now call +‘materialistic’. For it the only ultimate realities were atoms and +‘the void’, and everything was ultimately expressible in these terms. +Epicurean philosophy was not without its reactions on Medicine at +Alexandria, where its leading exponent was Erasistratus of Chios. + +Erasistratus was essentially a rationalist and professed himself a +foe to all mysticism. In the last resort, however, he had to invoke +the idea of Nature as a great artist acting as an external power, +shaping the body according to the ends to which it must act. This is +in contrast with Aristotle’s view of the ‘soul’ as an _Entelechy_ (p. +33), an innate and inherent factor. Erasistratus sought to express +his views in atomic terms, but, to make physiology intelligible, he +added a conception, _Pneumatism_, found also among older thinkers. +Pneumatism is the belief that the phenomena of life are associated with +the existence of a subtle vapor, ‘pneuma’ or spirit, which permeates +the organism, and causes its movements. This subtle vapor is held to +have some affinities with the air we breathe. Pneumatism is, in fact, a +primitive attempt to explain the phenomena of respiration. + +Erasistratus observed that every organ is equipped with a threefold +system of ‘vessels’, vein, artery, and nerve, which divide to the +very limits of vision, and he considered that the process of division +continues beyond those limits. The minute divisions of these vessels, +plaited together, he believed to make up the tissues. Veins, arteries, +and nerves are, for him, made of minute tubes of the same nature as +themselves, through which they are nourished. Blood and two kinds of +pneuma are the essential sources of nourishment and movement. The blood +is carried by veins. Air, on the other hand, is taken in by the lungs +and passes to the heart, where it becomes changed into a peculiar +pneuma, the _Vital Spirit_, which is sent to the various parts of the +body by the arteries. This spirit is carried to the brain, in the +cavities or ‘ventricles’ of which it is further changed to a second +kind of pneuma, the _Animal Spirit_. The animal spirit is conveyed to +different parts of the body by the nerves, which are hollow. + +In the brain Erasistratus observed the convolutions, noted that they +were more elaborate in man than in animals, and associated this +complexity with the higher intelligence of man. He distinguished +between the main parts of the brain, the ‘cerebrum’ and ‘cerebellum’ +(Fig. 100, p. 210), and gave a detailed description of the ‘cerebral +ventricles’ or cavities within the brain and of the ‘meninges’ or +membranes that cover the brain. He considered that the cerebral +ventricles were filled with _Animal Spirit_. (Compare Galen’s scheme, +p. 58.) + +Erasistratus attained to a clear view of the action of muscles in +producing movement. He regarded the shortening of muscles as due to +distension by _Animal Spirit_ conveyed to the muscles by the nerves. We +may note that similar theories as to the nature of muscular action were +again set forth, on theoretical grounds, in the seventeenth century by +Descartes (1596-1650, pp. 127-8) and by Borelli (1608-79, pp. 129-30), +but were rebutted by the experiments of Swammerdam (1637-80, p. 123). +We may recall that we are still in the dark as to the mechanism of +contraction of muscle fiber, the structure of which was first revealed +by Leeuwenhoek (1632-1723, Figs. 55-56A, p. 121). + +Erasistratus considered the chief cause of disease to be excess +of blood or _Plethora_. Diseases thus caused differ according to +their site. Among them are coughing of blood, epilepsy, pneumonia, +tonsillitis, &c. Most of these diseases could be treated by diminishing +the local supply of blood by starvation. Among his contemporaries and +successors blood-letting was an habitual practice applied to almost +every condition. Erasistratus employed it but rarely, and his followers +banned it altogether. He was consistently opposed to violent remedies. +Among the therapeutic measures which he favored were regulated +exercise, diet, and the vapor bath. + +Erasistratus complained that many physicians of his time were not +interested in Hygiene. He therefore wrote a treatise on the subject. +Though he regarded Hygiene as a means of substituting prevention for +cure, this did not prevent him from being extremely careful and precise +in his treatment of cases. + +After the first generation or two, the activity of the Alexandrian +medical school flagged, though the city long remained a great teaching +center, and minor medical advances were made. Surgery (cf. Fig. 14) +seems to have languished less than Medicine. The stagnation in medical +matters at Alexandria is in contrast to the continued activity there in +Mathematics, Astronomy, Mechanics and Geography. + +With the absorption of Egypt into the Roman Empire in 50 B.C. and +the extinction of the Ptolemaic dynasty by the death of Cleopatra in +30 B.C., Alexandria ceased to have great scientific importance. The +school continued for centuries with restricted activity and devoid +of all originality. Intellectually, it had become subordinate to the +Metropolis. Rome was now mistress of the world and the future of +Medicine must be considered from the point of view of the Roman Empire. + +[Illustration: + +FIG. 14. INSCRIBED TABLET OF ABOUT 100 B.C. from the wall of the temple +of Kom-Ombos in Upper Egypt. The temple itself was built by Ptolemy +VII (181-146 B.C.), but the carving is later. It is divided into four +partitions. These illustrate the surgical instruments in use in Egypt +during Alexandrian times. + +In the partition to the extreme left can be seen two cupping-glasses +(cf. Fig. 8), a case of instruments (cf. Fig. 15), a pair of shears, a +sponge, a probe, a pair of fine forceps, and two knives (cf. Fig. 9). + +In the next partition to the right can be seen two large forceps, two +bags or flasks, a strigil, two magic eyes, a pair of scales, and two +growing plants. + +In the next partition to the right can be seen several hooks of +different forms, several knives, and two or three pairs of forceps. + +In the partition to the extreme right can be seen a bifid probe, a pair +of tongs, a long-bladed knife, probes, a double hook, a saw, a cautery, +and several objects probably intended to represent bandages. ] + + +§ 2. _Medical Teaching in the Roman Empire._ + +The original native Roman medical system was quite devoid of scientific +elements and was that of a people of the lower culture. Interwoven, +as is all primitive Medicine, with ideas that trespass on the domains +of religion and magic, it possessed that multitude of ‘specialist +deities’ which was so characteristic of the Roman cults. The entire +external aspect of Roman medicine was changed by the advent of Greek +science. Yet, notwithstanding the large medical field that the Western +Empire provided, and the wide acceptance of Greek medicine by the upper +classes, it is remarkable that the Latin-speaking peoples produced no +eminent physician. + +At first scientific medical education at Rome was entirely a matter of +private teaching. The earliest important scientific teacher there was +the Greek Asclepiades of Bithynia (died _c._ 40 B.C.), a contemporary +of the poet Lucretius and, like him, an Epicurean. Asclepiades, like +Erasistratus, imported the atomic view of Democritus into Medicine. He +deeply influenced the course of later medical thought, ridiculed the +Hippocratic attitude of relying on the ‘healing power of nature’ which +he regarded as a mere ‘meditation on death’, and urged that active +measures were needed for the process of cure to be ‘seemly, swift and +sure’. He founded a regular school at Rome which continued after him. + +At first the school was the mere personal following of the physician, +who took his pupils and apprentices round with him on his visits. At +a later stage such groups combined to form societies or colleges, +where problems of the art were debated. Towards the end of the reign +of Augustus (27 B.C.-14 A.D.) or the beginning of that of Tiberius +(14 A.D.-37 A.D.), these societies constructed for themselves a +meeting-place on the Esquiline Hill. Finally the emperors built +halls or _auditoria_ for the teaching of Medicine. The professors at +first received only the pupils’ fees. It was not until the time of +the Emperor Vespasian (reigned A.D. 70-9) that medical teachers were +given a salary at the public expense. The system was extended by later +emperors. + +Thus Rome became a center of medical instruction. After a time +subsidiary centers were established in other Italian towns. From Italy +the custom spread and we meet traces of such schools at the half-Greek +Marseilles as well as at Bordeaux, Arles, Nîmes, Lyons, and Saragossa. +For the most part these provincial schools produced workaday medical +men, few of whose writings have come down to us. They were perhaps +largely training-places for the army surgeons. That class seldom had +scientific interests, though Dioscorides, one of the most prominent +physicians of antiquity, one who earned the respect of Galen and has +deeply influenced the modern pharmacopoeia, served in the army under +Nero. His book is, in fact, an extremely useful though ill-arranged +compendium of drugs. Dioscorides wrote in Greek, and his work was not +translated into Latin until the sixth century of our era. + +The earliest scientific medical work in Latin is the _De re medica_ of +Celsus, which was prepared about A.D. 30. It is in many ways the most +readable and well-arranged ancient medical work that we have. It is, +however, not an original work but a compilation from the Greek, and the +sole surviving part of a complete encyclopaedia of knowledge. Many of +its phrases are closely reminiscent of the _Hippocratic Collection_. +The ethical tone is high and the general line of treatment sensible and +humane. Celsus, though almost forgotten in the Middle Ages, was the +first classical medical writer to be printed (A.D. 1476). + +The treatise of Celsus opens with an interesting account of the History +of Medicine. It then passes on to deal with diet and the general +principles of therapeutics and pathology, next it discusses internal +disease, and then turns to external diseases. The last part of the work +is devoted to surgery, and is perhaps the most valuable of the whole. + +Celsus professes himself a follower of Asclepiades of Bithynia (p. +41), but, unlike his master, he by no means despises the Hippocratic +_expectant_ method of ‘waiting on the disease’. In many matters we are +struck with + +his boldness as a surgeon. Thus he describes plastic operations on the +face and mouth, and the removal of polypus from the nose. He tells too +of the very dangerous operation for extirpating a goiter (p. 303), and +of cutting for stone. He gives an excellent account of what might be +thought the modern operation for removal of tonsils. Noteworthy also +is his description of dental practice which includes the wiring of +loose teeth and an account of a dental mirror. An idea of the surgical +instruments in use in his time can be obtained from those recovered +from Pompeii (Fig. 15). + +[Illustration: FIG. 15. ROMAN SURGICAL INSTRUMENTS of the first century +A.D. found at Pompeii. + + _a._ Forceps, probably for extracting teeth. + + _b._ Small pocket-case of instruments containing sharp spoon, + probe, &c. + + _c._ Fine-toothed forceps. + + _d._ Trocar and cannula for tapping fluids confined in cavities. + + _e._ Speculum for examining orifices and cavities. + + _f._ Instrument for dilating wounds that they may be more fully + examined. +] + + +§ 3. _Medical Services of the Roman Empire._ + +If, in Medicine itself, the Roman achieved but few advances, in the +organization of medical service, and especially in the department which +deals with public health, his position is far more noteworthy. All +Latin writers on architecture give much attention to the orientation, +position and drainage of buildings. From an early date sanitation and +public health drew the attention of statesmen. Considering the dread of +the neighborhood of marshes on the part of these practical sanitarians +of Ancient Rome, and in view of modern knowledge of the mosquito-borne +character of Malaria (pp. 284-5), it entertaining to find the mosquito +net ridiculed by the poets Horace, Juvenal and Propertius! + +Sanitation was a feature of Roman life. Rome was already provided with +_cloacae_ or subterranean sewers in the age of the Tarquins (6th cent. +B.C.). The _Cloaca Maxima_ itself, the main drain of Rome, which is +still in use, dates back to that period. + +The antiquity of hygienic ideas is seen in an interdict, by a law +of about 450 B.C., against burials within the city walls and in the +instructions issued to the town officials to attend to the cleanliness +of the streets and to the distribution of water. Among these ancient +laws we may note one attributed to the first king of Rome, which +directed the opening of the body in the hope of extracting a living +child in the case of a woman dying in pregnancy. It is the origin of +the so-called ‘Caesarean section’ on the living mother, the method by +which Caesar himself is said to have been brought into the world. At +the date of these decrees physicians in Rome were either slaves or in +an entirely subordinate position. Their status was improved by Julius +Caesar (102-44 B.C.), who conferred citizenship on all who practised +Medicine at Rome, in order to induce physicians to settle there. + +[Illustration: FIG. 16. AQUEDUCT OF NERO. This structure, when +complete, conveyed part of the water-supply of Rome. + +(_From an engraving by Piranesi._)] + +The finest monument to the Roman care for the public health stands yet +for all to see in the remains of the fourteen great aqueducts which +supplied the city with 300,000,000 gallons of potable water daily. No +modern city is better equipped (Fig. 16). + +Under the early Empire a definite public medical service was +constituted. Public physicians were appointed to the various towns and +institutions. A statute of the Emperor Antoninus of about the year A.D. +160 regulates the appointment of these physicians, whose main duty was +to attend to the poor. In the code of the Emperor Justinian (A.D. 533) +is an article urging them to give this service cheerfully rather than +the more subservient attendance on the wealthy. Their salaries were +fixed by the municipal councillors. They were encouraged to undertake +the training of pupils. Inscriptions attest the respect in which these +state physicians were held in many towns. + +It is in connection with the army that we see the Roman medical +system at its best. There was an adequate supply of military medical +attendants who were well organized (Fig. 17). The defects of the Roman +army medical system were, however, absence of any elastic scheme for +the ranking of medical officers, and complete subordination of the +medical to the combatant officer. These facts are of a piece with the +general Roman indifference to theoretical science, and explain + +why the Roman army surgeons made no additions to knowledge. The social +status of the medical staff in the Roman military hierarchy was that of +the non-commissioned personnel, which included accountants, registrars +and secretaries. + +[Illustration: FIG. 17. ROMAN ADVANCED DRESSING-STATION. + +(_From Trajan’s column._) + +To the left two Roman soldiers assist a wounded comrade. To the right +a Roman military surgeon bandages the wounded thigh of a friendly +ally. The costume of the surgeon is almost identical with that of the +soldiers, though he carries a case for ‘first aid’ slung over his +shoulder. + +] + + +§ 4. _Roman Hospitals._ + +The great contribution of Rome to Medicine--and it is a very great +one--is the hospital system. It is a scheme that naturally arose out +of the Roman genius for organization and is connected with the Roman +military system. Among the Greeks, _iatreia_, ‘surgeries’, were well +known; they were, however, the private property of the medical man. +Larger institutions were connected with Aesculapian temples and there +is evidence of some degree of scientific medical treatment in these +places. In the Republican period the Romans were no better off and, +despite the vast numbers of slaves, there was no provision for them +when sick. A temple to Aesculapius had been established on an island of +the Tiber in Republican times. It became the custom to expose the sick +and worn-out slaves on this island of Aesculapius, to avoid the trouble +of treating them. The Emperor Claudius (A.D. 41-54) decreed that such +slaves were free, and that, if they recovered, they need not return to +the control of their masters. Thus, the island became a place of refuge +for the sick poor. We may regard it as an early form of public hospital +(Fig. 18). + +Later writers speak of _valetudinaria_, ‘infirmaries’, for such +persons, and give humane directions for their management. Such +valetudinaria were in use even by free Romans. The excavations at +Pompeii show that a physician’s house might even be built somewhat on +the lines of a modern ‘nursing home’. It was probably in the provinces +that private institutions first developed into subventioned public +hospitals. + +This development of public hospitals naturally early affected military +life. At first, sick soldiers had been sent home for treatment. As the +Roman frontiers spread ever wider this became impossible and military +hospitals were founded at important strategic points. The sites of +several such military hospitals have been excavated. The best explored +is near Düsseldorf and was founded about A.D. 100. + +From the military valetudinarium it was no great step to the +construction of similar institutions for the numerous Imperial +officials and their families in the provincial towns. Motives of +benevolence, too, gradually came in, and public hospitals were +founded in many localities. The idea passed on to Christian times, +and the pious foundation of hospitals for the sick and outcast in the +Middle Ages is to be traced back to these Roman valetudinaria. The +first charitable institution of this kind, concerning which we have +clear information, was established at Rome in the fourth century by +a Christian lady of whom we learn from St. Jerome. The plan of such +a hospital projected at St. Gall in the early years of the ninth +century has survived. It reminds us, in many respects, of the early +Roman military hospitals. These medieval hospitals for the sick must +naturally be distinguished from the even more numerous ‘spitals’ for +travellers and pilgrims, the idea of which may perhaps be traced back +to the rest-houses along the strategic roads of the Empire. + +[Illustration: FIG. 18. ISLAND OF ST. BARTHOLOMEW IN THE TIBER AT ROME. +(_From an engraving by Piranesi._) + +The island was the site of a temple to Aesculapius used as a refuge +for worn-out slaves. It is the first known public hospital. The entire +island is carved in the form of a ship. On its prow can be discerned +the head of Aesculapius and his staff and serpent. ] + + +§ 5. _Galen._ + +The Latin culture, as we have seen, did not adapt itself easily to the +prosecution of scientific Medicine. Long after Greece had ceased to +exist as an independent state such medical writings as appeared were +usually in the Greek rather than in the Latin language. This is true +to the end, and the end came, so far as creative science is concerned, +with the second half of the second century. The scene is then, and for +centuries to come, mainly occupied by the huge overshadowing figure of +Galen. + +Galen of Pergamum (A.D. 130-200) devoted himself to medicine from an +early age, and in his twenty-first year we hear of him studying anatomy +at Smyrna. To extend his knowledge of drugs he made long journeys +to Asia Minor. Later he proceeded to Alexandria, where he improved +his anatomical equipment, and here, he tells us, he examined a human +skeleton. His direct practical acquaintance with human anatomy was +limited to that skeleton, for dissection of the human body was no +longer carried on in his time. Thus, his physiology and anatomy were +derived mainly from animal sources. + +The general medical standpoint of the Galenic is not unlike that of +the Hippocratic writings, but the noble vision of the lofty-minded, +pure-souled physician has utterly passed away. In its place we have an +acute, contentious fellow of prodigious industry, who is frequently +satisfied with a purely verbal explanation. Yet he is an ingenious +physiologist, acquainted with the internal parts, so far as this is +possible from a devotion to dissection of animals, equipped with +all the learning of the schools of Pergamum, Smyrna and Alexandria, +and rich with the experience of a vast practice at Rome. Galen is +essentially an ‘efficient’ man. He has the grace to acknowledge +constantly his indebtedness to the Hippocratic writings. + +Some of Galen’s works are, however, mere drug-lists, little superior to +those of Dioscorides (p. 43). With the depression of the intelligence +that corresponded with the break-up of the Roman Empire, it was these +that were chiefly studied and distributed in the West. The Greek +medical writers after Galen were but his imitators and abstractors, and +they usually imitated and abstracted Galen at his worst. Through some +of them Galen’s works reached the West at a very early period in the +Middle Ages. + + +§ 6. _The Final Medical Synthesis of Antiquity._ + +We now turn to the theoretical content of the vast mass of Galenic +writings. These set forth a medical system of which the substance +is based on the _Hippocratic Collection_ and the form derived from +Aristotle. This synthesis, in more or less corrupted form, provided +the theoretical basis of medical practice for the next fifteen hundred +years. Galen’s view of the human body may be examined under two +aspects, which we describe as (_a_) philosophical and (_b_) descriptive. + +First as to the philosophical aspect. Galen’s voluminous works are +saturated with the theory that all structures in the body have been +formed by the Creator for a known and intelligible end. In the +anatomical works, masses of explanation, based on this view, dilute +the often imperfect accounts of structures. Thus, following the +Aristotelian principle that Nature makes nought in vain, Galen seeks to +justify, the form and structure of every organ--nay, of every part of +every organ--with reference to the functions for which he believes it +is destined. To do this is to claim that in every work of Creation--of +which Man’s body is a type--and in every detail of such work, we can +demonstrate God’s design along known principles. It is to claim, in +fact, a complete knowledge of the Laws of Nature. No modern man of +science, however intoxicated with his own achievements, has as yet +arrogated such powers to himself. To conceive that such claims should +be made by a pious, theistically minded author, the reader must think +himself back into a very different philosophical environment from that +to which we are nowadays accustomed. + +The prevailing philosophy of Galen’s world was the Stoic. Now in the +world of the Stoic philosopher all things were determinate, and they +were determined by forces acting wholly outside Man. The type and +origin of that determination the Stoic sought in the heavens, and found +in the majestic and overwhelming procession of the stars. The recurring +phenomena of the spheres typified, foreshadowed, nay, exhibited and +controlled, the cycle of man’s life. Man dwelt in a finite world, +bounded by a definite frontier--the sphere of the fixed stars. Within +that spherical frontier all things worked by rule--and that rule was +the rule of the heavenly bodies. Astrology had become one of the dogmas +of the Stoic creed. + +To such a world Galen’s determination was in itself no strange thought. +Yet Galen’s view was far from being wholly in accord with Stoicism. +Though a determinism, it was a determinism of perfection in which all +was fixed by a wise and far-seeing God, and was a reflection of His +perfection. Now such a scheme did not ill fit the new creed which was +just beginning to raise its head and was destined to replace Stoicism +and all the other pagan schemes. Galen’s thought, in fact, made a +special appeal to the Christian point of view, and this is, doubtless, +the reason that his works have been preserved in larger bulk than +those of any other pagan writer. The Galenic standpoint appealed +equally to the theological bias of Islam, whose medical knowledge was +based almost entirely on Galen. + +We may now turn from the philosophical to the descriptive bases of +Galen’s medical system, namely to his Anatomy and Physiology. + +We may begin with the bones. These Galen had studied on an actual human +skeleton at Alexandria. He divided them into long bones with a central +canal and flat bones without such a canal. He had a fairly good idea +of the bones of the skull. He regarded the teeth as bones, and he +gives a good description of their origin. He recognized twenty-four +vertebrae terminated by the _sacrum_. Galen gives accurate elementary +descriptions of the vertebrae, of the ribs, of the breastbone, of +the collar-bone, and of the bones of the limbs. He divides joints or +junctions of bones into two main orders, those with movement and those +without movement, and the titles that he gives to his main divisions +have survived in our modern nomenclature. + +As regards the muscular system there can be little doubt that Galen’s +work was in large part of a really pioneer character. Throughout +his works the muscles are perhaps the structures that he describes +most accurately. His writings contain frequent references to form +and function of muscles of various animals. Thus, the dissection of +the muscles of the orbit and larynx was performed on the ox, and the +muscles of the tongue are described from the ape. Occasionally he +indicates that he is aware of the differences between certain of the +muscles he is describing from those of man. For his investigation of +muscles Galen used particularly the Barbary ape (_Macacus inuus_), +a creature anatomically near enough to man for a knowledge of its +detailed structure to be applicable to human Surgery. (Figs. 19 and 20.) + +[Illustration: + +FIG. 19. DISSECTION OF HAND OF MAN. + +FIG. 20. DISSECTION OF HAND OF BARBARY APE. + +The ape’s hand shows all the main muscular and tendinous structures +present in the human hand, though the proportional development differs +somewhat. The same is true of other parts of the body. Galen’s +anatomy, drawn from the Barbary ape, was thus quite serviceable for +many surgical procedures. Apart from proportion, the most obvious +anatomical difference in the hands of the two species is the position +of attachment of the small severed muscle indicated by the asterisk in +both cases. + +] + +Galen’s description of the brain and of the vascular system is inferior +to his account of the bones and muscles. His account of the nervous +system, other than the brain, occupies an intermediate position. His +account of the origin of nerves from the brain has left its traces even +in modern descriptive anatomy. + +Finally we may turn to Galen’s theory of the working of the human body, +that is to his Physiology. + +The basic principle of life in the Galenic physiology was a _spirit_ or +_pneuma_ drawn from the general World-spirit in the act of breathing. +It entered the body through the windpipe or _trachea_ and so passed to +the lung and thence, through the _arteria venalis_--which we now call +the ‘pulmonary vein’--to the left ventricle of the heart, where it +encountered the blood (Fig. 21). But what was the origin of the blood? +To this question his answer was ingenious, and the errors that it +involved remained till the time of Harvey (Fig. 43, p. 113). + +Galen believed that food-substance from the intestines was carried as +‘Chyle’ by the portal vein to the liver. There it was converted into +blood and endowed with a particular pneuma, the _Natural Spirit_, which +bestowed the power of growth and nutrition. Part of this lower-grade +blood was carried from the liver to the right ventricle, where it gave +off impurities by way of the _vena arterialis_, our ‘pulmonary artery,’ +to the lungs, whence they were exhaled in the breath. The venous +blood, thus continuously purified, ebbed to and fro in the veins +for purposes of ordinary nutrition. A very small part of this venous +blood passed through invisible pores in the muscular septum to the left +ventricle. There it mixed with air drawn in from the lung by way of the +_arteria venalis_, our ‘pulmonary vein’. From this mixture was produced +a higher-grade blood, the arterial blood, instinct with the principle +of life and charged with a second kind of pneuma, the _Vital Spirit_. +Blood containing this second kind of pneuma ebbed to and fro in the +arteries endowing the various organs with function. Such as reached the +brain became there charged with the noblest essence of all, the third +pneuma, the _Animal Spirit_ or breath of the soul. The _Animal Spirit_ +was carried from the brain by the nerves--believed to be hollow--and +through them initiated the higher functions of the organism, including +motion and sensation (Fig. 21). + +Among Galen’s most remarkable efforts are the investigations he made +of the physiology of the nervous system. He tells of his experiments +on the spinal cord. Injury to the cord between the first and second +vertebrae caused, he observed, instantaneous death. Section between +the third and fourth produced arrest of breathing. Below the sixth +vertebra it gave rise to paralysis of the chest muscles, breathing +being then carried on only by the diaphragm. If the lesion was lower +the paralysis was confined to the lower limbs, bladder, and intestines. +The physiology of the spinal cord is worked out most ably and in very +considerable detail. + +Galen established no school, nor had he any definite followers. His +self-satisfaction and love of controversy were not of the kind that +would endear him to disciples. On his death in A.D. 200 the active +prosecution of anatomical and physiological inquiry ceased absolutely. +The curtain descends at once, and, for the subject we are discussing, +the Dark Ages have begun. + +Rational medicine in the pagan world descends into darkness as surely +and even more abruptly than Philosophy. The whole system is soon to be +overwhelmed. Alexandria has long been in decline. A mob, fanatically +Christian, has destroyed her school and library, with all the hoarded +wisdom of the pagan past. Men of the new faith fix their eyes on the +wrath to come and the glory after it. In the race for salvation, who +will pause to consider this miserable tenement of clay? Antiquity is no +more. A new age has begun. + +[Illustration: FIG. 21. GALEN’S PHYSIOLOGICAL SYSTEM.] + + + + +III + +THE MIDDLE AGES + +(FROM ABOUT A.D. 200 TO ABOUT A.D. 1500.) + + +§ 1. _The Period of Depression in Europe._ + +The observational period of Antiquity closed with Galen. The centuries +that follow exhibit progressive deterioration of the intellect. For +that deterioration many causes have been assigned. An important factor +was certainly the philosophical outlook of later paganism. Men lacked a +motive for living. Their view of the World was dreary and without hope. +It is sometimes alleged that the advent of Christianity was a factor +in the decay of Science, but Science was, in fact, in headlong decay +before Christianity was in a position to have any real effect on pagan +thought. + +Christianity came to the ancient world as a protest and a revulsion +against the prevailing and extremely pessimistic pagan outlook. +Christianity brought men something for which to live. It was natural +that it should oppose the philosophical basis of pagan thought. In +this sense Christianity was certainly anti-scientific. Early Christian +thought exhibits an aversion to the view which places the whole of +man’s fate under the dominion, the inescapable tyranny, of Natural +Law. It is, however, essential to remember that the early Church, in +developing this opposition, was not dealing with living observational +Science. The conflict was simply with a philosophical tradition which +contained dead, non-progressive and misunderstood scientific elements. + +For some eight centuries from the time that Christianity finally +replaced Paganism in the Roman Empire--from about A.D. 400 to about +A.D. 1200--such remains of classical learning and classical science as +survived were in monastic keeping. It was only in the monasteries that +there were any who cared at all for these things, and it was only in +the monasteries that manuscripts could be either written or preserved. +We cannot be sufficiently grateful to the monks for having succeeded in +preserving even as much as they did. Nevertheless, whether we consider +what they saved or what they lost of medical literature, we can express +no high opinion of either monastic taste or monastic judgment. + +The curse of the Science of Medicine, as of all sciences, has always +been the so-called ‘practical man’, who will consider only the +immediate end of his art, without regard to the knowledge on which it +is based. Monkish medicine had no thought save for the immediate relief +of the patient. All theoretical knowledge was permitted to lapse. +Anatomy and Physiology perished. Prognosis was reduced to an absurd +rule of thumb. Botany became a drug-list. Superstitious practices crept +in, and Medicine deteriorated into a collection of formulae, punctuated +by incantations, which became less understood and further removed +from their originals at each copying. Medicine remained surrounded by +sacred associations (Fig. 22), but the scientific stream, which is its +life-blood, was dried up at its source. + +[Illustration: + +FIG. 22. EARLIEST KNOWN REPRESENTATION OF ST. LUKE AS A PHYSICIAN. +From a seventh-century painting in the underground basilica of Saints +Felix and ‘Adauctus’ at Rome. St. Luke, as an Evangelist, holds a +scroll between his hands; as a Physician he carries suspended from his +left arm a bag containing four instruments, one of which is a lancet. +The head is tonsured like a monk’s. By courtesy of Rev. Father J. R. +Fletcher. + +FIG. 23. PICTURE OF TREPHINING from a thirteenth-century manuscript. +The surgeon is using a well-known and primitive form of drill, the mode +of action of which will be understood by the accompanying diagram, +shown as Fig. 24. + +] + +There was just one area in the Latin West where a slightly higher +standard prevailed. In the South of Italy the Greek tongue still +continued for centuries to be spoken and written. Though civilization +had sadly deteriorated with the disorders of the times, yet there +remained here and there in that region a slightly higher intellectual +standard than prevailed elsewhere in Europe. Moreover, about the same +time as the Norman Conquest in England, there was a Norman Conquest +of South Italy also. The strong arm of the Norman administrator might +wield the weapon of a tyrant, but at least it brought order where +there had been anarchy. Learning under the Normans could lift a timid +head. Notably at the town of Salerno, not far from Naples, there arose +something resembling a medical school. At Salerno in the eleventh +century there was a certain amount of translation of medical works from +Greek into Latin. The choice of works for translation was very poor, +but it was something that enough mental energy existed for the effort. + +[Illustration: + +FIG. 24. Figure to illustrate the mode of action of the instrument used +by the surgeon in Fig. 23. The twist of the thong causes rapid rotation +of the axis. The rotating point is pressed on the skull and gradually +penetrates it. From a drawing of the sixteenth century. + +] + +Salerno differed too from other centers of learning of the time in that +instruction was not entirely under monastic auspices (Fig. 25). Some, +at least, of the Salernitan physicians were laymen. At the time of the +Norman conquest of Salerno, the school was stimulated by the advent of +a wanderer from the East, Constantine by name (died 1087). This man +brought with him medical works in Arabic which he was able to translate +into rude Latin. The Latin versions prepared by Constantine, corrupt, +confused, barbarous, often almost incomprehensible, were yet a better +intellectual fare than that on which the torpid mind of Europe had +long fed. The Salernitan medical writings of the eleventh and twelfth +centuries exhibit some faint-hearted attempts to return to Nature. +Constantine was but the harbinger of the great ‘Arabian revival’ the +further origins of which we must now seek to trace. + +[Illustration: + +FIG. 25. SCENE AT A SIEGE OF SALERNO from a manuscript prepared in +South Italy early in the thirteenth century. An archer transfixes two +of the defenders through the cheeks. A _medicus_ is aiding one of +them. Two nurses, bearing drugs and dressings, attend the medicus. It +illustrates the existence of lay physicians at Salerno at this date. +The medicus is not tonsured. + +] + + +§ 2. _Arabic Medicine._ + +Barbarian incursions sapped and finally destroyed the Western Roman +Empire. The influence of those incursions on the Eastern Empire was +less dramatic. It is true that the intellectual outlook of the East +Roman or Byzantine Empire was no less modified, in the course of time, +than was that of the West. In the absence, however, of any collapse +of the system of government, the ancient Greek learning or rather the +documentary casing in which it was enshrined, was better preserved +than were the Latin traditions. Men in the Eastern Empire could still +read the ancient Greek medical works in the language in which they had +been written, and, if their reading was unintelligent, it was at least +persistent. Moreover, heretical Christian sects on the confines of the +East Roman Empire prepared for themselves translations of many of the +ancient Greek authors. One of these heretical sects, the Nestorians, +exhibited great missionary activity. It was perhaps on this account +that the Nestorians prepared translations of many Greek medical works +into their own language, Syriac. + +In the seventh century, Islam arose and soon swept over vast areas +that had erstwhile belonged to the Emperor of the East. The territory +occupied by the Nestorians in the Near East came early under Moslem +rule. The Moslems, at first indifferent to infidel learning, came +gradually to appreciate it. In the ninth century a great and united +Moslem Empire was established with its center at Bagdad. The need for +translation of Greek scientific works into Arabic, the common language +of Islam, now asserted itself. One after another the medical writings +that had been turned into Syriac were translated into Arabic, and Greek +Science in general and Greek Medicine in particular were thus spread +far and wide in the Moslem world. + +Greek science in the Arabic version came in time to be better +understood by Arabic-speaking students than it had been by any since +Galen. Nor were the Arabic-speaking peoples content to rest on the +texts that had thus descended to them from antiquity. A considerable +number of Arabic writers produced works of their own, some not wholly +devoid of originality. Unfortunately these men were without effective +anatomical or physiological basis for their medical knowledge, though +many of them were acute clinical observers, and, even from the modern +point of view, some of their works are not wholly contemptible. Thus +Rhazes (860-932), a native of Basra on the Persian Gulf, wrote a work +containing the first known description of Measles, which he carefully +distinguishes from Small-pox. The Persian Avicenna (980-1036) composed +a vast encyclopaedia of medical knowledge, the so-called _Canon_, which +served as the main text-book of Medicine both among the Arabic-speaking +peoples and in the Latin West until the seventeenth century. The Jew, +Isaac of Kairouan (852-952), composed a treatise on fevers which was +the best account of the subject available in Europe during the entire +Middle Ages. The Moor, Albucasis (11th cent.), left a text-book of +surgery which was an important element in the revival of the subject in +Italy and France. + +These are only prominent members of a vast school of writers who +flourished in Arabic-speaking countries between the ninth and +thirteenth centuries. The bulk and number of their writings is +portentous. Many of their works were translated into Latin, often +by Jewish translators (Fig. 26). These Latin translations caused a +reawakening of the intellect of Europe, and provided the staple reading +in the medieval universities throughout the Middle Ages. + +[Illustration: + +FIG. 26. A JEWISH TRANSLATOR receiving an Arabic medica volume from an +Eastern potentate (right) and handing it, translated into Latin, to a +Western monarch (left). From a thirteenth-century manuscript. + +] + + +§ 3. _The Medieval Awakening._ + +The Spanish peninsula had been inundated by the Islamic tide as early +as the eighth century. After a while the waters began to recede. The +speech and culture of Islam had become stamped upon the natives of the +peninsula, and were only gradually replaced by the Latin civilization +and dialect which we now call Spanish. During the centuries of Islamic +retreat, there was thus a bilingual population in the peninsula, so +that access to the Arabic learning became possible. The translations +that were to have influence on Europe were always into Latin. To make +or to obtain such translations many adventurous spirits journeyed from +Christian Europe into Spain, or sometimes into Sicily where conditions +were very similar. These men were aided in their work by native Jews or +by Mohammedans. The heretical company which they kept, together with +the strange and mysterious material which they brought back with them, +earned them a reputation as magicians. The memory, for instance, of +Michael Scot is connected with the Black Art, and has been presented by +Sir Walter Scott in his poem _The Lay of the Last Minstrel_. + +The wizard Michael Scot (died 1235) journeyed in both Spain and +Sicily, learned Arabic and Hebrew, and had commerce with Mohammedans +and Jews. He turned a number of Arabic works into Latin, and, in +particular, he prepared versions of the biological works of Aristotle +(pp. 28-33) which, though corrupt and second-hand, had much influence +in determining the direction of medical thought during the Middle Ages. + +There was a large class of such translators and commentators who made +Arabic Medicine accessible to the West. This Arabic-Latin literature +is generally characterized by the qualities most often associated +with the words _medieval_ and _scholastic_. It is extremely verbose +and almost wholly devoid of the literary graces. An immense amount of +attention is paid to the mere arrangement of the material, which often +occupies its authors more than the ideas that are to be conveyed. +Great stress is laid on argument, especially in the form of the +syllogism, while observation of Nature is entirely in the background. +Above all, there is a constant appeal to the authority of the ancient +masters, especially Aristotle and Galen. Lip service is often paid to +Hippocrates, but his spirit is absent from these windy discussions. + +When the Latin translations from the Arabic reached the readers for +whom they were intended, they were eagerly studied. The texts were, +however, by no means permitted to remain in their pristine state, +but were submitted to exactly the same process to which their Arabic +authors had themselves subjected their Aristotelian and Galenic models. +The Christian writers of the West treated the Latin translations of +Rhazes, of Avicenna, of Isaac and of Albucasis (p. 67), as subjects +for commentary. Their works were expanded, annotated, castigated +again and again, and without any new inflow of ideas. The result is a +progressive elaboration of form and deterioration of content throughout +the centuries. Vast masses of argument, rebuttal, refutation and +confirmation drowned again the human spirit which hardly recovered from +its submersion until the sixteenth century. + + +§ 4. _The Universities._ + +Nevertheless, when these translations were new to Europe, and +especially in the thirteenth century, they caused much stir. In +this awakening a large part was played by the Universities. These +were established in numbers during the thirteenth and the following +centuries. University life gradually came to exercise a profound +effect on social, political and intellectual conditions. In most of +the Universities Medical Faculties grew up. The medical teaching was +entirely theoretical and there was no clinical instruction, though at +the beginning of the fourteenth century some advance was made by the +introduction of brief and superficial anatomical demonstrations (p. 74). + +As a type of Medieval University, we may take Bologna, which was an +important center of learning from a very early date (Fig. 27). As the +Universities multiplied, they began to some extent to ‘specialize’. +Bologna had appeared first as a Law School and continued to develop +along the same line. In the second half of the thirteenth century it +was by far the most important seat of legal learning in Europe. + +An organized Medical Faculty existed there as far back as 1156. The +teaching at Bologna, as in other medical schools, consisted entirely +of readings of Latin translations from Arabic which were becoming ever +more accessible. Yet it was at Bologna that public dissection was first +practised. The early advent of dissection has often impressed the +historian. There was still no botany worthy of the name, no zoology, +hardly any naturalistic art, no experimental science, no systematic +record of observation in any department. Yet dissection had become +recognized at Bologna by the end of the first quarter of the fourteenth +century. The question is why men, so little interested in Nature and +Nature’s ways, should have lent themselves to so repellent a process as +dissection of the human body? The answer is that the earliest reason +for examining the human body was simply the gathering of evidence for +legal processes. As time went on, post-mortem examination passed into +anatomical study. But still dissection did no more, and was asked to +do no more, than verify Avicenna--whom nobody doubted. It was, in fact, +little but an aid to the memory of students. + +At Bologna we can trace the rise of a surgical school beginning about +the end of the twelfth century. Prominent among its early surgeons was +William of Saliceto (1215?-1280?). He wrote a very able treatise on +Surgery, containing a section on Anatomy. The anatomical portion is +borrowed from the current Arabian anatomies, but contains some evidence +of direct access to the dead human body. He includes in his work a good +description of trephining the skull (Fig. 23). + +A most interesting contemporary of William of Saliceto was Thaddeus +of Florence (1223-1303), who also taught at Bologna. This man +perceived the importance of access to Greek sources, as distinct +from Graeco-Arabic, and he encouraged the preparation of good Latin +translations of medical works direct from the Greek. He stamped his +personality on the whole development of Medicine at Bologna, and he +is bound up with the beginning of dissection. But if Medicine owed a +debt to Thaddeus for introducing better texts and better Anatomy, he +did grave harm to the subject in another direction. The scholastic +and argumentative form assumed by medieval Medicine is largely due to +him, and it is to the assumption of this form that we owe the almost +complete absence of scientific advance between the thirteenth and +sixteenth centuries. + +[Illustration: FIG. 27. MEDIEVAL BOLOGNA, from a mural painting of +about 1500 in the town-hall of the city. The city contained a number of +towers, nearly all of which have now been destroyed.] + + +§ 5. _Medieval Anatomy, Surgery and Internal Medicine._ + +At the very end of the thirteenth century there came to Bologna a +Norman student, Henri de Mondeville (about 1270-1320). In 1301 he +settled at the famous Medical School at Montpellier in Southern France, +and thus transplanted to France the medical, surgical and anatomical +traditions of Bologna. Those traditions were of Arabic origin, and +mainly borrowed from Avicenna. + +Contemporary with de Mondeville was one whose method of teaching shines +as a good deed in a naughty world. Mondino di Luzzi (_c._ 1270-1326) +was a pupil of Thaddeus and a fellow-student of Henri de Mondeville. +He worked systematically at Anatomy and dissected the human body +in public. His treatise on Anatomy, written in 1316, is the first +modern work on the subject. Those who preceded him incorporated their +anatomical work in larger treatises on Surgery, and do not refer +directly to their own anatomical experiences. With Mondino this is +changed. His work is essentially a practical manual of the subject +and he is with justice called the ‘Restorer of Anatomy’. He had read +widely among the Arabian anatomists, and naturally borrowed from them. +Nevertheless, his work contains a considerable number of references to +actual anatomical procedure. Moreover, he deals not only with Anatomy +in our modern sense, but also includes Physiology and much discussion +of the application of anatomical and physiological principles to +Medicine and Surgery. His book thus gives a good deal of insight into +the scientific knowledge of the day. + +[Illustration: FIG. 28. AN ANATOMICAL LECTURE AT PADUA in the fifteenth +century, from a contemporary Italian woodcut. + +The professor stands in his ‘chair’, a great pulpit or ‘cathedra’, +reading from his book--hence the English academic titles ‘Reader’ +and ‘Lecturer’ or ‘Lector’ (that is, ‘one who reads’). The body is +dissected by a menial, whose work is guided by an assistant, who, +with wand, points out (Latin _demonstrat_, hence our modern title +_Demonstrator_) the lines of incision. Students in academic dress stand +around, but do not themselves dissect. ] + +We would emphasize the fact that Mondino dissected _in person_. In this +respect he was wiser than his successors until the time of Vesalius. +As dissection gained formal inclusion in the curriculum, the professor +became more haughty, further removed from the object of his study. +Leaving his position by the body, where he might demonstrate to his +students, he ascended his high professorial chair, a great elevated +structure provided with steps and a reading-desk. From there he read +from his text-book while a junior colleague pointed out the line of +incision and a menial performed the actual dissection (Fig. 28). All +was thus done at third-hand and according to the written word. We are +in the scholastic period, and must not expect any frequent appeal to +Nature. Having once got into his chair, it took a good deal to persuade +the professor to descend from that dignified position. Thus, it is +saying much for Mondino that he was his own demonstrator. He took the +first and perhaps the greatest step. It was two centuries and more +before the next step was taken. + +Most typical of medieval surgeons was Guy de Chauliac (1300-68), +who studied at Montpellier, Paris, and Bologna, and practised at +Montpellier and afterwards at Avignon, where he was a member of the +Papal Court. He was a man of much learning, and his _Great Surgery_ +became the standard treatise on the subject during the later Middle +Ages. It fixed medieval practice. It is to be found in scores of +manuscripts and was frequently translated and printed. Among the good +points of his practice is his acceptance of responsibility for certain +operations, such as those for rupture and for cataract, which at that +time were usually left to wandering charlatans who regarded themselves +as specialists. A famous passage in his work describes the use of a +narcotic inhalation frequently used during the Middle Ages and into +modern times. Of such a narcotic it is written that: + + I’ll imitate the pities of old surgeons + To this lost limb, who, ere they show their art, + Cast one asleep, then cut the diseased part. + + (Thomas Middleton, _Women beware women_. First acted 1622.) + +The general character of Internal Medicine during the later Middle Ages +was below that of Surgery. Modern clinical Medicine is firmly based +on such sciences as Physiology, Pharmacology, Pathology, Biochemistry +and Epidemiology. In the Middle Ages and far beyond, Physiology was +still that of Galen, which had lost in exactness what it had gained +in bulk from the Arabic and Latin commentators. Pathology was still +that of the four humors. The knowledge of drugs was empirical, and the +sciences of Pharmacology and Biochemistry as yet were not; while the +medieval conception of the nature of epidemics was the very perversion +of reason and common sense. Nevertheless, as we shall see, the Middle +Ages ultimately succeeded in instituting a limited number of effective +preventive measures. + + +§ 6. _Medieval Hospitals and Hygiene._ + +Undoubtedly an important development of medieval Medicine is its +hospital system. The public hospital arose in pagan antiquity out +of the Temples of Aesculapius and the military valetudinaria (p. +49). The conception was seized on by Christianity and developed +beyond all knowledge. In the early Christian centuries, _hospitalia_, +‘guest chambers’ or ‘guest houses’, were set aside for the numerous +_hospites_, or ‘pilgrims’. Similar buildings under the same title came +to be instituted for the care of orphans, the aged, the blind, and +other victims of fortune. Thus arose the medieval hospital system, of +which ours is the direct outgrowth. + +In matters of Hygiene the Middle Ages are a byword. The health +conditions of a medieval town were far below those of the same town +under the Roman Empire. Water-supply was deficient, drains were +absent, streets and houses filthy and overcrowded, rooms unventilated. +Nevertheless, there is one important hygienic conception for which our +own age owes a considerable debt to that which preceded it. Despite +their scientific acumen in many departments, it is yet true to say +that among the physicians of classical antiquity we find no consistent +view of the transmission of infection by contact. Indeed the whole +idea of infection was effectively absent from them, so that preventive +measures based upon it could not be developed. It was reserved for the +Middle Ages to conceive serious official measures against the spread +of epidemics. These measures were consciously derived from the leper +ritual of the Bible with its fundamental concept of isolation. + +[Illustration: + +FIG. 29. A HOSPITAL WARD in sixteenth century Paris. In the left aisle, +a nun folds the hands of a dying patient, while a priest gives the +Sacrament to another in the same bed. In front, nuns sew shrouds. The +right aisle is more cheerful. Nuns minister to two patients in one bed, +while a convalescent, fortunate in having a bed to himself, vigorously +takes nourishment. In the centre nuns receive postulants and a royal +founder kneels in prayer. + +] + +During the early centuries of the Christian era, Leprosy, which had +till then been confined to the East, crept along the Mediterranean +littoral and thence northward throughout Europe. The disease was +from the first regarded as contagious, and various regulations were +introduced to isolate and separate the unfortunate sufferers. The +medieval treatment of lepers is one of the dark incidents of man’s +inhumanity to man. The leper was banished from human society. He was +declared legally dead. He was excluded even from church or allowed to +attend only in special seats where a special basin of holy water was +assigned to him. How rigorously this segregation from the ranks of free +people was carried out by law is well known. The cruel edicts were, +however, effective. In the course of centuries it freed Europe from +Leprosy, of which it is said there were at one time some 20,000 cases +in France alone. Thus about one person in 200 would have been a leper, +and the burden of the leper on the community was comparable to that, +let us say, of the feeble-minded and insane with us. + +Leper inspection, the regular examination of all suspects and carriers +of leprosy, became a most elaborate business. It was entrusted to +a special branch of the civil service and was gradually freed from +ecclesiastical control. + +This preventive method of combating a chronic disease, which, as we +know now, has a very low infectivity, had a peculiar and unlooked-for +result. The meticulous system of warding off the contagion of leprosy +so occupied the attention of physicians that they came to see allied +conditions in the same light. So it was that in the thirteenth century +the general concept became current of disease as contagious. A number +of other diseases besides leprosy were recognized as infectious. Among +these were Plague, fevers with obvious rashes, Phthisis, Granular +Conjunctivitis, the Itch and Erysipelas. Municipal authorities were +from time to time ordered to put patients suffering from one or other +such diseases outside the city gates. They were forbidden to traffic +in articles of food and drink and were placed under restrictions not +unlike those of lepers. The devastating epidemic of the Black Death of +1347-8 brought restrictions of this order into special force. Thus the +Black Death had somewhat the same effect on the health administration +of the day that the Cholera outbreaks of the thirties of the nineteenth +century had upon modern Europe. The health service began to be put +into more efficient order. + +In the later Middle Ages there were actually instances in which the +Pest was averted or successfully combated by these means. This seems +to have been the case of Milan and Venice between the years 1370 and +1374. At that time the Plague was again advancing through Europe. The +most drastic regulations were invoked to prevent infected persons from +entering the cities, and these regulations came into force well in +advance of the disease. + +There is one incident in this medieval attempt to prevent Plague that +has left a mark on our language. The Republic of Ragusa, on the eastern +side of the Adriatic, adopted and extended the regulations that had +been so successful at Venice. A landing-station was established far +from the city and the harbor. There incoming suspects had to spend +thirty days in the open air and sunlight, and any who had traffic with +them were isolated. The period of thirty days was spoken of as the +_Trentina_. Later this was found to be not long enough. The thirty +days became forty days, the _Quarantina_, whence we have the word +_Quarantine_. The system of quarantine gradually spread through Europe. +It was accompanied by very drastic destruction, by burning, of all +goods belonging to the infected. + +These attempts to arrest epidemic disease were sometimes successful and +the elaboration of quarantine measures was among the few advances with +which we may credit the Middle Ages. The fact that we can now dispense +with quarantine must not blind us to its value in conditions other than +our own. + + + + +IV + +THE REBIRTH OF SCIENCE + +(FROM ABOUT 1500 TO ABOUT 1700) + + +§ 1. _The Anatomical Awakening._ + +During the Middle Ages beliefs about physiology were always based +on Galen. They were frequently confused and often the result of a +misunderstanding of his work. In the fifteenth century, however, took +place the so-called _Renaissance_ or _Revival of Learning_. Greek works +which had been trickling in since the thirteenth century began to be +recovered more rapidly, and to be more accurately studied. The first +step towards any improvement on the views of Galen was naturally a +proper understanding of what he had really said. For that there was +needed a better knowledge of Greek than had been possessed by the +Middle Ages. In the fifteenth century Greek scholarship made great +advances and there was enthusiasm for classical learning. Accurate +translations of the Greek works of Galen were made. The printing press +was invented about the middle of the fifteenth century. Towards its end +printed copies of the improved translations began to appear. So it came +about that the Revival of Learning produced a revival of the ancient +scientific knowledge. + +This scientific revival led to a new interest in Anatomy. During +the Middle Ages the occasional dissections at the Universities were +merely supposed to illustrate Avicenna and Galen (Fig. 28 and p. 72). +Dissection became much more widely practised in the fifteenth century, +but it was nearly the middle of the sixteenth century before any real +and open discussion of Galen’s views took place in the Universities. + +There were, moreover, other influences at work. Along with the revival +of learning there was also a renaissance of art. Some of the great +Renaissance artists--Michelangelo, Raphael and Dürer among them--began +to study the human form very closely. They soon found that to represent +it accurately some knowledge of Anatomy, and especially of the bones +and muscles, was needed. The artists, therefore, began also to dissect. +Among these great artists were some who took more than a purely +artistic interest in the structure and workings of the body. Of these +the most important for us was Leonardo da Vinci (1452-1518). He was a +man of enormously powerful and inquiring mind, and his achievements +in science are at least as remarkable as his works of art. He had +determined to write a text-book of anatomy and physiology. Though he +did not publish it, many of his beautifully illustrated note-books on +these subjects have survived. + +Leonardo was the first to question the views of Galen. He made +careful first-hand investigations on the bodies of men and animals, +and performed many physiological experiments. Though a man of the +most lofty genius, centuries ahead of his time, yet his outlook is, +in many respects, typical of his age. His interest in anatomical +investigation is therefore not surprising, for such inquiries were +then astir. It happened that he was particularly interested in the +heart and blood-vessels. He reached the correct conclusion that, +contrary to Galen, the branches of the air-tubes in the lungs do not +come into relation with the heart, but, after branching and gradually +diminishing in size, they finally end _blindly_. He inflated the lungs +with air and found that, whatever the force used, air could not be +driven from the air-tubes into the heart. He therefore inferred quite +correctly that Galen’s _arteria venalis_ (our ‘pulmonary vein’) did not +convey air to the heart, as the followers of Galen believed. + +Leonardo then turned to examine the structure and form of the heart +itself. He prepared more accurate drawings of it than had been made +by any before him, making sections and dissections and examining its +valves (Fig. 30). Ultimately he succeeded in grasping the nature and +action of the valves at the root of the great arteries as they arise +from the heart, and he verified his view by remarkable experiments. He +proved that the valves allowed the blood to pass in only one direction, +and prevented its regurgitation. Yet Leonardo gives no complete or +clear description of the action of the heart. He could not emancipate +himself from the old idea of the passage of the blood from the right +ventricle through the septum into the left ventricle (Fig. 21), though +he sometimes seems doubtful about it. + +[Illustration: + +FIG. 30. DRAWING OF DISSECTION OF THE HEART by Leonardo da Vinci. The +modern names of some of the more important parts have been added. + +] + +It must be remembered that Leonardo did not publish his researches. It +is only recently that his note-books have become fully accessible. But +although Leonardo’s work remained in manuscript, it must not be assumed +that his views were wholly without effect on his contemporaries. At any +rate, soon after his time the questions that he had raised concerning +the heart and blood-vessels were attracting others and were generally +regarded as forming an important problem needing solution. + +The task of writing an anatomical text-book based on direct +observation, to which Leonardo did but put his hand, was achieved by +one who was only four years old at the time when the great artist +died. The central place in the unfolding drama is occupied by Andreas +Vesalius of Brussels (1514-64). This extraordinary man studied first +at the University of Louvain and afterwards at Paris. Anatomical +instruction at these Universities had not improved much, if at all, on +that of the Middle Ages. Vesalius soon tired of hearing long passages +of Galen read out by the professor. He therefore resolved to go to +northern Italy, where newer methods were being practised. Padua was +the place of his choice. He immediately made his mark there, and was +himself appointed professor when only twenty-four years of age. He +established a scientific tradition at Padua which that University has +retained to this day. + +No sooner was Vesalius settled at Padua than he applied himself with +unparalleled diligence to lecturing and research. Students crowded +to hear him (Fig. 31). To aid them he issued, in 1538, a short guide +to anatomy and physiology. An examination of this shows that his +physiological views were still those of Galen and Aristotle. After its +issue Vesalius found that Galen and Aristotle were by no means always +to be trusted. The realization of this led him constantly to doubt any +statement by them. His scepticism was sometimes excessive, but it led +him to put every statement made by his predecessors to the test of +experience. This gives his later work an epoch-making value. + +[Illustration: FIG. 31. TITLE-PAGE of the work _On the Fabric of the +Human Body_, by Vesalius, published in 1543. + +It shows a dissection scene at Padua. In the center stands Vesalius +dissecting a female body. At the head of the table stands an +articulated skeleton. At its foot are dissecting instruments. Eager +students throng around. In the foreground attendants are squabbling. +On one side an attendant holds a monkey, one on the other a dog, for +Vesalius had often to resort to animal in lieu of human anatomy. Shut +off by a bar are members of the lay public. Gallants, grey-bearded +scholars, monks, and an enthusiastic bookworm may be discerned among +them. Other observers crowd in from every vantage point, even from +the windows in the roof. The naked man to the left has been used by +Vesalius to demonstrate the surface markings of the underlying organs. +The whole scene is busy and vigorous in the extreme. It should be +contrasted with the academic calm of Fig. 28 drawn fifty years earlier. +] + +During the next four years Vesalius had ampler opportunities to +dissect than he had yet encountered. He devoted a fiery energy to the +preparation of his great work. _The Fabric_ (that is ‘workings’, +compare German ‘Fabrik’) _of the Human Body_ was printed in 1543, a +magnificent and beautifully illustrated volume. It is a landmark in +the History of Science, and a wonderfully full record of a prodigious +number of accurately recorded discoveries and investigations made by a +single observer. + +The masterpiece of Vesalius is not only the foundation of modern +Medicine as a science, but the first great positive achievement of +Science itself in modern times. As such it ranks with another work that +appeared in the same year, the treatise of Nicholas Copernicus, _On the +Revolutions of the Celestial Spheres_. The work of Copernicus removed +the Earth from the center of the Universe; that of Vesalius revealed +the real structure of man’s body. Between the two they destroyed for +ever the medieval theories on the subjects of which they treat. But +the work of Copernicus is one of close and subtle reasoning, still +retaining many medieval elements, and is hardly a great exposition +of what we now call the ‘Experimental Method’. The work of Vesalius +far more nearly resembles a modern scientific monograph than does the +treatise of Copernicus. + +The achievement of Vesalius was very well received by the scientific +world. Nevertheless, soon after its publication, Vesalius resigned +his professorship to take up the position of a court physician to the +Emperor Charles V, the great monarch of the age. He was then only +twenty-nine years old, but his scientific career was closed. + +The edition of the _Fabric_ was soon exhausted, and the demand for +more copies was met by imitations of the work by other hands. At last, +in 1555, Vesalius was induced to issue a second edition. This contains +certain changes in point of view that are important for the subsequent +development of physiology. Vesalius now no longer merely hints his +doubts as to the character of Galen’s physiology; he openly asserts +that he is unable to verify its fundamental bases. + +We may take a single instance of this new outspokenness. In his +description of the septum of the heart, he had written in the first +edition: + + ‘The septum of the ventricles of the heart is very dense. It + abounds with pits on both sides. Of these pits none, so far + as the senses can perceive, penetrate from the right to the + left ventricle. We are thus forced to wonder at the art of the + Creator, by which the blood passes from right to left ventricle + through pores which elude the sight.’ (Compare Fig. 21, p. 59.) + +This passage is altered to something quite different in the second +edition, where he writes: + + ‘Although sometimes these pits are conspicuous, yet none, so + far as the senses can perceive, passes from the right to the + left ventricle. I have not come across even the most hidden + channels by which the septum of the ventricles is pierced. Yet + such channels are described by teachers of Anatomy, who have + absolutely decided that the blood is taken from the right to + the left ventricle. I, however, am in great doubt as to the + action of the heart in this part.’ + +He further sets forth his whole policy with reference to Galen’s view +in the following interesting passage: + + ‘In considering the structure of the heart and the use of its + parts, I bring my words for the most part into agreement with + the teachings of Galen; not because I think these on every + point in harmony with the truth, but because, in referring at + times to new uses and purposes for the parts, I still distrust + myself. Not long ago I would not have dared to diverge a hair’s + breadth from Galen’s opinion. But the septum is as thick, dense + and compact as the rest of the heart. I do not, therefore, see + how even the smallest particle can be transferred from the + right to the left ventricle through it. When these and other + facts are considered, many doubtful matters arise concerning + the blood-vessels.’ + +The work terminates with a little chapter _On the dissection of living +animals_. We note that this, while dealing skilfully with the methods +of physiological experiment, does not exhibit any very marked advance +on the views of Galen. + +Among the experiments on living animals that Vesalius enumerates are +excision of the spleen, the loss of which he showed was consistent +with life; and the cutting of the nerves that supply the organ of +voice, with resultant loss of that faculty. He demonstrated that +longitudinal section of a muscle interferes little with its function, +but cross section produces disability in proportion to the injury. +Such experiments had been performed by Galen, who had also reached the +same conclusion as Vesalius, that it is through the spinal cord that +the brain acts on the various muscles of the limbs and trunk. Vesalius +repeated Galen’s experiments on section of the spinal cord (p. 58). The +most striking of his experiments were those on respiration. Here he +showed that, even though the chest-wall be pierced, the animal may be +kept alive if the lungs are continuously aerated by means of a bellows, +and that a flagging heart may be revived by similar means. + +The work of Vesalius at once placed the knowledge of the human body +in a new position. It cannot be said that he completed the task of +describing the naked-eye structure of the human body. Yet he went so +far towards this that no dramatic improvement has since been made +upon his methods. It is a fair statement that the whole of modern +Descriptive Anatomy may be treated as a comment and correction and +amplification of Vesalius. His work moreover stimulated a host of +investigators. + +[Illustration: FIG. 32. SKELETON from the anatomical work of Vesalius, +1543. + +It is beautifully and dramatically posed, and the drawing is remarkably +accurate. The figure leans against a tomb, contemplating a skull. In +the front left-hand corner of the top of the tomb is a part of the bony +structure which supports the organ of voice (H). + +The inscription on the tomb may be translated ‘Man’s spirit lives. The +rest is Death’s portion’. + +The inscription at the top may be translated: ‘A delineation from the +side of the bones of the human body, freed from the other structures +which they support and placed in their correct positions.’ ] + + +§ 2. _The Anatomical Reaction on Surgery._ + +The immediate effect of the new knowledge of Anatomy was an improvement +in Surgery. The Wars of Religion of the sixteenth and seventeenth +centuries were fierce and prolonged, and the army surgeons of the time +had much experience of the treatment of wounds. The most prominent of +the military practitioners was the Frenchman, Ambroise Paré (1517-90). +He perceived the importance of anatomical knowledge and adapted his +discoveries to the needs of Surgery. Paré did much to elevate the +surgeon’s profession from a despised handicraft to a position equal to +that of other branches of the healing art. + +Apart from the introduction of anatomical discipline into Surgery, +Paré’s four contributions to the surgical art were, firstly, his +discovery that gunshot wounds are not ‘poisonous’ as had theretofore +been thought, and that therefore they do not require the application +of boiling oil, but are best healed by soothing applications; +secondly, the cognate doctrine that bleeding after amputations should +be arrested, not by the terrible method of indiscriminate use of the +red-hot cautery, but by simple ligature; thirdly, his advocacy of +the method of turning the child in its mother’s womb before delivery +in certain abnormal cases; and fourthly, his ingenious devising of +artificial limbs (Fig. 33). None of these four was without precedent. +Nevertheless, the eminence, skill, and wide experience of Paré were +the main factor in the spread of these practices. But the greatest +of all Paré’s contributions to surgery was the service of his own +personality, the example of his steadfast efforts to increase his +knowledge of human anatomy and his skill in the art, and his constant +emphasis on the surgeon’s duty to exert his utmost efforts to avoid or +relieve the patient’s suffering. + +[Illustration: + +FIG. 33. ARTIFICIAL ARMS AND HANDS, designed and figured by Ambroise +Paré, and used by him for wounded soldiers from about 1560 onwards. + +] + +In a famous passage Paré describes how he, a ‘freshwater soldier’, on +his first campaign, watched the other surgeons following the old rule +of treating all gunshot wounds with boiling oil. At first he formed +his practice on theirs. The theory was that gunshot wounds contained a +poison, which the boiling oil was believed to drive out. Paré tells of +his agitation when one evening, his supplies having run out, men had to +be treated without the boiling oil. Next morning he was astonished to +find that every man whose wounds had been treated only with a salve had +rested fairly comfortably, while all who had undergone the customary +treatment were, as we may well believe, in great pain. ‘Then I resolved +within myself never so cruelly to burn poor wounded men.’ Another +saying of the shrewd old surgeon is the famous adage ‘I dressed him and +God cured him.’ + +Paré’s works were frequently reprinted and translated into various +European languages, including English. They exercised the widest +influence on surgical craft in the sixteenth and seventeenth centuries. +Like Vesalius, he is an example and type of a large class. In every +country surgeons arose who made an effort to utilize the new anatomical +knowledge. + + +§ 3. _The Renaissance of Internal Medicine._ + +Internal Medicine lagged behind Surgery at this period. The anatomical +reforms of Vesalius were unaccompanied by any commensurate advance in +physiological knowledge, and without a scientific Physiology there can +be no science of Internal Medicine. The practice of the physicians thus +remained in effect that of the Middle Ages. The ruling idea was still +that of the ‘four humors’ corresponding to the four ‘temperaments’ +(Fig. 13, p. 34, and compare Fig. 34, p. 97). + +There are, however, three respects in which we see an improvement +of the physician’s art during the sixteenth and first half of the +seventeenth century. + +Firstly, there was some improvement in the medical texts that were +habitually read. More reliable translations were now available. Notably +the great Hippocratic works became more widely disseminated. They +formed a substitute for the old texts translated or mistranslated from +the Arabic. + +Secondly, the extension of geographical knowledge and the formation +of settlements and colonies brought new drugs upon the market. These +were often a mixed blessing, for some of the drugs were useless and +others dangerous. Nevertheless, to this process Medicine owes several +important contributions, among them Ipecacuanha, Cinchona (p. 326), +and, by no means least, Tobacco (Fig. 35). Apart from the amenities +introduced by Tobacco, it was for long of great value as a narcotic +drug. Moreover, there was a corresponding advance in Botany. The +movement was cursed with the ‘practical’ spirit, and only those plants +thought to have an application as drugs were exactly figured and +described. Nevertheless, the beautifully illustrated herbals of the +sixteenth and seventeenth centuries exercised, by the care and accuracy +of their execution, an exemplary influence on the development of +Biological Science in general and of Medical Science in particular. + +Thirdly, there was some advance in the knowledge of the natural history +of infectious disease. A rational theory of the nature of infection was +placed before the public as early as 1546 by the Veronese physician, +Girolamo Fracastoro (1483-1553). He regarded infection as due to the +passage of minute bodies from the infector to the infected. These +hypothetical minute bodies had the power of self-multiplication. The +conception bore a superficial resemblance to the modern germ theory of +disease. An important contribution to the conception of epidemics was +also made by the French physician Guillaume de Baillou (1538-1616), +who reintroduced the old Hippocratic idea of ‘Epidemic Constitution’, +i.e. that particular seasons and particular years are of their nature +subject to particular diseases. The idea was extended and developed by +the English physician Thomas Sydenham (1624-89), and it still has its +value. + +[Illustration: + +FIG. 34. FIGURE ILLUSTRATING THE ‘FOUR TEMPERAMENTS’, from the Guild +Book of the Barber-Surgeons of York, now in the British Museum. The +figure was prepared about 1500. Above, to the left, is the _Melancholy_ +man, and to the right the _Sanguine_. Below to the left is the +_Choleric_ man, and to the right the _Phlegmatic_. On the scroll work +is written in English ‘Ther ar the iiij umors, thath ar oderwysse calde +the iiij complecconis thath ar resceuid un to the iiij elementis, +Hafyng the kynd of humors’, which may be rendered ‘There are the 4 +humors, that are otherwise called the 4 complexions, that are received +unto the 4 elements, having the nature of humors’. For the theory +compare Fig. 13, p. 34. + +] + +In connection with their epidemiological work these three men, +Fracastoro, de Baillou, and Sydenham, made significant additions to +the knowledge of particular infectious conditions. Thus, during the +sixteenth and seventeenth centuries there arose an exact body of +teaching concerning acute infectious diseases which was the necessary +prelude to the introduction of more effective preventive measures at +a later date. To one infectious disease we may refer more particularly. + +During the Middle Ages there had smouldered in various districts an +obscure disease, sometimes more or less dimly distinguished under +various specific names, but most frequently confused with Leprosy. +Towards the end of the fifteenth century this disease, which was still +imperfectly distinguished in men’s minds from Leprosy, broke out in +epidemic and virulent form all over Europe. It caused great destruction +of life and developed everywhere as a problem of national importance. +Various titles were given it, such as ‘pox,’ ‘the French disease’, ‘the +Spanish disorder’. Only tardily was it recognized that the disease +was usually of venereal origin. Not till 1530, on the suggestion of +Fracastoro, did it receive its modern cognomen _Syphilis_. From the +time of its recognition, Syphilis has been pursued by a portentous +mass of literature, the mere sifting and verification of which is a +formidable task. Alarm, misunderstanding, religious feeling, false +modesty, wilful misrepresentation, and change in type of the disease +itself have all contributed their quota of obscurantism and fable to a +naturally difficult subject (Figs. 35 and 36). Fracastoro did something +to bring order out of the confusion. To him also we owe the first good +scientific descriptions of several other destructive diseases, among +which Typhus fever, now known to be conveyed by lice (p. 258), takes a +prominent place. + +[Illustration: + +FIG. 35. THE EARLIEST PICTURE showing the use of Tobacco. From a +work on Brazil, printed in Paris in 1558. In the center of a native +hut stands an Indian suffering from Syphilis. Behind him, on the +left, a man smokes a huge cigar over him as a curative measure. +Right and left his arms are held by two figures who seek to suck +the poison out of him. Another offers him a curative plant. Behind +him is a ‘hammock’--the word is of American-Indian origin and means +‘tobacco-bed’. Above his head are a monkey, a parrot, and a bale of +tobacco. + +] + +De Baillou (1538-1616) first described Whooping Cough, and was the +first to use the word _Rheumatism_ in the modern sense. He was moreover +the first, since Hippocrates, to distinguish between Rheumatism and +Gout. De Baillou’s works deeply influenced Sydenham, who held very +similar epidemiological views, and uses a somewhat similar vocabulary +(p. 100). + +We have seen how the knowledge of Anatomy forwarded Surgery, while, +with the lag in Physiology, Internal Medicine remained in a backward +state. It is well to recall however that a knowledge of Anatomy and +Physiology will not, of themselves, make a man a scientific physician. +The object which presents itself to a physician is neither a living +anatomy nor a physiological model. It is a sick and suffering patient. +The physician’s first task is to examine exactly the phenomena of +sickness and suffering, and in doing this the first demand on his +knowledge will be the history and fate of others who have endured like +sickness and suffering. When he has ranged these instances in his mind +he may turn, for explanation and relief, to the resources suggested +by other sciences, Anatomy and Physiology among them. But all the +Anatomy and Physiology in the world will not aid the practitioner who +is unacquainted with the natural history of disease. This is the truth +that was firmly seized by Thomas Sydenham. + +The Natural History of Disease was a subject which Sydenham pursued +with lifelong devotion. Before his time the phenomena of disease had +been classified, subdivided, discussed, and treated with all the +subtlety and skill of scholastic thought. Men had now and again shaken +themselves free from the shackles of the medieval system, and had +here and there corrected the views of Galen or amplified the limited +achievements of their predecessors. Yet none before Sydenham had set +himself to consider all the actual cases of disease that lay before him +as a subject of scientific description and analysis. That was the great +achievement of the ‘English Hippocrates’. We should not find it easy +to point to any important discovery to associate with his name. But he +did more than discover. He initiated a new mode of approach. He was the +founder of modern Clinical Medicine. + +In 1666 Thomas Sydenham published his classic work, _The Method of +Treating Fevers_, dedicated to his friend Robert Boyle, ‘the Father +of Chemistry’ (pp. 124-6). The book opens with the almost Hippocratic +phrase ‘A disease, in my opinion, how prejudicial soever its cause may +be to the body, is no more than a vigorous effort of Nature to throw +off the morbific matter, and thus recover the patient’. We have here +the _healing power of Nature_ of Hippocrates (p. 21), which had been +obscured and overlaid in the twenty centuries which lay between the +two great physicians. The works of Sydenham may reasonably be regarded +as the first great commentary on the Hippocratic theme. Sydenham set +well on its way the conception of infectious conditions as specific +entities, a conception which has since been illuminated by the germ +theory of disease (p. 224 ff.). + +[Illustration: FIG. 36. Allegorical picture illustrating the venereal +plague Syphilis. + +From a work printed in Germany in 1496. The Virgin sits enthroned on +clouds, crowning a crusader, who kneels at her right hand. The Holy +Child on her knee sends forth the plague of Syphilis as a scourge on +mankind. Two women, spotted with the rash of the disease, kneel in +supplication before her on her left. In the foreground of the picture +lies a corpse dead of the disease, the speckled ravages of which may be +seen upon it. + +] + + +§ 4. _The First Physical Synthesis._ + +Manifestations of the Human Spirit are not accustomed to confine +themselves exactly within the convenient limits of the centuries. +Nevertheless, it happens that in the History of Science the year 1600 +does, in fact, correspond to something of the character of a real +change in the current attitude to Nature. That year really ushers in +the era of physical experiment. The last of the great transitional +thinkers who mark the waning of Renaissance philosophy was Giordano +Bruno, the martyr of science. + +Giordano Bruno (1548-1600), who was no practical scientist, had eagerly +incorporated into his often fantastic philosophy the ill-worked-out +conclusions of Copernicus (p. 88). Nominally adopting the Copernican +theory, he modified it fundamentally. Copernicus, having placed the Sun +at the center of the World, and made the Earth and other planets circle +round it, had still left the stars at a fixed and definite distance, as +had the ancient astronomers. The limitation of the sphere of the fixed +stars was obnoxious to Giordano, and he removed the boundaries of the +Universe to an infinite distance, in accordance with the principles +of his philosophy. The change may seem unimportant save for astronomy, +but, in fact, it came to influence every department of scientific +thought, for the endlessness of Nature is implicit in the modern +scientific attitude. + +Giordano was burned at the stake at Rome, after seven years’ +imprisonment, in 1600. In the same year the experimental era was +ushered in with the work of William Gilbert (1544-1603), _On the +Magnet_, in which he not only demonstrates experimentally the +properties of magnets but also shows that the Earth itself is a magnet. +In the same year, too, Tycho Brahe (1546-1601) handed over the torch to +Johannes Kepler. Tycho was the last of the older astronomers who worked +on the Aristotelian view of circular and uniform movements of heavenly +bodies. Kepler was the real founder of the modern astronomical system. +The period from 1600 onward lies with new men, Galileo (1564-1642) and +Kepler (1571-1630) among astronomers and physicists, Harvey (1578-1657) +among biologists, Descartes (1596-1650) among philosophers. + +The seventeenth century opened with an extraordinary wealth of +scientific discovery. As we glance at the mass of fundamental work +produced during that period, we perceive the major departments of +Science, as we know them to-day, becoming clearly differentiated. +The acceptance of Observation and Experiment as the only method of +eliciting the Laws of Nature reaches an ever-widening circle. Even +to enumerate the names of the seventeenth-century pioneers would be +a formidable task. The sciences penetrated to the Universities and +influenced the curricula. The number of scientific men became so large +and so influential that separate organizations were formed by them in +the interests of their studies. It is the age of the foundation of the +‘Academies’, of which the English Royal Society is a type. + +From the multitude of workers on these subjects we can but select a few +names. In the first half of the century Galileo and Kepler are the main +exponents of natural law. Descartes takes his place here as the first +since antiquity who sought to explain the phenomenal universe on a +unitary basis. In the second half of the period comes the mighty figure +of Newton, whose researches ushered in that phase in our story in which +we live to-day. + +The early training of Galileo Galilei had been scholastic and +Aristotelian. By 1590, however, he had begun to doubt, and was making +experiments on the rate of acceleration of falling bodies. His +conclusions were demonstrated in 1591 from the leaning tower of Pisa. +By that famous experiment he showed, in the most public manner, the +error of the Aristotelian view that the rate of fall was a function not +of the weight of the object but of the period of fall. Revolutionary +also was Galileo’s work of 1604. In that year a new star appeared in +the constellation _Serpentarius_. He demonstrated that this star was +situated beyond the planets and among the remote heavenly bodies. +Now this remote region was regarded in the Aristotelian scheme +as absolutely changeless. Although new stars had been previously +noticed, they had been considered to belong to the lower and less +perfect regions nearer to earth. To the same lower region, according +to the then current theory, belonged such temporary and rapidly +changing bodies as meteors and comets. But Galileo had attacked the +incorruptible and unchangeable heavens. + +In 1609 Galileo made accessible two instruments that were to have a +deep influence on the subsequent development of Science, the Telescope +and Microscope. It is with the former instrument that his name is most +frequently associated. His first discoveries made by means of the +Telescope were issued in 1610. That year was crowded with important +observations especially on the inner planets and notably on Venus. It +had been rightly claimed in criticizing the Copernican hypothesis that, +if the planets resemble the Earth in revolving round the Sun, only such +parts of them should be luminous as are exposed to the Sun’s rays. In +other words, they should exhibit phases like the Moon. Such phases in +Venus were now actually observed by Galileo. In the following year he +described sunspots and traced them round the Sun’s disk. + +We need not follow the further astronomical observations of Galileo, +nor need we discuss the contest with the older school on which he +embarked. It is sufficient to remind ourselves that the appearance +of a new star, the behavior of the rings of Saturn, the observations +of the phases of Venus and of the Sun’s spots, struck a blow at the +Aristotelian astronomy comparable to that delivered against the +Aristotelian physics by the falling weights from the leaning tower of +Pisa. Aristotelian astronomy demanded heavens eternally changeless. +Here were changes and new appearances in the heavens, clearly visible +to all who would see. + +During these years too, Galileo was laying firm the foundations of the +science of Mechanics. Out of his mechanical researches came a new way +of looking at the objects of Nature which has profoundly influenced +the entire subsequent course of science. That way is best expressed +in Galileo’s own words, which place him among the philosophers whose +thought influences all those who deal with scientific themes. + + ‘As soon as I form a conception of a material or corporeal + substance, I simultaneously feel the necessity of conceiving + that it has boundaries and is of some shape or other; that + relatively to others it is great or small; that it is in this + or that place, in this or that time; that it is in motion or + at rest; that it touches, or does not touch, another body; + that it is unique, rare, or common; nor can I, by any act of + imagination, disjoin it from these qualities. But I do not find + myself absolutely compelled to apprehend it as necessarily + accompanied by such conditions as that it must be white or + red, bitter or sweet, sonorous or silent, smelling sweetly + or disagreeably; and if the senses had not pointed out these + qualities language and imagination alone could never have + arrived at them. Therefore I think that these tastes, smells, + colors, &c., with regard to the object in which they appear to + reside, are nothing more than mere names. They exist only in + the sensitive body, for when the living creature is removed + all these qualities are carried off and annihilated, although + we have imposed particular names upon them, and would fain + persuade ourselves that they truly and in fact exist. I do + not believe that there exists anything in external bodies for + exciting tastes, smells and sounds, &c., except size, shape, + quantity, and motion. If ears, tongues, and noses were removed, + I am of opinion that shape, quantity, and motion would remain, + but there would be an end of smells, tastes, and sounds, which + abstractedly from the living creature I take to be mere words.’ + +This passage is a veritable Charter of Science. From Galileo’s day to +ours, men of science have occupied + +themselves in measuring size, shape, quantity, and motion, the +‘primary qualities’, and expressing their knowledge in that measured +form. They have relegated colors, smells, tastes, sounds, and other +sense-impressions to the position of ‘secondary qualities’, and have +tried to express them, when they express them at all, in terms of the +primary qualities. We need not enter on the philosophical discussion +as to how far the primary qualities are in truth more real than the +secondary, but it is a fact that, since the time of Galileo, Science +has come to be regarded more and more widely as an exact process. +_Science is Measurement._ It is a conception that has affected the +medical no less than the other sciences, and it is a conception that +Medicine, for good or ill, owes to Galileo. + +[Illustration: + +FIG. 37. SANCTORIUS IN HIS BALANCE. Sanctorius was able to eat and +even to sleep in his balance, counterpoised by a weight working on +the principle of the steelyard. He was thus able to test his weight +under various conditions, and notably to estimate the amount of +the ‘insensible’ perspiration. His were the first experiments on +‘Metabolism’ (see p. 108). + +] + + +§ 5. _The Revival of Physiology._ + +The first to apply Galilean principles of measurement to biological +matters was Sanctorius (1561-1636), a professor at Padua. He described +a thermometer for use in taking the temperature of the human body +(Figs. 39 and 40), and an apparatus for comparing the rate of pulse +beats (Fig. 41). Both these he modified from devices suggested by +Galileo (Fig. 38). It is an indication of the transitional character +of the Science of the time that he describes these instruments in a +commentary on a medieval translation of the _Canon_ of Avicenna (p. +67). He also sought to compare the weight of the body at different +times and in different circumstances. In the process of doing this, he +demonstrated that the body loses weight by mere exposure, a process +which he ascribed to ‘insensible perspiration’ (Fig. 37). By these +experiments he laid the foundation of the modern study of ‘Metabolism’ +(p. 220). + +[Illustration: + +FIG. 38. The principle of Galileo’s thermometer. A tube ending in a +bulb A is inverted over a mercury bath B. If the temperature fall the +air in A will contract and mercury be drawn up into the tube. If the +temperature rise the air in A will expand and mercury be driven out +of the tube. The height of the mercury can be read on the scale SS. +The reading will not be accurate because the instrument is, in fact, +also a barometer, since the mercury in B is exposed to the atmospheric +pressure, which will therefore affect the rise in the tube. + +FIG. 39. The application of the same system by Sanctorius who used a +curved tube. + +FIG. 40 is not, as might be thought, a man trying to swallow a +centipede, but the adaptation of the instrument of Sanctorius as a +clinical thermometer. + +FIG. 41. Galileo’s simple and effective ‘pulsimeter’. It consists only +of a weight suspended on a thread. This thread is held in the hand and +the weight made to oscillate as a pendulum. As the thread is shortened +the oscillations increase in frequency. The process is continued until +the pendulum oscillates to time with the pulse. The length of the free +thread is then read off on the accompanying scale. It was used by +Sanctorius. + +] + +While Sanctorius was engaged in this pioneer work at Padua, the +movement that Vesalius had inaugurated there was making further +conquests in the purely biological line. Vesalius had been succeeded +at Padua by a series of anatomists of great eminence. Perhaps the +most prominent among these was Jerome Fabricius (1537-1619), usually +called ‘of Aquapendente’, after the small Tuscan village where he +was born. This Fabricius of Aquapendente taught at Padua for over +fifty years, from 1565 till his death at eighty-two in 1619. He made +many contributions to the advancement of anatomy, most of which had +physiological bearings. Thus, he was the effective founder of modern +embryology and the author of the first illustrated work on that +subject, in which he describes the formation of the chick in the egg. +He was the first to give accurate figures of the structure of the +eye. He developed the mechanics of muscular motion. He added to his +qualities as an observer the power of attracting younger men. + +In spite of all his powers, however, Fabricius never shook himself free +from ancient views, and especially he was steeped in the theories of +Aristotle and Galen. This backward-looking habit prevented his work +from being as important as it might otherwise have been. In connection +with the circulation, for instance, he made a striking discovery, but +wholly failed to draw out its most important lesson. + +[Illustration: + +FIG. 42. DISSECTION OF A VEIN in the thigh and leg from a work _On the +Valves of the Veins_, published by Fabricius in 1603 at Padua. These +valves prevent the passage of the blood in any direction except toward +the heart. They may be seen at the points P, Q, R, S, and T. + +] + +In 1600 he published his book, _On the Valves of the Veins_. In it he +says that these structures are so placed that their mouths are always +directed _toward_ the heart (Fig. 42), yet he never gets an inkling +that the effect of these valves must be to prevent blood flowing +into the veins except toward the heart. He is too set on the old +Galenic physiology to permit such a revolutionary thought. The real +importance of Fabricius is, therefore, not so much as an investigator +but rather as a teacher, a capacity in which he shone above all other +physiologists for generations to come. He would deserve our remembrance +if only as the master of the discoverer of the circulation of the +blood, William Harvey. + +The Englishman, William Harvey (1578-1657), after education at +Cambridge, went to Padua in 1599, when Fabricius was at the height +of his powers. Returning to England in 1602, he set up in practice +in London. During the years which followed, he was dissecting and +experimenting very industriously, and by 1615 had reached a clear +conception of the circulation of the blood (Fig. 43), though he did not +publish his discovery till some thirteen years later. + +To discuss the actual steps by which Harvey made his discovery +would be beyond our scope. He had, however, been well trained in +experimenting on living animals by Fabricius, and had read widely in +anatomical literature. He was of a contemplative turn of mind and +his quiet and cautious temper, united with his enthusiasm and skill +as an experimenter, provided a superb mental equipment for a life of +scientific investigation. + +Harvey, early in his work, reached two fundamental conceptions +concerning the vascular system. He perceived that the valves in the +veins would permit the blood to pass only towards the heart (Fig. +43), while those in the great arteries arising from the heart would +permit the blood to pass only away from the heart. In connection with +the movement of the blood, Harvey’s crucial point is that it must be +_continuous_, and _always in one direction_. This really clinches +the matter, for consider the capacity of the heart. Let us suppose +that either ventricle holds but 2 ounces of blood. The pulse beats 72 +times a minute and 72 × 60 times an hour. In the course of one hour, +therefore, the left ventricle will throw into the aorta, or the right +ventricle into the pulmonary artery, no less than 72 × 60 × 2 = 8,640 +ounces = 38 stones 8 lb. In other words, in one hour the ventricle will +throw into the great artery more than three times the body weight of +a heavy man. Where can all this blood come from? Whither can it all +go? It cannot come from the ingested food and drink, for no one could +consume so much in one hour! It cannot reach and remain in the tissues, +for they would soon all burst and ooze with blood! The solution of the +puzzle, Harvey came to see, is that it is the same blood that is always +being pumped into the arteries, and the same blood that is always +coming back through the veins. In other words the blood _circulates_, a +fact which Harvey proceeded to demonstrate with convincing thoroughness +(Fig. 43). + +[Illustration: + +FIG. 43. DIAGRAM TO ILLUSTRATE THE NATURE OF THE CIRCULATION OF THE +BLOOD. Leaving the _left ventricle_, when the walls of that cavity +contract, the blood is forced through the valves into the great artery +known as the _aorta_. From the aorta it passes into smaller and ever +smaller arteries, finally reaching the _systemic capillaries_ or the +_portal capillaries_. After travelling through one or other capillary +network it enters a vein. Thence it passes into larger and ever larger +veins, until it ultimately enters the great vein known as the _vena +cava_ that opens into the _right auricle_. It has now completed the +Greater Circulation. As the right auricle contracts the blood passes +through the valves between the right auricle and right ventricle into +the _right ventricle_. From there it enters the Lesser Circulation, +passing into the great _pulmonary artery_, which conducts it to the +lung. In the lung the pulmonary artery breaks up into branches and +finally into capillaries. Through these the blood travels until it +reaches a tributary of the _pulmonary vein_ and finally the pulmonary +vein itself. The pulmonary vein empties its blood into the _left +auricle_. From the left auricle the blood passes at last into the left +ventricle from which it started, having traversed both the Greater and +the Lesser Circulations. + +To understand the change which Harvey wrought in the conception of the +workings of the body, this description and diagram should be compared +with the description and diagram on pages 56-59. + +] + +We may note that, though Harvey demonstrated the existence of the +circulation, he was never able to follow it throughout, for he did not +see the capillary vessels by which the blood is conveyed from the +terminal branches of the arteries to the smallest tributaries of the +veins. These were first demonstrated by Malpighi (p. 116). + +The knowledge of the circulation of the blood has been the basis of +the whole of modern Physiology and with it of the whole of modern +rational Medicine. The attitude of Galen and Aristotle towards the +heart and the great vessels passed into the shadow. The blood, it was +seen, is a carrier always going round and round on the same beat. What +it carries, and why, how and where it takes up its loads, and how, +where, and why it parts with them, these are questions the answering +of which has been the main task of Physiology in the centuries that +have followed. As each of the questions has obtained a more and more +rational answer, so clinical Medicine has always made a step forward, +and has come to approach more nearly to a true science. Thus it is that +the work of Harvey lies at the back of almost every important medical +advance. + +[Illustration: + +FIG. 44. THE VALVES in the superficial veins as seen in the bandaged +arms of living men, from William Harvey’s great work on the +_Circulation of the Blood_, printed in 1628. The bandage is seen on the +upper arm in each case, and the valves are indicated, as in life, by +nodes or swellings in the veins. If a finger is pressed along the vein +from one valve to another as from node O to node H in a direction away +from the heart, the vein from O to H will be emptied of blood. It will +remain empty, since the valve at O does not permit the passage of blood +away from the heart, but only towards it. This observation was Harvey’s +starting point for his great discovery. + +] + + +§ 6. _Microscopic Analysis of the Animal Body._ + +The compound microscope was first made into an effective instrument by +Galileo. It was, as it were, a _by-product_ of his invention of the +telescope. With that instrument he had seen enough to convince himself +that the movement of the Sun round the Earth was but an appearance. +At the very time that Harvey was giving his first course of lectures +securely in London, Galileo’s teaching was attracting the unwelcome +attention of the Inquisition in Rome. + +Galileo’s microscopes, however, were far less satisfactory than his +telescopes. For optical reasons which we need not discuss, these early +compound microscopes failed to give a clear picture. With any high +degree of magnification, the image was always blurred and distorted. +More than three centuries were to pass before a better compound system +was introduced. But about 1650 a way was found of constructing and +mounting simple lenses of very high power. Many of the most important +microscopical discoveries of the second half of the seventeenth +century were, therefore, made with a simple lens. This was notably +the case with much of the work of the great investigators Malpighi and +Leeuwenhoek (Fig. 49 A). + +[Illustration: + +FIG. 45. LUNGS OF FROG, showing the capillary vessels from a figure +by Malpighi in the rare first edition of his work _On the Lungs_, +published at Bologna in 1661. A is the part of the larynx, B is the +opening of the larynx into the trachea or air-tube leading to the lung. +The letters EEE represent the outer surface of the lung and exhibit +the network of capillary vessels. On the other side the sack-like lung +has been laid open, and is viewed from the inside. The letters HHH are +placed upon veins on the inner surface of the lung. These arise from +capillaries which are indicated between the veins. + +] + +Marcello Malpighi (1628-94) was born in the year in which Harvey’s work +was published. He became a professor at Bologna, having early developed +great skill in minute investigation. His first work, which appeared in +1661, supplied the element missing in the investigations of Harvey, +for he describes the actual passage of blood from the arteries to the +veins through the ‘capillary’ blood-vessels (Fig. 45). Harvey, who +did not use a microscope, knew nothing of the capillaries. The object +which yielded up the secret was the lung of the frog. This organ in the +frog happens to be almost transparent, is very simple in structure, +and is furnished on its surface with particularly conspicuous capillary +vessels. Malpighi could hardly have selected an object better suited +for this particular research. This important discovery of his drew the +attention of scientific men in England. The Royal Society soon entered +into correspondence with him, and during the remainder of his life +undertook the publication of his researches. + +[Illustration: In 1673 Malpighi published in London his work _On the +Formation of the Chick in the Egg_. Thirteen years later, in 1686, he +published extensions and corrections of this work. Our figures are +taken from the later work. + +FIG. 46 is the whole embryonic area, at about the end of the second day +of incubation. The embryo itself is seen with its large head containing +the three ‘cerebral vesicles’ (which are the rudiments of the brain), +the large eye, the protuberant coiled heart (NM), from which vessels +pass to the ‘vascular area’. The segmented vertebral column is well +seen, as well as the vessels forming a network as they meander over the +vascular area. + +FIG. 47 exhibits the embryo more enlarged and in greater detail. + +FIG. 48 is an enlarged figure of the heart; the part D will ultimately +form the ventricle, B the auricle, and A the vena cava. At F the +aorta sends forth three branches which unite again. The nature of +these branches was not understood in Malpighi’s time. They have +been explained in modern times by embryologists working under the +inspiration of evolutionary theory as having once furnished the +blood-supply to the gills of a fish-like ancestor. + +FIG. 49 is a part of the segmented vertebral column still more enlarged. + +] + +[Illustration: + +FIG. 49A. ONE OF LEEUWENHOEK’S MICROSCOPES. To understand the figure +turn the book at right angles to the line of print. The object to be +examined--here the tail of a small eel--is placed in water in the +test-tube B. This test-tube is held firmly by two springs in the frame +A. The microscope itself is simply a flat metal plate D, into which is +let a very minute lens, the setting of which is shown above the letter +D (when the head of the eel is downwards). The lens is focused by means +of a fine screw which moves the whole plate. + +] + +The contributions of Malpighi to biological knowledge were very +numerous and important. The study of early development, embryology as +it is now called, was greatly extended by him. The later stages of +embryological development had been investigated by Fabricius (p. 110) +and some additions to the subject had been made by Harvey. Malpighi, +applying his microscope to the earlier germ of the animal body, +described in detail the development of the organs, notably of the +heart and the nervous system (Figs. 46-49). He also demonstrated the +minute structure of the skin, spleen and liver, in all of which there +are anatomical structures that still bear his name. He investigated +microscopically the structure and physiology of insects and plants, and +his figures of the cell-walls of the latter are good and clear. + +[Illustration: FIGS. 50-53 illustrate the blood corpuscles and +circulation after Leeuwenhoek. + +FIG. 50. Oval blood corpuscles of salmon showing nuclei. + +FIG. 51. Human red blood corpuscles. + +FIG. 52. Drawing of human red blood corpuscles for comparison with +Leeuwenhoek’s figures. + +FIG. 53. Capillary network in web of frog’s foot. A, C and E +are arterioles, B, D and F are venules. + +] + +A most remarkable contemporary microscopist was the Dutchman, Anthony +van Leeuwenhoek (1632-1723). Without medical or scientific training, +desultory and secretive in his mode of working, he was withal an +observer of genius and a very shrewd investigator. During his long +and industrious life he made a series of disconnected discoveries +which for originality and importance have been surpassed by no other +microscopic observer. He improved and extended the knowledge of the +capillary circulation of which Malpighi was the discoverer (Fig. 53), +he gave figures of the blood corpuscles (Figs. 50-1), of spermatozoa +and of fibres of muscles (Figs. 55-56a), and advanced the knowledge of +embryology. He always worked with a simple microscope, using lenses of +exceedingly short focal length (Fig. 49A). It is astounding that, with +such an instrument, he saw and figured bacteria as early as 1683 (Fig. +54). + +[Illustration: + +FIG. 54. THE FIRST REPRESENTATION OF BACTERIA. They were figured by +Leeuwenhoek in the _Philosophical Transactions of the Royal Society_ of +London in 1683. + +] + +[Illustration: FIGS. 55-56A. Drawings of the structure of muscle made +about 1682 by Leeuwenhoek. + +FIG. 55 shows a muscle teased up into bundles of fibres, magnified. + +FIG. 56 is a more magnified view of a bundle of fibres. The cut fibres +are shown at the end. + +FIG. 56A is a very highly magnified view of a single fibre showing very +clearly the striations that are very characteristic of voluntary muscle. + +] + +The short life of a second Dutch microscopist of the seventeenth +century, Jan Jacobz Swammerdam (1637-80), was abbreviated yet further, +as regards scientific achievement, by his insanity. In his brief +working period he produced his _Bible of Nature_ which, alone of +the scientific writings of his age, is still consulted by modern +naturalists for the unique beauty and accuracy of its figures. +He extended the knowledge of embryology and he made a series of +physiological experiments which involved the very modern physiological +device known as the ‘nerve-muscle preparation’. He is thus the founder +of an important department of Physiology. Swammerdam showed that, +during contraction, a muscle does not increase in bulk, and that +therefore the nerve brings nothing to it in the way of the hypothetical +‘nervous fluid’ in which many then believed (Fig. 63). He applied the +same reasoning to the heart (Figs. 57-60). Swammerdam was perhaps the +first to see the blood corpuscles. Like several of his contemporaries +and followers, he made injection preparations of much beauty and +delicacy. His great work was not published till after his death. The +copper plates that he had prepared for it were found and purchased by +Boerhaave (p. 140), who produced them at his own expense. + +These microscopists and several others in the seventeenth century +did much to explore the minute structure of the animal body. Their +revelations showed at once an unexpected complexity of all the parts, +and an unexpected resemblance of some of those parts which appear +diverse to the naked eye. Thus, the structure of the body came to be +subjected to a process that we may call ‘microscopic analysis’. For +long after the time of these classical microscopists no effective +improvements were made in the microscope, and the progress of +microscopic analysis lay almost dormant. With the improvements in the +microscope of the nineteenth century, the method was taken up again +with triumphant results. + +[Illustration: FIGS. 57-60. Experiments by Swammerdam to illustrate the +nature of muscular contraction. + +FIG. 57 is the simplest form of what physiologists call a ‘nerve-muscle +preparation’. It is merely a living muscle dissected away from the +body, but with its nerve still attached. In the experiment the two +tendons of the muscle are held by the two hands. An assistant pinches +the nerve with forceps. The muscle thereon contracts and draws the two +hands together. + +FIG. 58 shows the muscle passed through a glass tube. Its two tendons +are fastened by two pins. When the nerve is pinched the pins are drawn +towards each other, and the muscle, in contracting, fills the middle of +the tube. + +FIG. 59 shows the nerve-muscle preparation enclosed within a tube. +This tube has a narrow neck in which, at _e_, is a drop of water. The +other end of the tube is closed by a cork. The nerve may be squeezed by +pulling the thread _c c_, which passes through the cork and drags the +nerve into a narrow wire loop. + +FIG. 60 is a similar experiment with the heart, which contracts and +expands spontaneously and needs no irritation. + +The experiments 59 and 60 show that during ‘contraction’ no new +substance passes into the muscle, since it does not then increase in +size. This gives the death-blow to the conception of a ‘nervous fluid’ +passing into the muscle to cause contraction by distending it. + +] + + +§ 7. _From Alchemy to Chemistry._ + +During the sixteenth and the first part of the seventeenth century +the basic science of Mechanics had been placed on a firm footing +by Galileo. Astronomy, with Galileo and Kepler, had made the great +break with the past. Anatomy and Physiology had put on their modern +dress. Chemical knowledge, however, remained peculiarly backward. +Many advances, it is true, had been made in technical processes, +but investigations designed to throw light on theory were mostly +prosecuted by the band of dupes and charlatans who, since the Middle +Ages, had been seeking the Philosopher’s Stone. The old theory of the +four elements, earth, air, fire, and water (p. 34), formed an ill basis +for experiment. Some philosophers, it is true, had put forward crude +atomic theories, but they had little experimental evidence to adduce. +Nevertheless even the alchemists had made some advance and had, for +instance, perfected a system of weighing. + +The great defect of the ancient view of matter was that it contained +no definite conception of the nature of a _pure_ substance. Metals, +for instance, were regarded, like other substances, as a mixture +in certain proportions of the four elements of Aristotle (p. 34). +Thus, the transmutation of one metal or one substance into another +by distillation did not seem an absurdity, or even a task of special +theoretical difficulty. + +The main agent in changing the chemical outlook was Robert Boyle +(1627-91). He was a member of a small association of scientific men, +the _Invisible College_, which met first in London, then in Oxford, +and finally in 1663 was incorporated by Royal Charter as the _Royal +Society_. These men were satisfied that the only way to learn anything +effective about Nature was by observation and experiment. From their +discussions all purely speculative views were excluded. They agreed +to meet together solely to compare experiences, to demonstrate +experiments, and to draw immediate deductions. None of them was more +active in these matters than Boyle. + +The actual chemical and physical discoveries of Boyle were very +numerous, but his great achievement, the real service he rendered to +learning in general and to medicine in particular, was his introduction +of a new spirit into Chemistry. Under him that study was no longer +prosecuted for purely practical ends; it was set free from the mystic +factor in Alchemy and it was loosed from the chains which bound it +to Medicine, to the disadvantage of both. Chemistry thus became an +independent science, the principles of which were to be ascertained by +experiment, and its truths pursued for their own sake. + +Boyle demonstrated that the air is a material substance and has weight. +By means of his air-pump, he proved clearly that this substance is +necessary for the support of respiration (Fig. 63). The law of the +compressibility of gases is still known by his name. Most important of +all Boyle’s contributions to chemical theory was his adumbration of the +conception of a chemical element in our modern sense, and his view, +which he borrowed from another philosopher, of the atomic structure of +matter. + +Under the inspiration of Boyle and his colleagues, chemical works +of the second half of the seventeenth century exhibit in general a +positive, cautious, experimental spirit, and show a great contrast to +the mystical and obscure writings of the first half of the century, +which have much affinity with Alchemy. A fine exponent of this new +spirit was John Mayow (1645-79), who was prevented by an early death +from fulfilling all his promise. He was the first to recognize clearly +that there is a substance or principle in air which is concerned at +once with combustion, respiration, and the conversion of venous into +arterial blood. In this sense he was the discoverer of Oxygen (Figs. 74 +and 75). + +[Illustration: FIG. 61. ONE OF ROBERT BOYLE’S AIR-PUMPS. A cat has been +placed in the receiver. It shows signs of asphyxia as soon as the air +is exhausted by the pump.] + + +§ 8. _The Medical Theorists._ + +The great advances in the physical and biological sciences, instituted +during the sixteenth and seventeenth century, left the old medical +theories derelict. We have already traced the wrecking of the +Galenic physiology. With its destruction, the old ideas concerning +the three types of spirit, natural, vital, and animal, went by the +board. The doctrine of the circulation of the blood (p. 113) and the +investigations of the new Chemistry accorded ill with the old humoral +pathology, which ascribed all disease to excess or defect of one of +the four humors, blood, phlegm, bile, and melancholy (p. 34). Numerous +fresh theories arose, of which the more important can be classed under +the three headings _Iatrophysics_, _Iatrochemistry_, and _Vitalism_. + + +(_a_) _Iatrophysics._ + +The physical discoveries of Galileo and the demonstrations of +Sanctorius (p. 108) and of Harvey (p. 111) gave a great impetus to the +attempt to explain the workings of the animal body on purely mechanical +grounds. The writers who took this point of view are known as the +_Iatrophysicists_. One of the earliest and most impressive exponents of +physiological theory along these lines was the French philosopher René +Descartes (1596-1650). His work on the subject appeared posthumously in +1662. It is important as the first modern book entirely devoted to the +subject of Physiology. + +Descartes had not himself any extensive practical knowledge of the +subject with which he was dealing. On theoretical grounds he set +forth a very complicated apparatus which he believes to be a model +of animal structure. Subsequent investigation failed to confirm his +findings, and his work soon passed into oblivion. For a time, however, +it attracted much attention and many followers. A strong point in his +theory is the great stress laid upon the nervous system, and its power +of co-ordinating the different bodily activities. Thus stated, his view +may seem not far from the modern standpoint, though in fact he was +grotesquely wrong in detail. An important part of his theory is the +complete separation of Man from all the other animals. Man, according +to him, differs from all other animals by his possession of a soul, +which is situated in a structure in the brain known to physiologists +as the ‘pineal body’! Animals, he held, have no soul, and all their +actions and movements, even those which seem to express pain or fear, +are purely automatic. It is the modern theory of ‘behaviorism’ with +man excluded! (Figs. 62 and 63.) + +[Illustration: + +FIG. 62. DESCARTES’ conception of the relation of a sensory impression +and a motor impulse. The image of the object ABC passes to the eye and +is formed on the retina. Owing to the optical properties of the eye, it +is there inverted. The image is inverted yet again within the brain, +where it passes to the pineal gland H at the point _b_. The position +and character of the image formed on the retina determines the nature +and distribution of its effect on the pineal body. According to the +nature and distribution of that effect is the result on the nerve, +and through it, by the passage of nervous fluid, on the muscles. The +movement in the nerve is initiated at the point _c_. The relation +between _b_ and _c_ is an insoluble mystery in which is wrapped up the +very nature of the soul. (From the posthumous work of Descartes on +Physiology.) ] + +[Illustration: + +FIG. 63. DIAGRAM OF DESCARTES to illustrate his theory of nervous +action. P R and _q s_ are nerves which supply the muscles of the eye +T and V V. Descartes held that these nerves were hollow and provided +with valves, which can be seen at the point at which the P R and _q s_ +first branch. These valves were partly controlled by little fibrils +(which can be seen in the main stems of P R and _q s_ and in certain of +their branches). These valves control the movement of the fluid within +the hollow spaces of the nerves. Additional complication is lent to +the scheme by the fact that P R and _q s_ intercommunicate at certain +points. The view of Descartes, and all such theories of nervous fluid, +were destroyed by the experiment of Swammerdam (Figs. 57-60), which, +however, long remained unpublished. + +] + +More lasting was the achievement of Giovanni Alfonso Borelli +(1608-79), an eminent mathematician who was professor at several +Italian universities and the friend of Galileo and Malpighi. Stirred, +like Descartes, by the success of Galileo in giving a mathematical +expression to mechanical events, Borelli attempted to do the same with +the animal body. In this undertaking he was, in fact, very successful. +That department of Physiology which treats of muscular movement on +mechanical principles was effectively founded and largely developed by +him. Here his mathematical and physical training was specially useful. +He endeavored, with some success, to extend mechanical principles to +such movements as the flight of birds and the swimming of fish. When he +came to an analysis of some of the other activities of the body, such +as the action of the heart, or the movements of the intestines, he was +less successful, and he naturally failed altogether in his attempt to +introduce mechanical ideas in explanation of what we now know to be +chemical processes, such as digestion in the stomach. + +Undeterred by Borelli’s failure, other writers sought to find +mechanical explanations of physical processes. As is usual in such +cases, the amount of theory was inversely proportional to the amount +of knowledge. The views of some of the later ‘Iatrophysicists’ became +very fantastic. Belated representatives of the school are the writers +of the great French _Encyclopédie_ (1751-72), and notably its main +author, the man of letters, Denis Diderot (1713-84). + +[Illustration: + +FIG. 64. DIAGRAMS FROM BORELLI, showing one of his attempts to analyse +the movements of the muscles, in this case of the arm, according to the +principles of the science of Mechanics as expounded by Galileo. The +figure should be considered in conjunction with Fig. 65 opposite. + +] + + +(_b_) _Iatrochemistry._ + +Just as there were some who sought to explain all animal activity on +a mechanical basis so others resorted to chemical interpretation. +These may be termed _Iatrochemists_. The most prominent was Franciscus +Sylvius (1614-72), professor of Medicine at Leyden. That university +had become, in the second half of the seventeenth century, the most +progressive scientific center north of the Alps. It was the seat of the +first University laboratory, built at the instigation of Sylvius. + +Sylvius devoted much attention to the study of salts. He recognized +that they were the result of the union of acids and bases, and he +attained to the idea of chemical affinity--an important advance. He +looked at the phenomena of life also from the chemical point of view. +Well abreast of the anatomical knowledge of his day, and accepting +the broader lines of mechanistic advance in Biology, such as the +circulation of the blood and the mechanics of muscular motion, Sylvius +sought to interpret other activities in chemical terms. His position +and abilities as a teacher gave his views wide currency and he and his +pupils occupy a large part of the field of medical theory until well +into the eighteenth century. + +Under the influence of this school, almost all forms of vital activity +were expressed in terms of ‘acid and alkali’ and of ‘fermentation’. +The latter process was assumed to be of a chemical order, and no +clear distinction was made between changes that are brought about by +‘unorganized’ ferments, such as gastric juice or rennet, and changes +that are brought about by the action of micro-organisms, such as +alcoholic fermentation or leavening by yeast. Nevertheless, the school +of Sylvius and its immediate successors added considerably to our +knowledge of physiological processes, notably by their examination of +the body fluids, especially the digestive fluids such as the saliva, +and the secretions of the stomach and of the pancreas. + +[Illustration: + +FIG. 65. DIAGRAM OF MUSCULAR ACTION involved in lifting a weight in the +hand. It illustrates how muscular movement may sometimes be resolved +into terms of the lever. In practice, however, it is usually necessary +to involve a whole system of levers, pulleys, resistances, &c., as +Borelli clearly perceived. (Compare Fig. 64.) + +] + + +(_c_) _Vitalism._ + +Yet another school of medical theorists arose under the leadership of +the German chemist and physician, George Ernest Stahl (1660-1734). +Stahl is best remembered as the author of the famous theory of +_phlogiston_, a hypothetical substance with which bodies were supposed +to part during the process of burning (p. 151). He is important in the +history of science for his success in grouping chemical phenomena and +therefore in systematizing the study of the subject. For our purpose, +however, Stahl stands as the protagonist of that view of the nature of +the organism which now goes under the term _Vitalism_. Though expressed +by him in obscure and mystical language, it is, in effect, a return to +the Aristotelian position and a denial of the view of Descartes. To +Descartes the animal body was a machine. To Stahl the word _machine_ +expressed exactly what the animal body was not. The phenomena +characteristic of the living body are, he considered, not governed by +physical and chemical laws, but by laws of a wholly different kind. +These laws are the laws of the _sensitive soul_. The _sensitive soul_ +of Stahl is, in its ultimate analysis, not dissimilar to the _psyche_ +of Aristotle (p. 32). Stahl held that the immediate instruments, the +natural slaves of this sensitive soul, were chemical processes and his +Physiology develops along lines of which Aristotle could know nothing. +This does not, however, alter the fact of his hypothesis being an +essentially vitalistic one of Aristotelian origin. + + * * * * * + +The language and the theories of the Iatrophysicists, the +Iatrochemists, and the Vitalists of the seventeenth and eighteenth +centuries have long been discarded by men of science in the form in +which they were originally propounded. Nevertheless, they represent +three attitudes to the activities of living things which have present +and current meaning. Each seems to present some aspect of truth. +Whether some physiological thinker will combine all three aspects into +one coherent whole, it is for the future to decide. Yet it is certain +that all three lines of approach remain of value, and the stimulus +provided by each of the three inspires investigation at the present +day. In this sense we enter on the period of modern Medicine in the +seventeenth century. In this sense the foundations of modern rational +Medicine may be said to have been laid by Borelli, Sylvius and Stahl, +with Galileo, Boyle and Harvey standing behind them. + + + + +V + +THE PERIOD OF CONSOLIDATION + +(FROM ABOUT 1700 TO ABOUT 1825) + + +§ 1. _The Reign of Law._ + +During the sixteenth and seventeenth centuries the human mind cast +off its medieval vestments and, having refreshed itself at the spring +of Antiquity, turned to array itself in the garments of the New +Philosophy. The advent of new ideas and new knowledge had been very +rapid. The _method_ of Research had been determined by Galileo at the +beginning of the seventeenth century. The _meaning_ of Research was +determined by a second great investigator, Newton, at the end of the +same century. + +The change wrought in the thought of their time by Vesalius, Galileo, +Harvey and their like was quantitative rather than qualitative. They +discovered new laws of Nature, but the discovery of such new laws was +hardly unprecedented. Law had been traced in the heavens from of old. +The rules of planetary and stellar motion had been gradually developed +from the simple astronomical theories of the ancients. The great +astronomers of the sixteenth and seventeenth centuries did not hesitate +to appeal to the records and doctrines of medieval writers, for new +mathematical relationships of the heavenly bodies had been elicited +even during the Middle Ages. In the sixteenth century Astronomy under +Tycho (died 1601) put her house in order for the ‘Great Instauration’ +of the coming age. And then Galileo startled the world (1604) with that +new star of his (p. 104), among the most remote heavenly bodies in the +very region held by the Aristotelian and Platonic schemes to be utterly +changeless. The Revolution in Thought had begun, though no new order +had been established. + +By 1618 Kepler had enunciated his ‘three laws of planetary motion’, +bringing these movements into an intelligible relation with each other. +Then the experimental philosophers set forth to establish terrestrial +mechanics. They determined the mode of action of gravitation, and +Galileo came near to the ‘three laws of motion’ which we call Newton’s. +But it was Newton who first affirmed them clearly and succeeded in +linking them with Kepler’s laws of planetary motion. Before Newton, no +man had shown or perceived that rule by which the natural succession of +earthly phenomena is in relation to that of the heavenly bodies. Nay, +Faith and Reason alike would have been against such a view. To prove +that the relationship amounted to identity, to move men’s minds to see +that the force that causes the stone to fall is that which keeps the +planets in their path, this was Newton’s unique achievement. It was +Newton who first enunciated a law whose writ ran alike in the Heavens +and on the Earth. With Newton the Universe acquired an independent +rationality, and the whole cosmology of Aristotle, of Galen, and of the +Middle Ages lay in the dust. + +When Newton had completed his work, the Gravitation of the Earth and of +the Heavens was seen to be one, and all the Mechanism of the Universe +lay spread before him. The vision was set forth in his _Principia_ +(1687). It established a view of the structure and working of the +Universe which has survived to our own generation. + +And now as to the change wrought in men’s minds. It was something more +than a Revolution. It was the establishment of a New Order. Newton +conceived a working Universe wholly independent of the Spiritual Order. +As to how far his vision is philosophically tenable and as to how far +he realized its nature, these are matters which we need not discuss +here. There can, however, be no doubt that Newton utterly destroyed the +very foundations of medieval thought. With Newton there sets in the +last stage of ‘scientific determinism’. + +During the two centuries and a half since the _Principia_ appeared, +Science has developed prodigiously along the lines into which Newton +led her. In reliance on the universality of Natural Law, the stars in +their courses have been paced, weighed, measured, analysed. The same +process, directed to our own planet, has traced its history, determined +its composition, demonstrated its relation to other bodies. Physicist +and chemist have suggested a structure in terrestrial matter similar +to that of the stars and suns. The world has been reduced to a unitary +system. Wherever men have sought Law, they have found Law. With search +skilful enough and patient enough, Law has ever emerged. It has been +_the Age of the Reign of Law_. + +It is true that in our own time philosophers in general have come to +see that these Laws of Nature are within us as much as without; that +they are, in part at least, the result of the structure of our minds. +This is a point of view, however, which has not affected, and perhaps +will not affect, the working man of science. His constant occupation, +since the days of Newton, has been the pursuit of Law, and he has +always been satisfied that Law has only to be sought in order to be +found. This conception has affected the medical and biological sciences +very deeply. Thus the influence of the Newtonian philosophy is as +traceable in them as it is in the astronomical and physical sciences. +Galileo showed men of science that weighing and measuring are worth +while. Newton convinced a large proportion of them that weighing and +measuring are the _only_ investigations that are worth while. The +question as to whether this view is ultimately true or philosophically +justifiable does not need discussion at the moment. The point, for our +immediate purpose, is that the view has been and is very widely held. + + +§ 2. _The Rise of Clinical Teaching._ + +The eighteenth century dawned with the refreshing breeze of Newtonian +philosophy blowing through it. During the previous two hundred years +there had been an immense amount of new and fruitful research along +diverse lines. Chemistry and Mechanics, Botany and Comparative +Anatomy, Descriptive Anatomy and Experimental Physiology, Epidemiology +and Microscopic Analysis, all had yielded startling results. The +new generation was bewildered with the very mass and novelty of the +material. The Biologists of the time must have been well nigh hopeless +of reducing their vast accumulations to order, when they contemplated +the beauty and symmetry of the mathematical relations that Newton +and his followers had introduced into Cosmic conceptions. Thus the +eighteenth century is a period for Biology of pause and consolidation +during which attempts were made to introduce unitary conceptions +into the mass of accumulated material. It was, moreover, a period of +consolidation not only of ideas but also of teaching. These tasks +at first turned men’s minds away from the immediate accumulation of +further knowledge. So it is that the first half of the eighteenth +century exhibits something of a gap in the progress of Research. The +medical field is largely filled by two great figures, Boerhaave and +Haller. + +Until the seventeenth century there was no systematic clinical +teaching. The Universities gave medical degrees on the basis of a +spoken disputation. No contact with the patient was demanded. The +first effective attempt to change this was at Leyden, where about 1636 +clinical teaching was instituted. Owing to this, and to the fact that, +as at Padua, students of every religious denomination were accepted, +Leyden became much frequented by foreign and especially by Protestant +students. The attractions of the place were increased by Sylvius (pp. +131-2) who, in the second half of the seventeenth century, added +laboratory instruction to his clinical teaching. Leyden had several +eminent anatomists, while its botanic garden and museums added to the +practical character of the medical instruction that it offered. + +Hermann Boerhaave (1668-1738) was first appointed as a teacher at +Leyden in 1701. At once the medical school attained a front rank +reputation which rapidly came to surpass even that of Padua. Boerhaave +had very few beds at his disposal, but never did man make better +use of his opportunities. Besides clinical, chemical, botanical +and anatomical instruction he followed such of his patients as died +into the post-mortem room and there demonstrated to his students the +relation of lesions to symptoms. He is thus the introducer of the +method of medical instruction still in vogue in our modern medical +schools. + +Boerhaave was a man of wide culture. He rescued and published the +plates of the priceless _Bible of Nature_ of Swammerdam (p. 121). He +brought to Leyden the best anatomist of his age, Bernard Siegfried +Albinus (1697-1770). With him Boerhaave edited in superb form the +collected works of Vesalius (1725, p. 85 ff.). The edition exhibits +remarkable prevision of the scientific needs of the scholarship of +our own time. To Albinus, and indirectly to Boerhaave, we owe the +most beautiful of all works on muscular anatomy (1747), a book still +in current use (Fig. 66). Apart from his clinical ability and acumen +Boerhaave was a skilled chemist, botanist, and anatomist. + +With all these accomplishments Boerhaave was better able than any man +of his time to achieve something like a medical synthesis, to bring +all the sciences to the service of the patient. Taking one thing +with another, considering his influence as a teacher, his clinical +acumen, his power of inspiring younger workers, his wide learning, +his balanced vision, his eagerness for new knowledge, his sanity, his +humanity, his generosity, and his prophetic power, Boerhaave must +be regarded as the greatest physician of modern times. To him the +debt of British Medicine, and through it of British well-being, is +quite incalculable. Through his pupils he is the real founder of the +Edinburgh Medical School, and through it of the best medical teaching +in the English-speaking countries of the world. The success of the +Edinburgh school, founded while the great Leyden professor was still in +his prime, can be ascribed to two causes which are perhaps reducible to +one--the inspiration of Boerhaave. These two causes are, firstly, the +enthusiasm of its early teachers, and, secondly, the concentration of +all the medical teaching, both clinical and subsidiary, in one great +university school. + +[Illustration: FIG. 66. TWO PLATES FROM BERNARD SIEGFRIED ALBINUS. +_Anatomical Plates of the Muscles of Man_, Leyden, 1747. These are the +most beautiful and among the most accurate anatomical figures ever +published.] + + +§ 3. _Physiology passes to the Modern Stage._ + +The only figure in the eighteenth century whose influence is comparable +to that of Boerhaave is his pupil, the Swiss Albrecht von Haller +(1708-77), one of the most accomplished men of all time. In actual +scientific achievement Haller stands, indeed, far above his master. +He achieved distinction as poet, botanist, anatomist, and novelist, +carried on a prodigious correspondence, was an exceedingly learned +bibliographer, and perhaps the most voluminous of all scientific +authors. His special distinction, however, is as a physiologist. + +Haller’s great work, _Elements of the Physiology of the Human Body_ +(1759-66), marks the modernization of the subject of which it treats. +Of the highest importance were his researches on the Mechanics of +Respiration, on the formation of bone, and on the development of the +embryo. He did good work on the action of the digestive juices. His +most important contributions, however, are his conceptions of the +nature of living substance and of the action of the nervous system. +These conceptions formed the main background of biological thinking +for a hundred years, and are still integral parts of physiological +doctrine. + +All departments of Medicine must be influenced by the views we may hold +on the nature and action of the nervous system, just as all parts of +the body are influenced and indeed are linked together by that system. +Thus the growth in knowledge of the physiology of the nervous system is +extremely important to us if we would gain a true idea of the progress +of Rational Medicine. + +When we look into the history of nervous Physiology before Haller, we +shall be struck by the smallness of the observational foundation of a +vast speculative structure. That we may be the more charitable in our +judgment of such fanciful developments, we may recall that the Mind is +so constructed that it can take little interest in the accumulation of +instances unless it can adduce general laws therefrom. Theory is thus +as necessary to practice as practice to theory. The earlier doctrines +of the nature of nervous action are, however, so unlike those we +now hold that we can afford to pass over them lightly. They consist +of speculations on the topic of the seat of the soul, together with +explanations which suppose the passage either of a fluid or of some +chemical change down the nerves. Haller was the first to construct a +theory of the nervous system that has an appearance of modernity. + +During the seventeenth century the favorite doctrine of nervous action +supposed the existence of a nervous fluid. This, it was held, passed +down the nerves to inflate or extend the muscle fibers. Inflation was +supposed to shorten the fibers and so the muscle came to contract. An +exquisite experiment by Swammerdam with his nerve-muscle preparation +had disproved this (p. 123). But Swammerdam’s work was unknown till +published by Boerhaave in 1736, and so the matter stood till Haller’s +time. + +Haller concentrated the problem on an investigation of the fibers. +A muscle fiber, he pointed out, had in itself a tendency to shorten +with any stimulus, and afterward to expand again to its normal length. +This capacity for contraction Haller, following a predecessor, called +_irritability_. He recognized the existence of ‘irritability’ as an +element in the movement of the viscera, and notably of the heart, and +of the intestines. The feature of ‘irritability’ is that a very slight +stimulus produces a movement altogether out of proportion to itself, +and that it would continue to do this repeatedly so long as the fiber +remained alive. + +But besides the force inherent in a muscle fiber Haller showed that +there was another force which comes to it from without, is carried +from the central nervous system by the nerves, and is the power by +which muscles are normally called into action. This force, like that +of irritability, is independent of the will, and like it can be called +into action after the death of the animal. Haller thus distinguished +the _inherent muscular force_ from the _nerve force_. Both these forces +he further distinguished from the natural tendency to contraction and +expansion, under changing conditions of humidity, pressure and so on, +of all tissues, living or dead. + +Haller, having dealt with the question of movement, turned to that +of feeling. He was able to show that the tissues are not themselves +capable of sensation, but that the nerves are the sole channels or +instruments of this process. He showed how all the nerves are gathered +together into the brain, and he believed that they tended to its +central part. These views he supported by experiments and observations +involving injuries or stimulation to the nerves and different parts +of the brain. He ascribed special importance to the cortex, but the +central parts of the brain he regarded as the essential seat of the +living principle, the Soul. + +Throughout his discussion Haller never falters in his display of the +rational spirit. He develops no mystical or obscure themes, and, +although his view of the nature of Soul may lack clarity, he separates +such conceptions sharply from those which he is able to deduce from +actual experience. He is essentially a modern physiological thinker, +and certain of his themes were developed by workers who come on the +frontiers of what we have called the ‘period of consolidation’. + +Among these workers we would select the Scottish surgeon Sir Charles +Bell (1774-1842), who in 1811 showed that of the two roots from the +spinal cord by which all the nerves of the body arise one root conveys +only sensory elements while the other conveys only motor elements (Fig. +98, p. 208). By this discovery Bell not only completed the views of +Haller on the central nervous system, but also brought them within the +range of practical Medicine. + + +§ 4. _Some Physiological Advances._ + +Haller provided a philosophical basis to physiological conceptions. +There were, however, other workers of the time who added to the +knowledge of actual workings of the animal body. First among these, +both in time and eminence, stands the English country clergyman +Stephen Hales. + +The Rev. Stephen Hales (1677-1761) was by temper a biologist, but he +had received a training in Mathematics and Physics. With this ideal +equipment, he proceeded to investigate the Dynamics of the Circulation. +His method consisted in applying the principle of the pressure gauge +or manometer to living things. By tying tubes into the arteries and +veins of animals, he was able to record and measure the blood-pressure. +He thus laid the foundation of an important mode of studying the +diagnosing disease. He extended his exact investigations into most of +the mechanical aspects of the circulation. He computed the circulation +rate and he estimated the actual velocity of the blood in veins, +arteries, and capillary vessels. He made a very important contribution +by showing that the capillary vessels are liable to constriction and +dilatation, a knowledge that has since become not only important for +physiological theory but of primary significance to the practising +physician (p. 309). He began to explore the wonderful mechanism of +the heart by which that organ adjusts itself to its needs of output. +He exhibited his versatility by important contributions to many other +departments, as, for instance, his discoveries on Respiration, his +improvements in Ventilation (Fig. 67), and his campaign for Temperance. +All his work is characterized by simplicity and directness, the supreme +marks of his genius. + +[Illustration: + +FIG. 67. WINDMILL VENTILATOR designed by the Rev. Stephen Hales, and +erected by order of the Aldermen of the City of London, in 1752, on the +roof of Dick Whittington’s Gate at Newgate Prison. From a print in the +British Museum. + +] + +In the meantime considerable progress was made in the knowledge of the +digestive processes. The French naturalist, René Antoine de Réaumur +(1683-1757), best remembered for his thermometer (1731) and for his +superb work on insects (1734-42), made a series of experiments on +gastric digestion in birds (1752). By an ingenious contrivance he +succeeded in obtaining gastric juice in a pure state. He was able to +demonstrate its power to dissolve food substances in a test-tube kept +at body temperature. This was important, since many believed that +the process of solution was the result of a churning process induced +mechanically by the muscles of the stomach-wall. Réaumur thus gave the +death-blow to the Iatrophysical conception of digestion (p. 130). + +The investigation of gastric digestion was further pursued by a +versatile Italian, the Abbé Lazaro Spallanzani (1729-99), who showed +that the churning action is an aid, but not an essential, to the +process of digestion (1782). He proved that digestion was not of the +nature of putrefaction and differed essentially from the fermentation +of wine. Spallanzani thus improved on the view of Sylvius (p. 132), +and took a step towards that solution of the natures of putrefaction, +fermentation, and digestion which was finally provided by Pasteur (p. +225). He showed that the gastric juice was secreted by the stomach +itself, and not introduced into it from other organs. A suspicion +that the gastric juice contained a free acid crossed his mind. He +observed that it curdled milk and so began our knowledge of a separate +ferment, that of ‘rennet’. Spallanzani’s results may be summarized +by saying that he showed that gastric juice had a solvent power _sui +generis_, and that this power or faculty was of a different order from +putrefaction or vinous fermentation. + +The phase of digestive physiology represented by Réaumur and +Spallanzani was brought to a close by the English physician William +Prout (1785-1850), who demonstrated in 1823 the existence of free +Hydrochloric Acid in the stomach. He showed that the presence of this +acid was necessary for gastric digestion, but that the actual process +of solution of food was the work of another agent. The matter was at +last brought into the range of medical practice by an American Army +Surgeon, William Beaumont (1785-1853), who, in the ten years ending +1833, had the opportunity to investigate gastric juice in a man who, +having been shot in the stomach, had a permanent fistula. Through this +the juice could be obtained and the lining membrane of the stomach +examined at will. + +[Illustration: + +Experiments illustrating the effects of metallic contacts on the nerves +and muscles of frogs’ legs. From A. Galvani, _On Electric Forces_, 1792. + +FIG. 68. Contact is established between water in two dishes. In one +lies the end of the nerve with the spinal cord and vertebral column +attached. In the other are the feet of the frog. + +FIG. 69 shows contact by a metal bar with two damp mats on one of which +lies the spinal cord and on the other are the feet. + +FIG. 70 shows a broken contact which can be completed by bringing the +metal rods together. + +] + +An important department of Physiology was opened by the extension +of the knowledge of electric phenomena to the living body. Static +electricity had been studied since the beginning of the seventeenth +century. Luigi Galvani (1737-98) of Bologna, while investigating the +susceptibility of nerves to irritation, showed that nervous action +could be induced by electrical phenomena (1791). He was, as a matter of +fact, producing an electrical current. Many thought at the time that a +new kind of ‘animal electricity’ had been produced and they dubbed it +‘galvanism’. + +Alessandro Volta (1745-1827) of Pavia, deviser of the ‘Voltaic pile’ +(Figs. 71-3), had long been working at electricity. He was able to +demonstrate (1800) that galvanism is without any essential animal +relationship, and showed that a muscle can be thrown into continuous +contraction by repeating electric stimulations. + +Humbug and misunderstanding in connection with the electrical relations +of living tissues were rife, and it was not till after the period we +are now considering that electricity came to take a place in rational +Medicine. The change came with E. Du Bois-Reymond (1818-96), who took +the matter up scientifically about the middle of the nineteenth century +(1843 onwards). He showed that a nervous impulse is accompanied by the +passage along the nerve of a change of electrical potential. It should +be added that, despite all the work since done upon the nervous system, +this is still the only physical accompaniment of a nerve impulse that +has been detected. + +[Illustration: FIGS. 71, 72, and 73. From an article by Volta, _On the +Electricity excited by the mere Contact of Substances of different +kinds_, published in 1800. + +FIG. 71 is the famous ‘Couronne de tasses’. It consists of a series of +vessels containing salt water, in which are steeped plates of alternate +silver A and zinc Z. The plates are connected by strips of metal _a_ +_a_ _a_. If the first and the last cup be connected by a conductor, a +current flows from one to the other. + +FIG. 72 is a simple voltaic pile, consisting of alternate disks of +silver and zinc, sandwiched between wet strips of leather. The pile +is held by glass rods _m_ _m_ _m_. From the lowermost disk a strip of +metal passes to a vessel containing salt water. A current will pass +from the uppermost disk to the vessel if the two are connected by a +conductor. + +FIG. 73 is a similar apparatus with two piles connected by a metal +plate _c c_, and two vessels _b_ _b_. A current will pass between the +two vessels _b_ _b_ if they are joined by a conductor. + +] + + +§ 5. _Discovery of the Nature of the Air._ + +The seventeenth century saw advances in the knowledge of the air. +Boyle (1654, p. 124) had shown by means of his air-pump that air was +a material substance and could be weighed. By exhausting the air from +a vessel in which an animal had been placed, he showed that it was +this material substance and no ether, spirit, or other mysterious +entity which supported respiration. Mayow (1668, p. 126) proved that +a part only of the air was necessary for life, and later that this +same part was removed equally by respiration and combustion (Figs. +74-5). His work was forgotten for a hundred years. The great theorists, +Stahl, Boerhaave and Haller, knew him not, and Stahl’s doctrine of +_phlogiston_ set back the hands of the clock. No advance was made till +the work of Joseph Black (1728-99) which appeared soon after the middle +of the eighteenth century. + +[Illustration: FIGS. 74 and 75, illustrating the chemistry of burning +and breathing, from a work issued by Mayow in 1674. The experiments +show the essential similarity of the two processes in their effect upon +the air. + +FIG. 74. A candle is burning and a piece of inflammable material is +being ignited in a glass vial by a burning-glass, the mouth of which is +under the surface of the water. The air can, if desired, be changed or +sampled through the attached tube. + +FIG. 75. A mouse confined under a glass cover. The air under this cover +communicates with that in the vessel below, and can be cut off more or +less completely by means of a more or less porous diaphragm. + +] + +Black was a cautious investigator and his success was due to the +accuracy of his measurements. He was aware of the fact that chalk, when +heated, is transformed into quicklime (equation 1, p. 152), thereby +losing its power of effervescing with acids, but gaining the power of +absorbing water (equation 2). In modern nomenclature, the changes are: + + (1) CaCO_{3} = CaO + CO + (2) CaO + HO = Ca(OH)_{2} + +The first achievement of Black was to show that in the process of +heating the chalk lost weight (equation 1). This was a blow at the +phlogiston theory, for it had been supposed that quicklime consisted +of chalk _plus_ phlogiston, and that the phlogiston was conveyed to it +during the heating. Black now showed that if slaked lime be treated +with a mild alkali, such as the carbonate of sodium, it is changed back +to the state in which it was before heating, in fact into chalk, while +the mild alkali is converted into a caustic alkali. As we now express +it: + + (3) Ca(OH)_{2} + Na_{2}CO_{3} = CaCO_{3} + 2NaOH + +Black’s triumph consisted essentially in showing that reactions (1) and +(3) were indefinitely reversible and that the same amount of CaCO_{3} +could always be extracted from (3) as was put into (1). Moreover, he +showed that a definite amount of chalk, whether heated into quicklime +or not, neutralized an equal weight of acid, the only difference being +that the neutralization took place with effervescence and loss of +weight if the chalk were unheated, and without effervescence or loss of +weight if the chalk were first heated into quicklime. Thus: + + (4) _Unheated_ CaCO_{3} + 2HCl = CaCl_{2} + H_{2}O + CO_{2} + (5) _Heated_ CaO + 2HCl = CaCl_{2} + H_{2}O + +The substance given off by the chalk in (1), absorbed by it in (3), +and produced by the reaction (4), he named _fixed air_. We now call it +_Carbon dioxide_. The conversion of caustic lime into ordinary chalk +by exposure, CaO + CO_{2} = CaCO_{3}, proves that Carbon dioxide is a +normal constituent of the atmosphere. Black learned something of its +properties, and his work is also of very great importance as the first +detailed quantitative study of a chemical reaction and its reversal. +The properties of Carbon dioxide were further investigated (1766) by +Henry Cavendish (1731-1810). + +The next advance in the chemistry of the air was made by the English +Unitarian Divine, Joseph Priestley (1733-1804). A series of important +observations was made by him in the seventies and eighties of the +eighteenth century. He showed that green growing plants would make +respired air again respirable, and that they gave off a respirable +gas. In 1774 he prepared Oxygen by heating certain oxides, though, +still hampered by the phlogiston theory, he failed to recognize the +nature of the oxygen he had produced. The conclusions of his striking +experiments on blood, which he showed to depend on this same agent for +its changes from venous to arterial, were similarly vitiated. + +[Illustration: + +FIG. 76. APPARATUS from Joseph Priestley’s _Experiments and +Observations on different Kinds of Air_, Birmingham, 1774. In the +background can be seen an experiment on the effect of combustion on +confined air. There are also two cylinders inverted over water in which +green plants are growing. In one of them the growing plant has given +off a gas (oxygen) which Priestley showed could support both combustion +and respiration. In the foreground under a bell-jar are some mice on +which Priestley performed respiratory experiments. + +] + +The real passage to the modern point of view in our knowledge of the +air was made by the brilliant French chemist Antoine Laurent Lavoisier +(1743-94). He made an extensive quantitative investigation of the +changes during breathing (Fig. 77), burning, and calcination. In the +course of these he discovered the true composition of respired air, and +showed how both Carbon dioxide and water are normal products of the act +of breathing. If clear grasp of the implication of discovery be made +the test, Lavoisier must be regarded as the discoverer of Oxygen. + +Cavendish (1731-1810) had already discovered the composition of +water (1785). Lavoisier concluded that water and Carbon dioxide are +produced by the process of oxidation in the lungs, and that it is +this oxidization process, and not any innate quality of a mysterious +character in the body or in the blood, that is responsible for the +bodily heat. Lavoisier introduced much of the chemical nomenclature +that we still employ. So far as respiration is concerned, subsequent +research has added much to his standpoint. In the purely chemical +aspect, however, it has altered little, though we now know that the +tissues and not the lungs are the seat of oxidation. + +[Illustration: + +FIG. 77. LAVOISIER in his laboratory making experiments on breathing. +To the right Madame Lavoisier sits at a table, taking notes. Lavoisier +stands behind, directing. To the left is the subject of the experiment. +His face is covered with a mask provided with a valve. He is breathing +into the apparatus. An assistant feels his pulse while a second +assistant collects the respired air in a bell-jar inverted over a +trough. + +From a contemporary sketch. + +] + + +§ 6. _Morbid Anatomy becomes a Science._ + +The main intellectual movement of the seventeenth and eighteenth +centuries had been focused, so far as Medicine was concerned, on the +manner of working of the animal body, the department that we now term +Physiology. It was necessary to obtain clear concepts of the action of +the body in health before venturing into discussion of its action in +disease. Towards the end of the seventeenth century, an industrious +compiler had put together all the then published records of post-mortem +examinations up to his time. During the first part of the eighteenth +century many practitioners in Physic and in Surgery published +isolated cases or groups of cases connected with particular diseases. +Boerhaave regularly attended post-mortem examinations (p. 140). No +general pathological principles had, however, yet been elicited on a +scientific basis. The theories of disease such as those of Boerhaave +were perforce still mainly speculative, for there were no extensive +records of the correlation of symptoms during life with the appearances +of the organs of the body after death, the subject we now call ‘Morbid +Anatomy’. This gap was first effectively bridged by Morgagni. + +Giovanni Battista Morgagni (1682-1771) was professor at Padua for no +less than fifty-six years. During this time he performed an enormous +number of post-mortem examinations, and made important contributions +to Descriptive Anatomy. In his seventy-ninth year, eleven years before +his death, there emerged from his enormous experience his work _On +the sites and causes of disease_. This classical treatise may still +be read with profit. Its leading feature is the very careful way in +which actual cases are recorded. The life-history of the patient, the +history of his disease, the events in connection with his final illness +and death, are all recounted with detail and care. The condition of +the organs at the post-mortem examination is minutely described and +an attempt is made to explain how the symptoms were the result of the +lesions. Morgagni is justly said to have introduced the ‘anatomical +concept’ into the practice of medicine. This concept is one of the main +elements in modern diagnosis, and a modern physician, in reflecting +on a case, considers first whether he is able to express the symptoms +in terms of lesion. There are many lesions of great importance and +frequent occurrence which Morgagni was the first to describe. + +The task which Morgagni had undertaken was worthily continued by the +Scot, Matthew Baillie (1761-1823), nephew, pupil, and heir of William +Hunter (p. 165). Baillie was a successful London practitioner. He +followed a new and convenient method in arranging his work according to +organs instead of by symptoms, as Morgagni had done. Baillie performed +post-mortem examinations on several men of eminence, among them Dr. +Johnson, whose lung he describes (see Fig. 78). + +The task of naked-eye pathological anatomy, effectively begun by +Morgagni, was effectively completed by Karl Rokitansky of Vienna +(1804-78). His work (1842-6) was based on an experience extending +over 30,000 post-mortems! Though disfigured by a bizarre theory, +it left but few gaps for subsequent workers. From now on, the +science of Pathology was to be prosecuted in a new spirit and with +new instruments. Even in his own day Rokitansky was something of an +anachronism, with his pure naked-eye anatomy hardly ever involving +experimental evidence on the one hand or the findings of the microscope +on the other. + +[Illustration: + +FIG. 78. PART OF THE LUNG OF DR. SAMUEL JOHNSON, from a drawing +published by Matthew Baillie. Johnson was a fat, unwieldy man, with +a great barrel chest, who suffered for many years from shortness of +breath. These are common associations with the pathological condition +known as _Emphysema_, in which the lungs, which are normally of fine +spongy texture, become full of abnormally large cavities, so that, as +Baillie remarks, they come ‘to resemble the air cells of the lungs of +amphibious animals’ (cf. Fig. 45, p. 116). In the figure B represents +the external part of the lung and A its cut surface. On the cut surface +the large cellular structure can be seen. The very dark points are the +orifices of cut branches of the pulmonary vessels. + +] + + +§ 7. _Clinical Methods and Instruments._ + +The great teachers of the earlier eighteenth century, though better +equipped as regards knowledge than their predecessors, had hardly any +better means of diagnosis. Pulse-measurers and thermometers such as +those of Sanctorius and Galileo (p. 109) had proved impracticable by +the bedside. The microscope had not yet entered into Clinical Medicine. +Chemical analysis as applied to disease had proved, as yet, of little +value. + +The first efficient instrument of precision to merit clinical +adoption was the ‘pulse watch’, by Sir John Floyer (1649-1734), an +English provincial physician. It was introduced as early as 1707 as a +‘Physician’s Pulse Watch’ and was an instrument constructed to go for +just one minute. At that time the making of a twenty-four hours watch +with a seconds-hand presented great mechanical difficulties. Floyer’s +invention was not widely adopted at the time. Attempts were also made +to introduce a thermometer into practice, but again the construction of +suitable instruments proved impossible. + +Effective pulse watches and clinical thermometers did not penetrate +into the general practice of Medicine till well into the nineteenth +century. Two instrumental advances of first-class importance to +Medicine were, however, introduced during the later eighteenth century. +These were the methods of Percussion and Stethoscopy. + +Percussion of the surface of the body yields notes of varying degrees +of resonance. Its application has proved of great value to the +physician in outlining the position of the organs and of lesions, +especially those of the chest. It was invented by Leopold Auenbrugger +(1722-1809), a Viennese physician who first introduced it in 1761. Like +the thermometer, it was very slow in entering the general practice of +Medicine. + +Auenbrugger deserves great credit for his invention, but he did not +work out its application with anything like the completeness that +the Breton physician, René Théophile Hyacinthe Laënnec (1781-1826), +applied to his ‘stethoscope’ (1819). Laënnec’s instrument was of the +uni-tubular type that is now seldom seen. At first, indeed, he used a +mere roll of paper. His idea was rapidly diffused into every country. + +But Laënnec did far more than introduce a useful and convenient device +into Medicine. He explored with extraordinary skill the physical signs +in the chest which correspond to a large number of diseases. The major +part of our chest-lore and much of the technique and nomenclature of +chest examination come direct from him. Despite continual bad health +and the shortness of his life, Laënnec’s brilliance and devotion to +duty at a hospital in Paris enabled him to transmit his views and +methods to many other physicians, both French and foreign. He is +unquestionably among the greatest physicians of all time. Clinical +medicine assumes with him a completely modern aspect. In reading his +work one feels that, had he been called in consultation by a medical +man of our own day, the two would have been able to understand each +other perfectly, after only a little adjustment and explanation. + +[Illustration: FIGS. 79-82. LAËNNEC’S WOODEN STETHOSCOPE, from his work +of 1819, _On Instrumental Auscultation_. + +FIG. 79 is the complete instrument. + +FIG. 80 is the instrument in section. + +FIG. 81 is the ear-piece unscrewed. + +FIG. 82 is the detachable chest-piece terminating in a thin metal tube. + +] + + +§ 8. _Surgery and Obstetrics._ + +During the eighteenth century the improved knowledge of Normal and +Pathological Anatomy was a great aid to the surgeon. The technique of +Surgery was certainly improved. Operations were now being performed +with success that could not before have been attempted. Nevertheless +few important new principles were introduced until long after the +nineteenth century had dawned. It is indeed probable that as a means +of life-saving Surgery had an almost inappreciable effect on vital +statistics until the advent of Anaesthesia and Antiseptics. Even the +greatest surgeon of the eighteenth century, John Hunter, introduced no +fundamental new surgical principles. True, the names of many surgeons +of the period have become associated with operations invented or +introduced by them, but it was not till after the advent of antiseptic +methods that these were practised with full success. There are but two +surgical matters in which advances of great significance can be said to +have been made. These were the treatment of Venereal Disease and the +treatment of Labor. + +Syphilis, which existed in Europe in the later Middle Ages, had +usually been confused with Leprosy and other conditions (p. 98). Its +treatment by Mercury had been practised at least as early as the +fifteenth century, perhaps as an inheritance from the Arabic-speaking +physicians. During the sixteenth and seventeenth centuries various +other remedies were tried (Fig. 33); much quackery arose around them. +In the eighteenth century the accumulated experience of generations +returned again to Mercury. Satisfactory methods of administration were +evolved and the treatment became standardized. It hardly changed until +the twentieth century. + +[Illustration: + +FIG. 83. LYING-IN SCENE in the sixteenth century from a contemporary +work on midwifery. Drinking and feasting is going on in the room where, +in addition to the patient, there are two men, five women, and two +children. A dog chews a bone on the floor, cooking is in progress in +the adjoining room. Food and drink is being forced on the unfortunate +patient herself. The whole scene, which is intended to portray an +upper-class household, suggests carousal, disorder, and dirt, as well +as ignorance of the most elementary principles of hygiene. + +] + +The treatment and care of women in Labor made considerable progress +during the period of which we are treating. We have seen how there were +advances even during the sixteenth century (p. 93) by such a writer as +Paré. Works on obstetrics intended for women were often printed in the +sixteenth century in France, England and Germany. Scientific obstetric + +works were produced especially in France in the second half of +the seventeenth century. The obstetric forceps was known, but was +still a family secret. At the time and for long after, there was a +great objection on the part of pregnant women to treatment by men. +The midwives were for the most part ignorant, dirty, unskilful and +superstitious, and the loss of life and health that resulted from +their mishandling was enormous. The objection to the ‘man midwife’ was +only gradually overcome, though his advent was unquestionably attended +by a fall in the mortality. About the middle of the eighteenth century, +moreover, the obstetric forceps came into wider use. One of the ablest +and most successful of the obstetric physicians was William Hunter +(1718-83), the brother of John Hunter. + +[Illustration: Early obstetric instruments. + +FIG. 84 is the very dangerous and brutal _Speculum matricis_ used to +force open the mouth of the womb in cases of difficult labor. A similar +instrument has been used since antiquity to dilate wounds. + +FIG. 85 is an even more terrible and powerful instrument, the +_Apertorium_, provided with a sharp edge by means of which the mouth of +the womb was violently cut or torn. + +In the seventeenth century less heroic measures began to be used, and +the obstetric forceps was introduced. + +FIG. 86 shows a pair of obstetric forceps as used in the seventeenth +century. The instrument is the direct ancestor of that now in use, +which, however, is a vast improvement upon it. The obstetric forceps +was invented by a member of an hereditary family of man midwives, at +the beginning of the seventeenth century. The nature of the instrument +was long kept a secret. This particular instrument was found by +accident in 1813, having been hidden under the floor by a member of the +family of the inventor. + +] + +Despite the absence of any great new principle in the surgery of the +period, there can be no doubt that a new spirit was introduced by +John Hunter (1728-93). His complex and interesting character demands +better treatment than it has yet received. As an investigator his +powers were superb, but, like Leonardo, he was handicapped at every +turn by literary incoherence. Nevertheless, with him Surgery begins +to appear, at last, as a real Science and not as a mere applied Art. +Hunter brought to bear on the subject a mind stored with ideas drawn +from Comparative Anatomy and Pathology. Quick to detect analogy, shrewd +in his scientific judgments, tireless and unsparing of himself in his +pursuit of truth, a victim of disease self-inflicted in the service of +science to which he was tragically a martyr in his death, he shows as +a heroic figure, rendered no less heroic by some very human failings. +Fully to appreciate so incoherent a writer, it is unfortunately +necessary to wade through many works written in his own clumsy and +ill-arranged manner. To gain any real idea of this great personality we +must consult the writings of his contemporary colleagues. + +So far as actual advances are concerned, two may be connected with +Hunter’s name. Firstly, in the treatment of the deadly condition known +as ‘Aneurysm’ he introduced a method of operation which is still in +vogue. Secondly, he enormously improved the method of making and +ordering a museum. His monument is the Hunterian Museum in London, +based on his specimens of which many may still be seen there. The +museums of Natural History, as now constituted in all civilized +countries, have been influenced by, if they have not been derived from, +that which he literally gave his life’s blood to found. He was right +when he said musingly in his illness, ‘You will not easily find another +John Hunter.’ + +[Illustration: + +FIG. 87. JOHN HUNTER’S COUNTRY HOUSE at Earl’s Court, Kensington, +before its demolition in 1886. This house was in the country in +Hunter’s day, though its site is now a busy part of London. For many +years he used it as a laboratory and menagerie, and much of his best +work was done there. + +] + + +§ 9. _The Beginnings of the Science of Vital Statistics._ + +Attempts to combat widespread disease and to improve the public +health are to be found in the history of all civilizations, both +ancient and modern. Nevertheless, the rational method cannot come into +operation until it has exact data upon which to work. Such data may +be numerically expressed, a fact first appreciated by the versatile +English physician and inventor, Sir William Petty (1623-87), who is +usually regarded as the father of the science of Political Economy. In +1662, and on many subsequent occasions, he joined a friend in issuing +_Natural and Political Observations upon the Bills of Mortality_ of +London. In this work he endeavored to deduce population, death-rates, +disease prevalence, and other matters of vital statistics from the +crude figures of the day. He was fully aware of the imperfection of his +materials, and on this account he urged the necessity of providing a +system and a government department for the collection of trustworthy +statistics. In his _Political Arithmetick_ (1683), the basic work of +modern Economics, he displays ideas of a very modern character. Among +these is his view that the true wealth of a country is to be sought in +its efficient man power. + +A number of Petty’s fellow members of the Royal Society began to take +interest in statistics. Chief among these was Edmund Halley, the +astronomer (1656-1742). Toward the end of the century (1693) Halley +produced a mass of statistics on the chances of life at various ages, +designed for the estimation of the price of annuities. During the +eighteenth century numerous writers devoted themselves to similar +investigations. An important contributor to the mathematical basis +of vital statistics was the French Huguenot and friend of Newton, +Abraham de Moivre (1667-1754). His _Doctrine of Chances_ (1715) and +his _Annuities upon Lives_ (1725) are important contributions to the +subject. His celebrated hypothesis that among a body of persons over +a certain age the successive annual decrease by death may be esteemed +as nearly equal (that ‘the decrements of life are in arithmetical +progression’) was under discussion for a century, but is now accepted. + +In 1761 a Prussian clergyman, J. P. Süssmilch (1707-82), produced an +extraordinary theological work, _The Divine Ordinance manifested in the +Human Race through Birth, Death, and Propagation_. Its object was to +exhibit God’s design in the constancy of the numerical relationships +of vital statistics. Despite the motive--somewhat unpromising for a +scientific treatise--the work is of great historic and scientific +importance, for it was based upon a vast mass of statistics and showed +a great advance in method. It stressed the importance of accurate data +and the necessity for numerous observations, if reliable conclusions +were to be drawn. From the time of the publication of the work of +Süssmilch, the statistical study of population advanced rapidly. The +basis of statistics was greatly improved by the introduction of the +census system which was put into action in England in 1801. + +The science of vital statistics was placed on a firm foundation by the +Belgian astronomer Lambert Quetelet (1796-1874). His principal work, +_On Man and on the Development of his Faculties, An Essay on Social +Physics_, contains an account of his statistical researches on the +development of the physical and intellectual qualities of man and on +the ‘average man’ both physically and intellectually considered. He +followed this in 1848 by his treatise, _On the Social System and the +Laws which govern it_. In it he shows how the numbers representing the +individual qualities of man may be grouped round the numbers referring +to the average man in a way corresponding to the principles of the +theory of probabilities. This conception, elaborated and further +analyzed, has formed the basis of all subsequent researches in vital +statistics. + + +§ 10. _Military, Naval, and Prison Medicine._ + +The eighteenth century saw some of Petty’s principles put into +practice. There was, as yet, but one section of public life in which +scientific principles of preventive medicine could be applied. Only +in the Army and Navy were the sufferers from disease under adequate +control and observation, and only there were proper statistics of +sickness and health available. Thus, many of the most important +movements in Preventive Medicine during the eighteenth century, both +in England and other countries, were initiated by naval and military +surgeons. + +Among military medical reformers an important place is taken by a +Scottish pupil of Boerhaave, Sir John Pringle (1707-82). He had a large +military experience in the British army, occupied a position of great +influence, and was able to get many of his views and reforms generally +accepted. Pringle was among the first to see the importance of ordinary +putrefactive processes in the production of disease, and quite the +first to apply these principles in hospitals and camps. Important +conclusions on these matters were published in his _Experiments upon +Septic and Antiseptic Substances, with Remarks relating to their Use +in the Theory of Medicine_, which appeared in 1750. He identified +‘gaol fever’ or typhus with ‘hospital fever’. He laid down important +rules for the hygiene of camps which involved avoidance of marshes, +proper drainage, and adequate latrines. His most permanent service +was probably his suggestion that army hospitals should be regarded +as neutral, and be mutually protected by belligerents. This great +physician is a good illustration of the ‘new humanity’ which came into +public life in the eighteenth century. In much of that movement one may +feel the influence of that most humane of physicians, Hermann Boerhaave +(pp. 140-1). + +Hardly less important than the work of Pringle for the Army was that +of his brother Scot, James Lind (1716-94), for the Navy. Lind was a +pupil’s pupil of Boerhaave. He had a long naval experience and in 1753 +wrote an important work on Scurvy, then a very common and fatal disease +at sea. He demonstrated how this might be prevented by the adequate use +of fresh fruit or, when this was not available, of lemon juice. Fresh +water had always been a difficulty of sea voyages. Lind arranged for +sea-water to be distilled for the purpose. He introduced rules for the +prevention of typhus on ships, and made great improvements in naval +hygiene. His essay of 1757 _On the most effectual means of preserving +the Health of Seamen_ is a classic. He also wrote an important _Essay +on Diseases of Europeans in Hot Climates_, which opened the campaign +for the conquest of the tropics (p. 270). + +Lind, like Pringle, is one of a type that is very fully represented +in the eighteenth century. A worthy representative of that school +was Captain James Cook (1728-79), the explorer, who adopted Lind’s +principles. He established a record in one of his voyages to the South +Seas. The voyage lasted three and a half years, and many hardships had +to be endured, but out of 118 men only one died, and he was consumptive +when he embarked from England. Of a different type was the Manchester +health reformer, Thomas Percival (1740-1804), who worked to introduce +the reforms of Pringle and Lind into civilian life. The work of +Percival leads on naturally to Southwood Smith and Chadwick (pp. 193-5). + +The eighteenth century was essentially a period of individual effort. +The time was not yet ripe for public action on a large scale in +matters of Hygiene. Pringle, Lind, and Percival had, however, their +humanitarian parallels among prison reformers. Scientific attempts to +improve the ventilation and sanitation of prisons had been instituted +by the Rev. Stephen Hales (pp. 146-7). None brought greater devotion +to the task than John Howard (1726-90), a native of London who spent +his vigorous powers in investigating the prison system. His researches +extended to the hospital, quarantine and prison systems of France, +Flanders, Holland, Germany, Italy, Greece and Turkey (Fig. 88). His +reports were directly instrumental in the improvement of the hygiene +both of prisons and hospitals, as well as in the institution of +special fever hospitals in many countries. Some aspects of Howard’s +work were carried on by the great Quaker philanthropist Elizabeth Fry +(1780-1845), others came within the field of activity of Southwood +Smith and Chadwick (pp. 193-5). + +The eighteenth-century humanitarian movement was active and had many +able representatives in the United States. Foremost among them was +Benjamin Franklin (1706-90), while in the ranks of Medicine none takes +a higher place than Benjamin Rush of Philadelphia (1745-1813). Rush +was particularly revolted by public punishments, to the abolition of +which he devoted much energy. In matters of Hygiene Rush was ahead of +his time. He wrote on the hygiene of troops and laid special stress +on fresh air and cleanliness of body and mind as an aid to health. He +had a peculiar horror and repulsion for alcoholic intemperance. He +was responsible for the first systematic work on insanity published +in America. He left a fine account of a Yellow Fever epidemic at +Philadelphia, and he approached the truth in his view that the disease +arose in Philadelphia itself and was not brought as an infection from +without. + +[Illustration: FIG. 88. AN EIGHTEENTH-CENTURY QUARANTINE STATION +(Naples). + +From John Howard’s _An Account of the principal Lazarettos in Europe_, +Warrington, 1789.] + + +§ 11. _The Industrial Revolution._ + +During the eighteenth century the character of English civilization +became modified by a factor which has since profoundly influenced all +civilized countries. There was a rapid increase in the number and size +of the towns. The main cause of this was the transformation of Industry +by the use of mechanical power. The change that resulted in the life +and outlook of the people was very profound. These changes and the +causes that gave rise to them are usually spoken of as the ‘Industrial +Revolution’. That revolution had effects that were both wider and +deeper than followed any other such single upheaval in history. With +the mechanical elements that were at the back of the Industrial +Revolution, such as the improvements in transport, the invention of +industrial machinery (Fig. 90), the enclosure of common land, the new +position of agriculture, we are not here directly concerned. What does +affect our story is the increasing urbanization of the population, +which began early in the eighteenth century, increased rapidly soon +after the middle of the eighteenth century, and has progressed +continuously ever since. In this matter England is but a type, +for all other civilized countries followed in her wake, though at a +somewhat later date. + +Along with the growth of towns and the increased population there was +an increased demand for food. The country became better cultivated and +better drained, and there were many improvements in agriculture. Thus, +certain diseases began to diminish, notably Malaria, essentially a +disease of undrained and ill-cultivated lands. The expulsion of this +disease, as of Typhus, was the work of the nineteenth century (p. 283). + +It is often assumed that the physical evils of life became accentuated +by the rise of the great towns. Nevertheless, investigation shows +that the opposite has been the case. During the eighteenth century +men and women began to crowd into the great towns from the country. +They were, in fact, right in their choice, for their chances of life +there were greater than upon the land. In the rural districts infamous +housing conditions, an overcrowding beyond anything which we now +encounter, exposure to weather, uncertainty and fluctuation in the +prices of commodities, low wages, unpassability of roads in winter +time, inaccessibility of medical aids, combined to render life, and +especially child life, more precarious than in urban areas. + +[Illustration: + +FIGS. 89 and 90 illustrate the passage of the textile trade from home +industry to factory work with the consequent break-up of the family as +the labor unit. Textiles were the first important articles of commerce +to be thus affected, but others rapidly followed. The pictures are +typical of the Industrial Revolution. + +] + +The improvement of hygienic conditions in the towns began in England +soon after the middle of the eighteenth century. Westminster obtained +an Improvement Act in 1762, Birmingham in 1765, the City of London in +1766, Manchester in 1776, and most of the other provincial towns soon +followed. As a result of such Acts noisome streams which were but open +drains were covered in, the streets were paved and lighted, and the +sewers improved. There were still many glaring defects of sanitation +which have occupied and still occupy reformers, but by the end of the +eighteenth century the general appearance of a street in one of the +more advanced cities was much what it now is. The change from the +medieval conditions of a century before was at least as great as the +changes that have since taken place. + +[Illustration: + +FIG. 91 shows how the population of England and Wales started to +increase rapidly about 1750, with the beginning of the Industrial +Revolution. The chart covers a period in which statistics were not +exact. The figures for it have had to be estimated, but they are +probably accurate as round numbers. The census returns are available +from 1801. + +] + +[Illustration: + + 1910-12 + _Age_ 1730-9 1740-9 1750-9 1760-9 1770-9 1780-9 1790-9 _Males_ _Females_ + 10 36·9 37·0 37·3 36·9 36·7 37·5 38·2 -- -- + 20 29·1 28·9 29·2 29·3 29·4 29·9 28·4 42·35 46·71 + 30 23·7 23·5 23·8 24·1 24·1 24·9 24·4 33·87 37·94 + 40 19·6 19·2 19·4 19·6 19·5 19·5 19·5 26·03 29·67 + 50 16·1 15·8 15·7 16·1 15·9 15·7 15·8 19·09 22·17 + 60 12·2 12·4 12·1 11·9 11·9 12·0 11·9 13·09 15·39 + 70 9·4 8·6 8·7 8·5 8·3 8·7 8·5 8·17 9·57 + 80 5·9 5·7 5·7 5·7 5·7 6·3 6·2 4·79 5·39 + +Showing the expectations of life in London for each decade from +1730-1800, with recent data for comparison. + + _Age_ 1730-9 1740-9 1750-9 1760-9 1770-9 1780-9 1790-9 1911-12 + 10-20 6·5 5·9 5·9 7·1 8·2 7·1 6·5 -- + 20-30 17·5 17·6 17·2 17·9 17·3 16·4 15·1 3·7 + 30-40 27·1 26·3 26·1 25·2 25·0 23·9 23·7 6·2 + 40-50 36·6 38·6 35·9 36·3 35·5 35·4 34·3 11·7 + 50-60 45·5 47·9 45·7 42·1 45·0 44·7 44·6 21·1 + 60-70 61·4 63·4 63·7 64·4 62·8 64·7 64·1 40·3 + 70-80 83·7 98·3 96·4 101·8 105·0 101·7 104·4 87·3 + 80-90 143·1 150·4 151·0 153·0 152·7 153·0 155·1 181·9 + +Showing the death-rates at Age groups in London for each decade from +1730-1800, with recent data for comparison. + +FIG. 91A. TABLES showing that vital conditions in the eighteenth +century did not deteriorate but improved with the Industrial +Revolution. ] + +But if the streets had improved there was much under and around them +which would horrify us now. Water-supply, as in London, was usually +drawn mainly from surface wells and rivers. In most towns a continuous +water-supply was unknown. Even when water mains existed, the supply +to the houses was limited. Thus, even in the early nineteenth century +London houses had a water-supply only three times a week, and then only +for a few hours at a time. The water mains were often defective, and +there was not always that clear distinction between a water main and a +sewer that we now regard as desirable. Floods were a constant trouble +in all riverside towns. Cesspools were in use even in London as late as +the middle of the nineteenth century, and water-closets did not become +general, even in the better houses, until about 1828. The methods of +disposal of sewage hardly bear relation. In London the sewage simply +polluted the rivers. + +The improvement of such conditions as these could only be made by State +action. The eighteenth century did well where individual activity +was concerned. It was reserved for Southwood Smith (p. 193) and +Chadwick (p. 194) to introduce into the sphere of practical political +action the truth, set forth by Bentham (pp. 190-2), that all factors +which influence the health of the country must be the concern of the +Legislature. + +We gladly pass from this darker picture to the Hospital and Dispensary +Movement which took its rise about the middle of the eighteenth +century. Many of the great hospitals both in England and in Continental +countries were either founded or rebuilt about this time. Thus, the +London Hospital was rebuilt in 1752, St. Bartholomew’s in 1730-53. +Between 1700 and + +1825 no less than 154 hospitals and dispensaries were founded in +the British Isles. Though defective from the modern point of view, +yet under the influence of the sanitary reformers, Hales (p. 146), +Pringle (p. 169), Lind (p. 170), and Percival (pp. 170-1), these were +incomparably better equipped, better ventilated and better found than +such institutions would have been at the beginning of the eighteenth +century. The notes of the industrious Howard (p. 171) give us a very +complete picture of them, and one that is more favorable than might, +perhaps, have been expected. + +A defect of the hospitals of the time was certainly the nursing. +This, however, was somewhat better in the Lying-in-Hospitals, where +the services of a higher type of woman were available and where +ladies served on the committee of management. The general state of +the hospitals remained much the same until transformed by the changes +in surgery and nursing in the second half of the nineteenth century, +though a number of special fever hospitals and pest-houses were +established. + +Something must be said of the more prevalent diseases of the Industrial +Revolution. Stress is often laid on the effect of urban conditions +on child life. Yet there can be little doubt that historically the +movement has been beneficial to it. This comes out well in the +death-rates. Thus, in England in the period around 1740, before the +industrial revolution had begun, about 75 per cent. of children born +died before the age of five. In the period around 1800, when the +industrial revolution had set in, the percentage of deaths had fallen +to about 41. In the period 1915-24 it was about 14. Among the most +characteristic diseases of children is Rickets. It is very difficult +to trace the early history of this disease, but its incidence seems +to have been very high about 1700, and to have fallen progressively +throughout the eighteenth century. This fall, it has been suggested, +was due to agricultural improvements which led to better supplies of +better-fed meat. It was these improvements and better supplies that, in +their turn, made the big towns possible. + +We have already spoken of Scurvy on ships. It was, however, well known +on land, especially in winter when green vegetables were not to be +had. Lind (p. 170) in 1753 found it common in the land population. The +advances in agriculture removed it altogether from the land diseases +during the eighteenth century. + +[Illustration: FIG. 92. ST. BARTHOLOMEW’S HOSPITAL AT SMITHFIELD, +LONDON, in 1720.] + +[Illustration: FIG. 93. A VIEW OF THE PEST HOUSE in Tothill Fields, +London, in 1796. From a print in the British Museum.] + +§ 12. _Control and Recognition of Epidemic Diseases._ + +Over one department of public health there was State supervision +during the eighteenth century. The ports were guarded against the +introduction of Epidemic Diseases, and especially against Plague. +Throughout the eighteenth and early nineteenth century there was Plague +in the Near East which extended at times to various parts of Europe. +It was epidemic in Russia in 1709 and some 150,000 died of it. In 1719 +it spread to Eastern Central Europe. One historic outbreak was at +Marseilles and Toulon in 1720, when 90,000 died. The outbreak caused +great alarm in England, but did not reach this country, nor has there +since been any outbreak here. Quarantine is now regarded as antiquated, +vexatious, inhumane, expensive, and ineffectual. It seems probable, +however, that during the eighteenth century, when drastically enforced, +as in France with the Marseilles epidemic, it had indeed the effect +of keeping the disease within bounds. Incidentally, it led to the +foundation of many plague hospitals or Lazarettos, of the conduct of +some of which Howard (p. 171 and Fig. 88) speaks well. + +During the eighteenth century Small-pox was never absent from this +country. From time to time the disease became epidemic, and there +were grave and fatal outbreaks. Thus, in 1774 there was an outbreak +of small-pox at Chester. Next year an investigation was made of the +degree to which the population had suffered. It was then found that +before the outbreak there were in Chester only 15 per cent. who had +not already had the disease. The incidence on those unprotected by a +previous attack was 53 per cent., with a death-rate of about 17 per +cent. of those actually infected and of about 9 per cent. of the entire +unprotected population. + +With the certainty of contracting small-pox before their eyes, men +sought a way of getting it in a mild form. Outbreaks of small-pox +varied greatly in virulence, and infection with a mild form would +lead to protection from a graver one. In the East a method of direct +inoculation of the disease from a patient suffering from a slight +attack was widely in vogue from an early date. The practice attracted +little attention in Europe until Lady Mary Wortley Montagu (1689-1762) +studied it at Constantinople. It was then soon taken up in England, and +became recognized on the Continent. + +The efforts of Lady Mary in England were reflected on the other side of +the Atlantic. The famous Puritan leaders, Increase Mather (1639-1723) +and Cotton Mather (1663-1728), turning from their exploits against +the witches, ardently urged the operation. In England the learned +Dr. Richard Mead (1673-1754), an eminent and far-seeing physician +who exercised very great influence on the medical world in his day, +published in 1747 a work in which he supported the practice of +inoculation with all the weight of his authority. During the subsequent +half-century the practice spread widely. The operation was largely in +the hands of specialists who were not always medical men. + +Such was the state of affairs when the country practitioner Edward +Jenner (1749-1823) came upon the scene. In 1796 a dairymaid became +infected with a disease of the udders of cows, distantly resembling +small-pox. She developed pustules on her hand. Jenner inserted a +little of the matter from one of these into the arm of a boy of eight, +who developed typical cow-pox. Jenner next inoculated this boy with +small-pox, which, however, failed to develop. The evidence, so far as +it went, was complete. It is an entire justification of what might seem +nowadays to be a reckless experiment, that at that time inoculation +of small-pox was a normal and effective defensive procedure. The +disease of cows has since become known as Vaccinia, and the process of +inoculating it as _Vaccination_. + +[Illustration: + +FIG. 94. HAND OF DAIRYMAID infected with cow-pox from a cow’s udder. +From Edward Jenner, _Inquiry into the Causes and Effects of the +Variolae vaccinae, a Disease discovered in some of the Western Counties +of England, particularly Gloucestershire, and known by the name of the +Cow Pox_, London, 1798. + +] + +The discovery of vaccination, important though it be, is a mere +trifle compared to the train of new work and new thought that has +been opened out by it. The whole study of Immunity, which has now +become an independent science, arises from it. The work of Pasteur (p. +225), Lister (p. 239), and Koch (p. 234), and a large part of modern +therapy, are among the achievements of this movement. + +Besides Plague and Small-pox, many other epidemic diseases became more +clearly understood during the period we are considering. Among these +was Scarlet Fever, the history of which is particularly interesting +for the variations which it has shown in virulence. It first became +clearly recognizable as a mild disease without prominent symptoms about +1650. Good observers in the half-century that followed considered it a +new disease. In England it continued to be of little importance till +about 1748, when it began to be associated with grave throat symptoms +and to be confused with Diphtheria. This phase continued for about ten +years. The virulence then dropped and the disease continued of slight +consequence till 1785. It then grew virulent again and remained so till +about 1808. The malignancy then fell again and remained low for about +thirty years. It rose about 1837 and from then till 1884 it was one of +the great killing diseases, especially of childhood. Since then, the +mortality from it has steadily decreased. + +During most of its history Scarlet Fever has been liable to greater +or less confusion with Diphtheria. The clinical distinction was first +clearly made in 1826 by Pierre Bretonneau of Tours (1771-1862), who +gave Diphtheria its present name. The same French physician performed +the first successful tracheotomy in a case of Diphtheria. He is also +known for pioneer work in the recognition of Typhoid Fever. + + + + +VI + +PERIOD OF SCIENTIFIC SUBDIVISION + +(FROM ABOUT 1825 ONWARDS) + + +§ 1. _Origins and Implications of Scientific Specialization._ + +We have seen how the philosophy of Newton, with its implication, the +Reign of Law, which is the Uniformity of Nature, has come to pervade +scientific thought (p. 137). Now, before Newton as after him, there +were certain natural divisions of scientific activity corresponding, +in some degree, to the types and faculties of men. Since Science +first began there have been Mathematicians, Biologists, Physical +Experimenters, because in fact the particular powers which enable +a man to reach distinction in one of these departments are of less +value in the others. Until the period of which we are now to treat, +investigators were accustomed to explore at large within these great +departments. Such specialist professions as Actuarial Calculators, +Economic Entomologists, Physical Chemists, or, in the department +of Medicine, Medical Statisticians, Aural Surgeons, or Vaccine +Therapists--familiar to us now--were unknown and undreamt of then. This +subdivision is a new thing, and is a characteristic product of the +period of which we have now to treat. The subdivisions, unlike those +of old, are largely artificial. Thus, the Aural Surgeon who deals with +the organ of hearing cannot be separated clearly by his training, his +powers and faculties, his operative skill, nor even perhaps by his +field of work, from the Stomatologist who deals with the mouth, or +the Rhinologist who deals with the nose. Nevertheless these minute +subdivisions are convenient and beneficent in medical as in other +departments. The question of scientific specialization is so important +and characteristic that we must examine it a little farther. + +It is often thought that, since no man can compass all knowledge, +this scientific subdivision is merely an attempt to compass a part +of that growing mass of knowledge which is becoming progressively +less compassable in its entirety. The movement, however, both in +origin and development, is less simple than this, for there never +was a time when a man could know all that was known about his world. +In this respect our own age is even as other ages. Were the view +philosophically tenable--which it is not--that Science becomes yearly +less comprehensible, our outlook would be gloomy indeed. For since +there is no evidence of any increase in the mental capacity of the +human race--at least in historic time--such a view would imply a +progressive diminution in the number of those competent to treat any +wide scientific area, and a corresponding progressive separation +from each other of minds with scientific insight. Fortunately such +conditions do not prevail; the view that they do is simply due to a +gross, yet widespread, misconception of the nature of Science. + +Equally fallacious is the idea, which has become diffused by the +existence of scientific specialization itself, that the progress of any +science is to be measured by the mass of observations that its votaries +have succeeded in accumulating. This is far from being the case. The +advance of a science is measured by the degree with which it succeeds +in bringing a multiplicity of observations under general laws. Judged +by this standard, we should probably rate very highly, for example, +the present state of what is called _Demography_, the study of the +life conditions of communities, while we should rank much less highly, +for example, the present state of the study of Aural Surgery. Yet, for +one publication on Demography there must be many on Aural Surgery. +In the one case, however, the accumulation of knowledge follows a +well-directed and rational scheme. In the other it is prompted and +occasioned by the immediate needs of individual sufferers. This must +not be considered as derogatory to those whose task it is to treat +the sufferers. The point is that the one department, of its nature, +exhibits the rational spirit better than does the other. + +Since Rational Medicine is the subject that we treat here, we shall +select for discussion those departments which best illustrate +its spirit. This does not imply, and is not meant to imply, any +belittlement of the less fortunate departments. On the contrary, the +less any scientific department has succeeded in eliciting general laws, +the more necessary it is that those most capable for the prosecution of +such advance should devote their attention to that department. It may, +indeed, reasonably be urged that a leading defect in our scientific +organization is that men of scientific insight crowd to just those +studies where their special powers have already been best exhibited. + +In previous chapters, dealing with more remote times, we have been able +to place our facts in historic perspective. Despite the enormous mass +of scientific literature dating from the seventeenth, eighteenth, and +early nineteenth centuries, there is no real obstacle to selecting +what is most important in it. True, it is beyond the power of any +one student to examine all this literature at first hand, but it has +been arranged and indexed, posterity has passed its verdict, and the +historian can find his way through the thicket. It is also true that +important advances are sometimes forgotten, as happened to Mayow’s +discovery of Oxygen in the seventeenth century (pp. 126, 151), which +was repeated by Priestley a hundred years later (p. 154). But the +fact that we know of such neglected discoveries shows that, however +unjust the fates may have been to Mayow, yet his influence has not been +underestimated by later historians. The History of Science, therefore, +can up to a certain point be written along the same lines as political +or economic history. + +The face of affairs changes, however, when we pass into a period which +differs for different topics, but may be roughly defined as beginning +somewhere between about 1820 and about 1870. We then begin to encounter +the very questions with which men of Science are occupied in our own +time. Since many of these questions still remain unsettled, it is +impossible for the historian to say with certainty which are the most +fruitful lines of work. The most he can hope to do is to distinguish +the most influential and stimulating thinkers and observers from those +who have been less so, and to say something about the ideas with which +the more important schools of thought were instinct. + +When we look into the origin of the system of specialization, whether +in Medicine or in any other department of Science, we shall find +certain philosophical tendencies at work of which the modern man of +Science is the heir, though often the unconscious and sometimes the +ungrateful and even the misunderstanding heir. Neither men of Science +nor medical men are always philosophers, or at least not always +consciously so. Nevertheless, they are as surely influenced by the +streams of thought of their time as they are by their heredity and +their physical environment. The general tendencies of Medicine in this +or in any other age cannot be interpreted without some reference to +the intellectual atmosphere in which it has arisen and in which it has +flourished. + +The intellectual atmosphere in which scientific specialism arose was +that of the so-called ‘Utilitarian Philosophy’. Many of the dicta +of that school, which came into prominence toward the end of the +eighteenth century, are still used as part of the language of men of +Science and others. ‘The greatest happiness of the greatest number’ +is a formula launched upon our common speech by Joseph Priestley +(1733-1804, p. 154). The pursuit of such happiness as the main object +of human activity is taught by the ‘Utilitarian’ philosophy, a word +coined by the English political and social thinker, Jeremy Bentham +(1748-1832). To Bentham, the founder of that philosophy, we owe such +useful additions to our language as ‘codification’ and ‘international’, +and these, together with ‘utilitarian’, give us some clue to the +character and mode of his thought. It is probable that no thinker had a +larger share than Bentham in ushering in the era of the subdivision of +the sciences. + +Bentham made a sustained attempt to draw a parallel between the +physical and the social sciences, and this gave him a special +influence over medical thinkers and especially over those that dealt +with the public health. His pupil, John Stuart Mill (1806-73), speaks +of his master’s mode of working as ‘the chemical method’. It is +thus not remarkable that Bentham should exert a profound influence +on Medicine, both directly and indirectly. The peculiarly logical, +uncompromising and perhaps un-English character of his mind, while it +prevented him, fortunately for himself, from taking an active share in +the task of government, did not prevent him from influencing those who +did. Specifically, he is the direct begetter of our modern system of +organization of the Science of Preventive Medicine. + +[Illustration: + +FIG. 95. A CARTOON OF THE EARLY NINETEENTH CENTURY illustrating the +condition of children in the factories of the time. A bale is directed +to Sir Robert Peel. This is the first Baronet (1750-1830), father of +the statesman. Peel the elder was a cotton-spinner who imported from +the London workhouses deserted children whom he treated well, but used +to work his factories in Lancashire. He was a Member of Parliament +and in 1802 carried the Act which was the forerunner of all factory +legislation, _An Act for the Preservation of the Health and Morals of +Apprentices and others, employed in Cotton and other Mills_. + +] + + +§ 2. _The Revolution in Preventive Medicine._ + +Of all the many changes in Medicine and Medical thought that the +Period of Scientific Subdivision has witnessed, none have been +more revolutionary than those in the department which deals with +Preventive Medicine. Great and important reforms were introduced +during the course of the eighteenth century. These, however, even +when the result of legislation, were the outcome of the effort of +individuals, or were concerned with the Army and Navy (p. 169). In the +period that follows, the Public Health becomes a general political, +legislative, and administrative matter, and ‘Prevention’ becomes its +watchword. The public consciousness--moralists will call it the public +_conscience_--had been aroused, and has never again entirely slept. The +chief agent in the awakening process, the intellectual force at its +back, was and is Jeremy Bentham. + +Rational Medicine has, in general, no national frontiers. To it men +of all the national units have made important contributions. But the +care of the Public Health in the period on which we now enter, being +an affair of legislation and administration, has developed along +national lines and it is difficult to discuss it save on a national +basis. It is a source of justifiable national pride that Britain has, +from the first and throughout, been the leader of the Public Health +movement. But while we lose little and gain much by telling the story +from the British point of view, it has still to be remembered that, +just as Rational Medicine has, fortunately, no spiritual frontiers, +so, unfortunately, sickness and suffering have no physical frontiers. +Epidemics pass the most scientifically constructed boundaries upon the +surface of the map, and without a passport. In our time this evident +proposition has obtained, at least, formal recognition. International +health legislation has at last appeared. A future historian of Rational +Medicine will be able to write his chapter on the Public Health +from the point of view of Humanity at large. The historian who has +the misfortune to be born too early must still content himself with +treating the subject along national lines. + + +(a) _Preventive Medicine in Britain._ + +If Bentham be the spiritual father of Public Health legislation, the +protagonists whose names must be associated with the development of the +movement along practical lines in England are Thomas Southwood Smith +(1788-1861) and Edwin Chadwick (1800-90). + +Thomas Southwood Smith was a Unitarian minister, and long combined this +office with that of physician. Settling in London in 1820 he came under +the influence of Bentham. By his essay on _The Use of the Dead to the +Living_ he did something to remove the odium attached to dissection. +The scandals of the time and the common sense of the ‘utilitarians’ +(p. 190) led to the passing of the Anatomy Act of 1832. Thus by a +proper legal process bodies became available for dissection by medical +students. Bentham died just before this Act became law and by his will +left his body to Southwood Smith to be the subject of dissection and +of an anatomical lecture. + +Southwood Smith’s services to the spread of interest in Public Health +were very numerous. He circulated a simple and popular _Philosophy of +Health_ (1835). He served on a board of inquiry as to the condition +of children in factories (1832, cp. Fig. 191), and he was especially +useful to the Poor Law Commissioners by reason of his exceptional +knowledge of fevers. He was the founder of a ‘Health of Towns +Association’ (1840), and of another association for ‘improving the +Dwellings of the Industrial Classes’ (1842). In 1848 he became a member +of a new government department, the ‘General Board of Health’ (p. 195). +His official reports on Quarantine (1845), Cholera (1850), Yellow Fever +(1852), and on the results of sanitary improvement (1854), were of +world-wide use. + +Edwin Chadwick (1800-90), who was not a medical man, introduced to +public notice what he called the ‘sanitary idea’, a conception that +colored the whole of his extraordinarily active life. He sat on +Government Commissions on Poor Law, on Police, and on the investigation +of the condition of factory children. One of his Reports (1833), issued +while he and the century were both in the early thirties, recommended a +system of inspection with a view to limiting children’s hours of work. +The current system of pensions and of trade instruction to soldiers and +sailors is the descendant of a scheme of Chadwick’s devising. An item +in the evidence attached to one of his Reports is the public provision +of open spaces for recreation, a topic of current interest at the +moment of writing. + +At the time of the accession of Queen Victoria in 1837 Chadwick was +agitating for the appointment of a Sanitary Commission. Two years +later, as a result of a grave epidemical outbreak in London, the +Commission was appointed. Its reports, which drew wide attention at +the time, have had a large share in determining the general course of +health legislation in the ninety years that have since elapsed. The +scientific basis of health legislation can only be determined if proper +vital statistics be available. The Registration Act of 1838, under +a developed form of which we still live and die, was in essence his +work. If we search into the history of any department of the scientific +treatment of the Public Health, we shall always ultimately work back +either to Southwood Smith or to Chadwick and through them to Bentham. + +Among the most important documents for which Chadwick was responsible +was the _Parliamentary General Report on the Sanitary Condition of the +Labouring Population of Great Britain_ (1842). It came to fruit in 1848 +with the _Public Health Act_, which established a new governmental +department, the ‘General Board of Health’ (p. 196). The same year saw +the passage of the _Nuisances Removal and Diseases Prevention Act_, +by which summary action in such matters was rendered possible on the +complaint of specially authorized local authorities. Just as the Board +came into action there was an outbreak of Cholera in England, of which +54,000 persons died. The statistics available under the new system made +possible the deduction that the infection is conveyed by drinking-water +and led to suitable precautions. This is one of the many instances in +which the practice of prevention of a germ-borne disease preceded +any knowledge of its organic cause, or indeed any direct knowledge of +disease germs at all. + +The first town in England to appoint a Medical Officer of Health was +Liverpool. The City of London followed in 1848, when Simon took office. +After Southwood Smith and Chadwick, Sir John Simon (1816-1904) was the +foremost figure in the history of the Public Health of this country. He +later became medical officer to the ‘General Board of Health’. The work +of this Board--together with its medical officer--was taken over, for +political and administrative reasons, by the Privy Council. The medical +department of the Privy Council became in 1871 part of the Local +Government Board, the medical functions of which were absorbed by the +new Ministry of Health in 1917. + +To Simon are due the abolition of urban cesspits and improvement of +the system of sewers, and the institution of sanitary inspectors and +legislation concerning housing and overcrowding. One important result +of these measures was that it became possible to abandon the cruel and +wasteful system of quarantine that had been of value in the eighteenth +century. Simon’s plan, which was gradually adopted, was to trust to +the same preventive methods for foreign as for native infections. This +was, of course, only possible with an efficient sanitary service such +as he succeeded in instituting. Such measures were aided by laboratory +investigations, begun by a small staff. At first largely occupied +with examinations in connection with actual outbreaks, its scientific +functions rapidly grew. Working on a wider basis, these functions have +been performed for the nation since 1911 under the direction of the +Medical Research Council. + +[Illustration: FIG. 96. ANNUAL DEATH-RATE IN LONDON PER THOUSAND LIVING +OVER A PERIOD OF 85 YEARS. + +It will be seen that the curve begins definitely to take a downward +trend about 1870. It has been falling ever since. It is now less than +half of what it was sixty years ago. This fall is largely, though +not entirely, due to decrease in infant mortality. Some of the more +important epidemics are indicated. Typhus disappears as an important +cause of death in the forties and Cholera and Small-pox in the sixties. +Since then the death-rate has been considerably influenced by Influenza +outbreaks. + +] + + +(b) _Preventive Medicine in the United States._ + +In the United States the history of the national Public Health Service +has been very different from that of the English system. The same +philosophical tendencies have been at the basis of the American as of +the English system. In the United States, however, the National Service +has been linked with the Army and Navy in a manner quite foreign to +British traditions. The Federal health system had its origin in the +old Marine Hospital Service, first authorized by Congress in 1798. +This enabled the President to appoint medical officers at ports and +elsewhere for the purpose of giving medical treatment to disabled +merchant seamen. The funds were obtained by a tax on those employed on +American vessels. + +The first marine hospital under the Act was at Norfolk, Va., in 1800. +In 1802 a marine hospital was built for the port of Boston, and from +time to time hospitals were built at other important seaports. To +provide for the relief of seamen on inland waters Congress passed in +1837 an Act for the appointment of a board of advisory medical officers +of the Army. A number of hospitals were established on its advice. + +The evolution of public health functions from this service was along +natural lines. The medical officers, in providing care for the +American merchant marine, were often the first physicians to diagnose +such diseases as Cholera, Yellow Fever, Small-pox and the like, +which were being imported into the United States. In the epidemics +of Cholera which occurred in certain ports of the United States the +marine hospitals and their medical officers were utilized for the +relief of those suffering from the disease. During the Civil War the +marine hospitals, together with the medical officers, were used by +the military authorities, both North and South, for the care of the +military forces. + +Not until 1878 did Congress authorize any extensive use of the Marine +Hospital Service as a Federal Health Service. An Act of 1878 gave +broad powers to the Service to co-operate with State and local health +authorities in the control of disease, especially of Yellow Fever. +In 1890 Congress decided to utilize the Marine Hospital Service as +the Federal Health agency for the prevention of inter-State spread of +Cholera, Yellow Fever, Small-pox and Plague. In 1893 the powers of +the Marine Hospital Service in this regard were extended to cover all +infectious and contagious diseases, in co-operation with State and +local health agencies. + +The efficiency of the Marine Hospital Corps in the control of epidemic +diseases became widely recognized. In 1889 Congress passed an Act which +made possible the further organization of the Marine Hospital Corps, +and provided that the officers be commissioned in grades similar to +those of the medical department of the United States Army. An Act +of 1875 had already provided that the Surgeon-General (supervising +surgeon) should be appointed by the President, with the consent of the +Senate. + +In 1893 the Marine Hospital Service was organized into the Federal +Health Service. Congress continued to impose additional health +functions upon the Service, and in 1902 changed its name to the ‘Public +Health and Marine Hospital Service’ and made it a health service in +name as well as function. The larger part of its duties, up to this +time, had been the combating of epidemics, especially those of Yellow +Fever, which from time to time swept the country. With the threat of +Bubonic Plague in 1900 at San Francisco, the Marine Hospital Service +was placed in charge of control methods and succeeded in preventing any +extensive spread of the disease. + +In addition to the quarantine and hospital functions, the activities +of the Service soon came to include research and educational work. In +1902 Congress authorized the establishment of the Hygienic Laboratory +for investigating Cholera, Yellow Fever, and other conditions. +The Laboratory grew rapidly and is now a very important research +institution, equipped for carrying on pathological, zoological, +pharmacological, bacteriological, chemical, and physiological work. + +From the control of epidemics, the Public Health and Marine Hospital +Service began to develop control measures for the more common +contagious and infectious diseases, such as Typhoid Fever, Diphtheria, +and Scarlet Fever. The history of the wonderful control of Typhoid +Fever which has taken place in the United States within the past +twenty years is a part of the history of the Public Health Service in +co-operation with State and local health agencies. Typhoid fever, which +formerly took a toll of more than 50,000 lives annually, is responsible +for the death of a mere fraction of this number at the present day. + +The development of health functions of the Public Health and Marine +Hospital Service continued until Congress in 1912 changed the name to +its present one, the ‘United States Public Health Service’, and at the +same time gave it broad powers to investigate the diseases of man and +the pollution of navigable streams and lakes. + +During the courses of Federal development the separate States of the +Union were not devoid of protagonists of State intervention in matters +of public health. Among these was Lemuel Shattuck (1793-1859), who, +like Chadwick, was no medical man, but a student of social problems. +Under the influence of Chadwick he drafted in 1850 the _Report of +the Massachusetts Sanitary Commission_. This publication set forth a +complete scheme of Public Health organization. The formation of the +first State Board of Health in Massachusetts was, however, delayed +till 1869. In this matter Massachusetts was, in fact, anticipated by +Louisiana, which obtained a State Board of Health in 1855, and by New +York City, which obtained a Board of Health in 1866. Most of the States +followed in the seventies. The seventies and eighties were the decades +in which the general principles suggested by the work of Pasteur and +Koch were put into effect. The working hypothesis of sanitarians +of the time was that filth and ill-drainage were direct factors in +the production of epidemic disease. The view is now untenable, but +there was unquestionably an immense improvement in health conditions +resulting both directly and indirectly from the improved drainage, +water-supply, housing, and the like that the agitation had stimulated. + +As the bacteriological discoveries of the time became generally +accepted, they were widely applied on American soil to the +administrative control of disease, notably by the New York Department +of Health under Hermann M. Biggs. That body, in 1892, instituted a +bacteriological laboratory, the scope of which has steadily increased. +Its work in connection with Diphtheria is elsewhere discussed (pp. +265-6). + +To follow into our own time the development of factory legislation, +vital statistics, school medical service, local health authorities, +municipal laboratories and clinics, methods of food inspection, would +be to write a text-book of Public Health Administration. In all these +developments we see working the rational spirit in the peculiarly +English field of Preventive Medicine. The spirit of Rational Medicine +cannot function, however, without material upon which to work. The +basis, the elementary matter, as it were, of that material, is the +conception we form of the nature of the bodily processes. Such +a conception it is the function of Physiology to provide and to +Physiology we therefore now turn. + +[Illustration: FIG. 97. THE OLD _DREADNOUGHT_ HOSPITAL SHIP. + +A ‘Seamen’s Hospital Society’ was founded in England in 1817. Its first +hospital was the _Grampus_, an old 50 gun ship moored off Greenwich. +This was succeeded in 1830 by the _Dreadnought_, 104 guns, and this +in 1857 by the _Caledonia_, 120 guns, renamed _Dreadnought_. In 1870 +this last wooden _Dreadnought_ was broken up and the patients were +transferred to a building on shore close by. The darkness, damp, +ill-ventilation, noisiness and septic character of a wooden ship made +it thoroughly unsuitable for hospital purposes. + +In 1899 the ‘Seamen’s Hospital Society’ established a special Hospital +and School for Tropical Diseases such as are peculiarly common among +seamen. ] + + +§ 3. _The Transition to a Physiological Synthesis._ + +Modern developments in physiological knowledge introduce an important +period in the History of Medicine, for the study of the functions of +the body is a natural portal of entry to the study of the perversions +and suspensions of those functions that we call disease. The general +character of physiological thought during the modern period may perhaps +be described as the ‘synthetic study of the animal body’. The study +has become synthetic because organs have not been studied so much in +and for themselves as in relation to other organs. There has been, in +fact, during the period, an increasing consciousness of the integration +of the organs into one organic whole, the entire process being under +the control of the nervous system, the various parts of which are +themselves integrated (p. 308). This movement has, to some extent, +mitigated the ever growing evils of scientific specialization. + + +(a) _Anatomy and Embryology in the Earlier Nineteenth Century._ + +Let us first glance at the state of anatomical knowledge in the early +and middle nineteenth century. The general structure of the animal body +was well known. Descriptive Anatomy was not far from where it now is. +Comparative Anatomy, which had made good progress, was given a fresh +impetus by the researches and by the authority of a brilliant group of +French investigators, headed by Baron Georges Cuvier (1769-1832), whose +influence spread to England, Germany, and America, where the leading +exponents were Richard Owen (1804-92), Karl Gegenbaur (1826-1903), and +E. D. Cope (1840-97). Cuvier was a biological dictator whose opinion +did much to encourage investigation, and something to discourage some +important investigators. His services to Comparative Anatomy can hardly +be overrated. There was, however, still no effective knowledge of the +anatomical differences between the races of man, while the species of +man and of allied forms, whose skeletons palaeontologists have since +described, were quite unknown. + +As regards knowledge of the process of Development of the animal body, +the broad lines of Embryology were being put on a firm basis by Karl +Ernst von Baer (1792-1876), whose work was finished in 1837, though he +lived another forty years. The subject was to be given a new meaning by +the evolutionary school, which applied to new details and to particular +instances the work of Charles Darwin (1809-82). Foremost of this school +was Francis Maitland Balfour (1851-82). + + +(b) _Chemical Physiology in the Earlier Nineteenth Century._ + +The analysis of the functions and workings of the body had advanced far +less than the knowledge of its structure. The study of Respiration was +perhaps in the best position. The elementary conception of Respiration +attained by Lavoisier at the end of the eighteenth century (p. 155) +was hardly extended till E. F. W. Pflüger of Bonn (1829-1910), in +the sixties and seventies of the nineteenth century, showed that the +essential chemical changes of respiration do not occur in the blood or +in the lungs, but in the tissues. + +A very important figure in the scientific world of the thirties and +forties of the nineteenth century was the German Justus von Liebig +(1803-73), professor of Chemistry at Giessen. He was a convinced +mechanist, and over the door of the University Laboratory which he +founded he had inscribed the dictum _God has ordered all His Creation +by Weight and Measure_. His great achievement was his application of +chemical knowledge to physiology. He did much to introduce laboratory +teaching, and certain apparatus which he invented is still in constant +use. + +Liebig greatly improved the methods of organic analysis and notably he +introduced a method for determining the amount of urea in a solution. +This substance is found in human blood and urine, and was the first +organic compound to be ‘synthetized’, that is to say, built up from +inorganic materials. It is of very great physiological importance. +This is due to the fact that it is regularly formed in the body in the +process of breaking down the characteristic nitrogenous substances +known as proteins. Along with his colleague, Friedrich Wöhler +(1800-82), who had already synthetized urea, Liebig wrote a famous +paper (1832) in which he showed, for the first time, that a complex +organic group of atoms--or ‘radicle’ as it is called--is capable of +forming an unchanging constituent through a long series of compounds, +behaving throughout as though it were an element. This discovery is of +primary importance for our conceptions of the chemical changes in the +living body. + +From 1838 onwards, Liebig devoted himself to attempting a chemical +elucidation of living processes. In the course of his investigations +he did pioneer work along many lines that have since become well +recognized. He taught the true doctrine, then little recognized, that +animal heat is the result of combustion, and is not ‘innate’ (compare +p. 156). He classified articles of food with reference to the functions +that he conceived they fulfilled in the animal economy. An outcome of +this was his food for infants and his extract of meat. Very important +was his teaching that plants derive the constituents of their food, +their carbon and nitrogen, from the carbon dioxide and ammonia in the +atmosphere, and that these compounds are returned by the plants to the +atmosphere in the process of putrefaction. This discovery made possible +a philosophical conception of a sort of ‘circulation’ in Nature. That +which is broken down is constantly built up, to be later broken down +again. Thus the wheel of Life goes on, the motor power being energy +from without, derived ultimately from the heat of the sun. + +It was very unfortunate that Liebig conceived and adhered to a totally +wrong view of the nature of putrefaction and fermentation, which it +took Pasteur long years to displace. + + +(c) _Nervous Physiology in the Earlier Nineteenth Century._ + +From Chemical Physiology we turn to glance at the knowledge of the +Nervous System. Charles Bell and his contemporaries (p. 145) had +attained to a clear distinction of the nature of motor and sensory +nerves and their separate origin from the two spinal roots (Fig. +98). The next fundamental contribution was made by Marshall Hall +(1790-1857), who established the difference between volitional action +and unconscious reflex (1833). + +The fundamental ideas in the conception of reflex action had already +been adumbrated by Descartes. In the view of that philosopher, any +stimulus is transmitted along nerve-fibers to the central nervous +system. There, on account of existing nervous connections, it gives +rise to a fresh impulse which passes along outgoing nerve-fibers +to the active organ, muscle, or gland, which is thereby excited to +activity (p. 128). Thus, every action of the organism, and its life +as a whole, conforms to definite laws. These laws must be directed +to its preservation, or organisms would cease to exist. It is thus +possible to look on organisms simply as elaborate mechanisms. Except +that we know that we ourselves think and feel, we might eliminate mind +from our consideration of the action of beings other than ourselves. +Such was the view taken by the mechanists and other members of the +iatro-physical school (pp. 127-131), which followed, to a greater or +less extent, the teaching of Descartes. The course of physiological +advance may be described, briefly, as the expulsion of the mental +element from process after process associated with vital activity. This +avenue leads on to a philosophical discussion whither we shall not now +follow. It will suffice, at the moment, to remind the reader that only +through the channel of _his own_ thinking and feeling is he able to +follow these physiological discussions at all. + +The conceptions of Descartes and of his successors were greatly +extended by Marshall Hall. Interest was lent to Hall’s work by the +contemporary discovery by French observers of what was regarded as a +special center governing respiration--a very important reflex--in the +lower part of the brain. Hall’s work gave ‘reflex action’ a permanent +place in Physiology. + +[Illustration: FIG. 98. DIAGRAM OF TRANSVERSE SECTION OF THE SPINAL +CORD AND THE MAIN NERVES DERIVED FROM IT.] + +[Illustration: FIG. 99. DIAGRAM TO ILLUSTRATE SIMPLEST FORM OF REFLEX +(cf. Fig. 98). + +An afferent impression from a sense organ to the spinal cord may give +rise to an efferent impulse by a purely intra-spinal process. This +impulse may be of the nature of a complex and balanced muscular act +involving a whole system of muscles, some of which may be antagonistic +to each other. All this may take place not only unconsciously, without +any intervention from the higher nerve-centers in the brain, but even +in an animal from which the brain has been removed. On the other hand, +channels exist (and are indicated in the diagram) for passage of +impressions to and impulses from higher centers. These higher centers +in many cases control or modify the resulting muscular or other action +to a greater or less degree. + +] + +Since Hall’s time there has been a great extension of the conception of +reflexes. It has been shown that, besides the simple nervous arc (Fig. +99), there are more complex nervous arcs which depend for their action +on the integrity of an elaborate mechanism. The nervous system is +‘integrated’ under higher and higher centers, till at last the highest +centers of the brain are reached (pp. 308-11). Many of the ordinary +acts of life, sneezing, coughing, standing, walking, even breathing, +are expressible as reflexes. The attempt has also been made to press +the ‘instincts’ into the same category. But it is difficult to separate +the instinctive from the volitional elements or to define either. Vast, +therefore, as is the development of this department of physiology, it +is a very delicate task for the historian to pass any verdict upon it. +The ultimate value of all this work must depend upon the conception +that the next generation attaches to the mental element in vital +phenomena. There is evidence of reaction at the present time from the +extreme mechanist physiological position. + +Lastly, in the discussion of work on the nervous system comes the +question of the localization of functions of the brain. The possibility +of such localization is a very ancient speculation. The idea was +developed along rational lines, in the first third of the nineteenth +century, by certain Viennese workers who, having made important +contributions to science, unfortunately afterwards degenerated into +phrenological quacks. Later several German observers began the study of +the electrical excitation of those parts of the cortex of the brain +which specially control movement (Fig. 100). The work was continued and +developed by a number of distinguished French and English observers, +among whom Paul Broca (1824-80), Hughlings Jackson (1834-1911), +and Sir David Ferrier (1843-) should be commemorated. Under their +influence many operations usually regarded as involving complex mental +processes, such as vision, speech, reading, writing, drawing, have been +represented as depending on simple nervous relationships. Centers for +the initiation of these operations have been described. Of late years, +there has been reaction from this mechanical conception of the brain as +an organ of the mind. The older school has, however, achieved clinical +success especially at the hands of the great French physician Jean +Marie Charcot (1825-93) and his pupils. + +[Illustration: FIG. 100. DIAGRAM TO ILLUSTRATE SOME OF THE MAIN FACTS +OF CEREBRAL LOCALIZATION.] + + +§ 4. _The Experimental Foundations of Modern Medicine._ + +We may turn back to consider those who have been the immediate +progenitors of modern Physiology. Among these, three men stand out +beyond all others. In order of seniority, and perhaps of genius, they +are Johannes Müller, Claude Bernard, and Karl Ludwig. + + +(a) _The Work of Johannes Müller._ + +Johannes Müller (1801-58) was the greatest physiologist Germany has +produced, and perhaps the greatest physiologist of all time. His +genius was of the universal type and, despite his early death, he +attained equal distinction in every department which he touched. Among +these were Comparative Anatomy, Embryology, Physiological Chemistry, +Psychology and Pathology. He was a careful scholar, well versed in the +history of the subjects which he taught, and as great a teacher as he +was an investigator. A very large number of the best-known men who have +advanced Medicine during the nineteenth century were his pupils while +he was a professor at Berlin. His lovable character was pervaded by a +mystical tendency. + +Müller’s text-book of Physiology began to appear in 1834. It introduced +into the subject the comparative and psychological points of view, +which were not fully appreciated until the generation that followed. +The most remarkable generalization associated with his name--and +one further developed by Ewald Hering (1834-1918)--is the ‘Law of +Specific Energies’. According to this law each sensory nerve, however +stimulated, gives rise to its own specific sensation and to no other. +Conversely, the same stimulus applied to different organs of sense +produces a different sensation in each organ--that sensation, in fact, +that is its specific attribute. Thus electrical, mechanical, thermal +stimulation produce only the sensation of light when applied to the +optic nerve. On the other hand, any particular form of stimulation, for +example electrical, produces sensations of light, smell, hearing or +taste if applied to the appropriate nerves. + +A moment’s reflection will enable the reader to realize the very +great philosophical importance of these conclusions. They provide +experimental evidence that the things of the external world are not +in themselves discernible by us. Such external things we know only by +the events to which they give rise acting on our senses, and yet from +one and the same event utterly different sensations arise within us. +To beings with senses different from ours the world also would be +different. The ‘Law of Specific Energies’ is thus fundamental for our +view as to the range of validity of Scientific Method. + +Among other important contributions of Johannes Müller to the +physiology of the nervous system were his experimental confirmation +of Bell’s researches on the spinal roots (p. 145) and his experiments +on the production of the voice. He launched important theories in +explanation of color vision, of the mechanism of hearing, and of the +phenomena of fever. He was one of the first to use the microscope in +pathology and he was one of the founders of Physiological Chemistry. + +Like every investigator Müller made mistakes. In 1840 he stated that +the velocity of a nervous impulse could never be measured. By 1852 his +gifted pupil, Hermann von Helmholtz (1821-94), had measured it. Much of +Helmholtz’s work hardly comes within our department. He was, however, +inventor of the instrument known as the _Ophthalmoscope_, by means of +which the interior of the eye can be examined. This is the main factor +which has enabled Ophthalmology to develop along true scientific lines +(p. 319). + + +(b) _The Work of Claude Bernard._ + +Claude Bernard (1813-78), the great French physiologist, was Müller’s +junior by twelve years and was in almost every respect a contrast to +him. His mind was of that peculiarly French type to which anything +mystical is abhorrent. He had few eminent pupils who owed much to +him directly, but the influence of his ideas, through his writings, +can hardly be exaggerated. Especially Bernard was the founder of +‘Experimental Medicine’, that is of the artificial production of +disease by chemical and physical means. This is one of the most +important scientific movements within our field. + +Bernard’s great discovery, which occupied him for over ten years, +was that the liver has the power of building up and storing certain +highly complex substances, derived from the food and brought to it +by the blood. The substances thus stored, and notably that known as +_glycogen_, are distributed to the body according to its needs, in +simplified and modified form. Now Wöhler in 1828 had synthetized urea +(p. 206) and it was well recognized that this substance is a final +degradation product which the body manufactures by breaking down the +substances derived from food. It was also recognized that from this +breaking-down process the bodily energy is obtained. Bernard showed +that the body could build up complex chemical substances as well as +break them down. This destroyed the conception, then still dominant, +that the body could be regarded as a bundle of organs, each with its +appropriate and separate functions. Bernard thus introduced what we may +call a ‘Physiological Synthesis’, a conception of great import for the +development of medical ideas. + +No less important, and bearing on the synthetic view of the working of +the animal body, was Bernard’s work on the physiology of digestion. +Up to the time of Bernard, an elementary knowledge of the facts of +digestion in the stomach constituted the whole of digestive physiology. +While Bernard was working on the glycogenic function of the liver, +another worker had suggested that the secretion of the organ known as +the ‘pancreas’, or sweetbread, emulsifies fats. Soon after, a German +researcher showed that pancreatic juice acts on starch. Bernard now +stepped in and cleared up the whole subject. He showed that digestion +in the stomach is, as he described it, ‘only a preparatory act’. He +proceeded to demonstrate that the pancreatic juice, passing into the +intestine, emulsifies the fatty food substances there and splits them +up into fatty acids and glycerin. He further demonstrated the power +of the pancreatic juice to convert starch into sugar, and he showed +that it has a solvent action on such ‘proteids’ or organic nitrogenous +substances as have not been dissolved in the stomach. + +The third great achievement of Bernard was his exposition of how the +blood-supply to the different parts of the body is regulated. This we +now call the ‘Vaso-Motor Mechanism’. In 1840 the existence of muscle +fibers in the coats of the smaller arteries was discovered. Bernard +showed that the contraction and expansion of the ‘arterioles’ is +associated with a complex nervous apparatus. The reactions of this +apparatus depend upon a variety of circumstances in a variety of other +organs; again an illustration of the close and complex interdependence +of the various functions of the body upon each other. + + +(c) _The Work of Karl Ludwig._ + +Karl Ludwig (1816-95) held a series of professorships at Marburg, +Zürich, Vienna and Leipzig. He was, after Müller, the greatest of +German physiological teachers, and he surpassed even Müller in the +number of his pupils. As a physiologist he was chiefly remarkable for +his ingenuity as an inventor, for his wide and deep knowledge of the +physical sciences and for his extreme generosity in handing over his +work to his pupils. + +Among the many lines of investigation of fundamental importance which +Ludwig initiated, some of the most remarkable depended on the discovery +of new methods. Just as the microscope had opened to the anatomist +unexplored fields of research by bringing him into closer relation with +objects which were hitherto beyond his scrutiny, so the rapid progress +of physics and chemistry had placed more exact modes of observation and +of measurement within reach of the physiologist. But the application +of these methods was attended with great difficulty; there was no +physiological laboratories, no instruments, no capable mechanicians +to whom the physiologist could apply for assistance. Under such +conditions, ingenuity and resource were indispensable to success, and +in these qualities Ludwig was pre-eminent. + +Accordingly, we find that two of the most important of the early +investigations of Ludwig were as much due to his ingenuity as an +inventor as to his clear grasp of the physiological questions which +his inventions were intended to elucidate. The most interesting of +these inventions, or rather adaptations, is the mechanically rotating +drum or _kymograph_, as it is called. The word itself is derived from +two Greek words which mean ‘wave writer’. This instrument is now +widely used, not only in Physiology but in every department of Science +in which permanent records of any continuous movement are desired. +The most familiar instance is the self-recording barometer. The +kymograph--the use of which had been suggested by Thomas Young (p. 319, +and Fig. 101) in 1807--led to much wider applications of the method of +automatic record. Ludwig himself applied it to indicate the movements +of respiration, as well as the variations in arterial pressure. +Subsequently it became further adapted to the ‘graphic method’, and +it serves not only for the investigation of animal movements of every +conceivable kind, but even for the transient and delicate electrical +changes which are associated with vital action. + +An instrument invented by Ludwig is the mercurial blood-pump, the +purpose of which is to separate from a known quantity of blood, derived +directly from the circulation, the mixture of gases which it yields to +a vacuum. This is an indispensable apparatus for the investigation of +the physiology of breathing. + +Ludwig devoted much attention to the physiology of secretion. Here his +work has been of great importance in connection with the time-honored +discussion between the ‘vitalists’ and the ‘mechanists’. He succeeded +in showing that the process of secretion can be so transformed +experimentally as to do external mechanical work. This was victory +for the mechanist theory. The idea has since been applied to many +structures. + +It is impossible to attempt here any general summary of the conclusions +reached by physiological research since Ludwig. Some have affected +the actual practice of Medicine. Others are too recent or too little +certain to have reacted in this manner. It is, however, safe to say +that the more important conclusions of the three modern founders of +the science, Müller, Bernard, and Ludwig, form the main scientific +background of the clinical practice of our time. The results of the +movement that they represent, together with the knowledge of the +cellular structure of the body (§ 5, p. 219) and of the life-histories +of the disease-causing organisms (§ 6, p. 224), are the three main +groups of ideas which separate the physician of our day from Laënnec +(p. 161). + +[Illustration: FIG. 101. THOMAS YOUNG’S KYMOGRAPH. + +The cylinder H turns with the axis AB on which it is rigidly fixed. It +is rotated by a handle at A which raises the weight C. When the weight +is allowed to fall the cylinder rotates automatically. The rest of the +apparatus is devised to secure constancy in rate of rotation. This was +done by utilizing the effects of centrifugal force. + +(As the rate of rotation increases the pendula D and E fly apart, they +separate the weights F and G. These move with friction which increases +as they separate, thus decreasing the rate of rotation.) + +The movements of the pen at K are transferred into permanent graphic +form by writing on the rotating cylinder H. + +] + + +§ 5. _The Cell Theory and Cellular Pathology._ + +During the process of the microscopic analysis of plants that took +place in the seventeenth century a number of observers distinguished +the walls of plant-cells and the word _cell_ was introduced into the +English language. Less clearly, a similar structure was discerned in +animals. No real understanding of the nature of cells was, however, +reached. Little farther progress was made in the eighteenth century, +but just at its close a young French microscopist, Marie François +Xavier Bichat (1771-1802), likened the microscopic structure of the +animal body to the substance of a woven fabric. The word he used was +the old French term _tissu_. He perceived that the different parts +of the body, bones, muscles, nerves, blood-vessels, and the like, +each presented a characteristic microscopic pattern. According to +these appearances he analyzed the parts of the body into twenty-one +‘tissues’. Study of this kind came to be called ‘Histology’ (Greek +_histos_ = web). + +During the seventeenth, eighteenth, and early nineteenth centuries, +some advances were made in the knowledge of those organisms whose +bodies are made up of only one cell, but their essential nature was +still unappreciated. In the early nineteenth century a number of +botanists and others were observing cells and cell contents. But no +important advance in the interpretation of the appearances was made +until the matter was taken up by Schleiden. + +Matthias Jakob Schleiden (1804-81), professor at Jena in 1838, put the +matter in a new light. He noted, as had certain of his predecessors, +the constant presence in every cell of the structure we now call the +‘nucleus’, and came to the conclusion that it is essential to the +life of every cell. He reached the conception, moreover, that in a +multi-cellular organism, such as a tree, every cell has a double life, +one an essential and independent one, pertaining to its own development +alone, the other an incidental and dependent one, in so far as it is +an integral part of the plant. His work was somewhat vitiated by a +fanciful conception of the origin of new cells. + +The work of Schleiden was amplified and corrected in 1839 by Theodor +Schwann (1810-82), a pupil of Müller. He showed that the tissues of +animals, like those of plants, are susceptible of analysis into cells, +and the difficulty of this process arises from the extreme modification +of such cells as have developed for various special purposes. He showed +too that the ovum or egg of animals is, in the first instance, a single +cell, and that the cells of the body are derived and descended from it. +He demonstrated that the entire animal or plant body is composed either +of cells or of substances that are excreted or thrown off by cells. +He gained some insight into the life of animal cells and in doing so +he invented the very useful word _metabolic_. The word means ‘liable +to change’. It was used by Schwann, and is still habitually used in +modern Medicine to indicate chemical changes within the body which are +specially associated with living activity. + +Contributions to the cell theory were made by other botanists. Hugo +von Mohl of Tübingen (1805-72) distinguished the contents of the +vegetable cell just under the cell-wall from the watery sap that fills +the interior, introducing for it the term _protoplasm_ (1846). The +Swiss, Karl v. Nägeli (1817-91), by chemical examination proved that +protoplasm is nitrogenous and differs from other cell constituents +(1862). + +The cell theory was placed on a firm and clear footing by Max Schultze +(1825-74), successor of Helmholtz (p. 213) as professor of Anatomy at +Bonn. He defined the cell as ‘a lump of nucleated protoplasm’ (1861), +introduced the idea of protoplasm as ‘the physical basis of life’, and +showed that it presented essential similarities, physiological and +structural, whether in plants or animals, and whether in higher or +lower forms. + +The study of tissues, Histology, was raised to the status of an +independent science by the Swiss, Albrecht von Kölliker (1817-1905), +pupil of Müller and professor at Würzburg, who wrote the first +text-book on the subject (1850-52). Apart from this achievement, +Kölliker is remarkable for having reached some of the conclusions in +connection with heredity that are associated with the name of Mendel, +of whose work he knew nothing. + +Even more influential on medical thought than Kölliker was Rudolf +Virchow (1821-1902) of Berlin, one of the leading names in modern +Medicine. There is indeed hardly any department of medical thought that +has not gained something from Virchow’s work. His great achievement +is the way in which he carried the Cell Theory into the analysis of +diseased tissues. In his _Cellular Pathology_ (1858) he analyzes +diseased tissues from the point of view of cell formation and cell +structure. Important sections of the science of Cellular Pathology have +been explored so well by Virchow that they have been little extended +by his successors. He initiated the familiar idea that the body may +be regarded as ‘a cell State in which every cell is a citizen’. +Disease is often but a civil war. The white blood corpuscles, which +have the power of engulfing and rendering innocuous bacteria and other +foreign bodies, have been compared to police or scavengers. In some +respects Virchow was strangely conservative, and notably he opposed the +evolutionary view of the origin of living forms. Virchow’s conceptions +of the functions of the white blood corpuscles were largely extended +by the Russian biologist Élie Metschnikoff (1845-1916) and the English +worker Almroth Wright (1861-). + +Since Virchow and Kölliker the study of the intimate structure and +workings of the cells themselves, as distinct from the tissues, +has become a separate and independent science under the name of +_Cytology_. It may even be extended to the study of cells in disease as +_Cyto-Pathology_. + +Among the major developments of Cellular Pathology and Cyto-Pathology +is the study of abnormal ‘new growths’. The most malignant types of +these belong to the group known as the ‘Cancers’. The occurrence of +most of these becomes more frequent as life advances (Fig. 135). Their +cytological features are now well known. A cancer consists essentially +of an increase of cellular tissue, following abnormally rapid +multiplication of one type of cell. The new growth is equipped with +a blood-supply which enables it to increase at the expense of other +tissues and regardless of their needs. + +Cancers almost always arise at one point, and are very seldom multiple +in origin. It is fairly established that they are not infectious or +contagious, and there is no very satisfactory evidence that a tendency +to them is inherited. Our scientific knowledge of Cancers is largely +derived from animals. Cancers are ‘specific’ in the sense that those of +one animal species will not grow when inoculated into another species. +An immense amount of work has been done on inoculated Cancers, but it +has become evident that some physiological factor is involved in Cancer +incidence such that an inoculated Cancer is not entirely comparable +with so-called ‘spontaneous’ Cancer. As to what that physiological +factor can be we are still in the dark. + +Although we know nothing effective as to this physiological factor, +yet experiments in the artificial production of Cancer, apart from +inoculation, have been attended with success. That various forms of +chronic irritation are associated with the onset of Cancer has long +been clinically recognized. It has been found possible to reproduce +experimentally this relation between irritation and new growth, and +so, for example, to induce Tar Cancer in mice. Nevertheless, it must +be admitted that Cancer investigation is in an unsatisfactory state, +and has yielded fewer positive results than any other department of +Pathology of comparable importance. It is possible that we do not yet +know enough of normal Cell Physiology to investigate with profit the +forms of cellular perversion known as Cancer. + +[Illustration: + +Drawings by Theodor Schwann to illustrate the nature and origin of +animal cells. All are highly magnified. + +FIG. 102. The first step in the origin of cartilage from cellular +tissues. At the lower part the young cells are without cell-walls. In +the upper part they have formed walls and are beginning to secrete +cartilaginous substance. Nuclei and nucleoli are clearly visible. + +Above is shown a piece of maturer cartilage, in which the cells are +imbedded in a mass of cartilaginous material. + +FIG. 103. Pigment cells, such as are characteristic of the skin of the +frog. In the lowest cell, which is contracted, the nucleus is concealed +by the pigment. The upper two are more expanded and in them nuclei can +be seen. + +FIGS. 104 & 105 show how structures of very diverse form can be +differentiated from cells of the same type. + +FIG. 104. Young cells from a developing feather. These cells may +enlarge, secrete hard walls, and form the fine spongy tissue of the +inner part of the shaft of the feather. Or the cells may elongate, the +protoplasm become granular, and finally break up into fibers (Fig. +105). These form the tough fibrous matter of the outer part of the +shaft of the feather. In either case, the nucleus disappears and the +cell dies. + +] + + +§ 6. _Establishment of the Doctrine of the Germ Origin of Disease._ + +The view that many diseases, especially those of a contagious or +infectious nature, originate from the invasion of the body by +special organisms and their multiplication within the body, came +into prominence in the second half of the nineteenth century. There +had been many previous adumbrations of this view and, in its final +establishment, more than one hand may be discerned. Above all others +who have worked in this field towers the mighty figure of Louis Pasteur +(1822-95). We shall do no grave injustice to any man if we treat the +scientific demonstration of the doctrine as the product of his superb +genius. + +The opening of Pasteur’s interest in disease can be seen in his work +on fermentation. At first he was faced with the opposition of Liebig. +According to that eminent chemist, fermentation was not the result of +vital activity but was a purely chemical change (p. 207). A ferment +he regarded as an unstable organic product, the character of which +determined the manner of decomposition of the medium in which it is +placed. Pasteur demonstrated that, as there is a specific alcoholic +ferment, so there is a specific milk-souring ferment. Any nitrogenous +matter present in a fluid containing it will serve as food for the +development of a ferment, but will not of itself induce fermentation. +Ferments have, he demonstrated, the power of reproduction. Pasteur +rapidly seized on the idea of the specificity of ferments. An +albuminous sugar solution can be converted into various products by the +addition of various ferments. According as one sows, so will one reap. +The milk-souring ferment, Pasteur concluded, is organized and living, +and its action is correlated to its development and organization. No +life, no ferment; no ferment, no fermentation. + +[Illustration: FIG. 106. ORGANISMS OF FERMENTATION HIGHLY MAGNIFIED +from Louis Pasteur’s _Studies on Beer_ of 1876. + +1. Bacillus of Turned Wine. 2. Ferment of Soured Milk. 3. Butyric +Ferment. 4. Ferment of Ropy Wine. 5. Ferment of Vinegar. 6. Amorphous +deposit. 7. Sarcinae. + +] + +During the next years Pasteur applied himself to a study of ferments +and notably of those which involve deterioration of wines and beers. +This led him to perceive that there is a great multiplicity and +variety of these organisms. Now it was an old and well-known view +that fermentation, putrefaction, and the infection of disease had much +in common. It was perfectly natural, therefore, for Pasteur to regard +the latter in the light of a vital process. A great difficulty was, +however, the demand that any such doctrine made on the germ-bearing +capacity of the air. Cities were not slow to avail themselves of this +weakness, and pointed out that, according to Pasteur, the air must +be one solid mass of germs! For the opponents of Pasteur the living +organisms found in the process of fermentation or decomposition were +the result, not the cause, of the process. These organisms were +regarded by them as spontaneously generated in the fermentation +process. Thus arose a discussion of the old theme of spontaneous +generation. + +By 1859--the year of publication of Darwin’s _Origin of +Species_--Pasteur was engaged in controversy as to the ‘Origin of +Life’. The discussion specially turned round what were then regarded as +the lowest forms of life, the Bacteria. Were they ever spontaneously +generated, or were they not? If a flask of broth, supposedly sterilized +by boiling, went ‘bad’ and organisms appeared in it, was it certain +that they had come from without, or could they have been spontaneously +generated by the broth itself? Life must begin somewhere. Then why +not here at this lowest stage? If this view be justifiable, Pasteur’s +doctrine of the nature of ferments must fall to the ground. + +Pasteur had thus before him the task of proving a universal negative--a +task impossible in Formal Logic. But Science is not Formal Logic. In +the end he clinched the matter by an exquisitely simple experiment +which must, at once, carry conviction. A flask with a long S-shaped +neck is filled with a putrescible fluid. It is heated to boiling, to +kill all organisms, and then left in the still air of a room. Air can +enter, but any floating germs that enter naturally fall on the floor +of the S-shaped neck of the flask. Months may go by without any change +in the liquid, but once the neck is severed, so that organisms can +enter freely from the air, fermentation sets in within a few hours, and +organisms can be detected in the liquid. Only living organisms from the +air can have caused the change. + +[Illustration: + +FIG. 107. PASTEUR’S CRUCIAL EXPERIMENT to prove that fermentation or +putrefaction is the result of the action of air-borne organisms. The +S-shaped flask contains a putrescible fluid such as meat broth. The +flask containing the broth is subjected to prolonged heating to destroy +all organisms. It is then left in position with the mouth open. Days, +weeks, months, even years, may pass without sign of putrefaction. No +organisms reach the broth, since any that enter the open mouth fall on +the floor of the neck and remain there. Sever the neck of the flask so +that organisms can fall from the air directly on to the surface of the +fluid and these multiply. In a few hours putrefaction sets in. This +is shown by the formation of a film or scum on the surface just below +the severed neck. Microscopically the broth is seen to be teeming with +organisms. + +] + +The first disease which Pasteur was able to demonstrate as causatively +related to a living organism was a condition that was devastating the +silk-worm industry of France. In 1866 he proved the contagiousness of +the disease, showed that it was due to a living organism, and followed +the organism through the life-history of moth, egg, worm, and chrysalis. + +In 1870 the Franco-Prussian war broke out. Pasteur now decided to make +investigations into the diseases of beer, his object being to improve +the French brews and to carry the war into the enemy’s camp by making +them equal to the German! He succeeded in isolating special organisms, +mostly yeasts, which produced defects in beer (Fig. 106). This work +naturally led to an enlargement of his views on the nature and action +of micro-organisms. + +About this time Pasteur was elected a member of the French Academy +of Medicine, a very unusual honor for one not a medical man. Lister +had already begun his teaching, based partly on the work of Pasteur, +and indeed his first important paper on antiseptic surgery had been +published in the very year of the Franco-Prussian war. On entering the +Academy Pasteur found himself faced by all kinds of ancient prejudices +and misconceptions in connection with his new doctrine, and especially +with his denial of spontaneous generation. Among his supporters was the +physiologist, Claude Bernard (p. 213). His work proceeded to more and +more triumphant issues. + +The first disease that affects man on which Pasteur was able to throw +light was Anthrax, in relation to which his work interdigitates with +that of Robert Koch and some other observers. Anthrax is a deadly +and highly contagious condition which commonly affects cattle, but +sometimes spreads to man. As early as 1855, a German observer had +noted microscopic rod-like objects in the blood of beasts dead of +the disease. In 1868 an older French contemporary of Pasteur had +shown that a bacillus is not simply the inseparable companion of the +disease, but also is its cause and its only constantly acting cause. At +this time the losses of cattle from Anthrax in France were enormous. +The character of the outbreaks had been studied and seemed wholly +unexplained by what was known of the bacillus. Farmers found that they +lost cattle in fields from which infected animals had been excluded for +months or even years. How was it to be explained? + +The explanation was, in fact, advanced in 1876 by the German observer, +Robert Koch of Berlin (1843-1910), whose work was now beginning. +He showed that the anthrax bacilli under certain conditions formed +‘spores’, that is to say small encysted bodies, exceedingly resistant +to heat and to other changes of external conditions (Fig. 108). This +discovery opened up a new field which was cultivated by Koch and +Pasteur and their followers. + +[Illustration: FIG. 108. BACILLI OF ANTHRAX, from a culture, highly +magnified. + + The rod-like organisms are growing typically in chains. Some of + the rods have white clear spots in them. These are the highly + resistant ‘spores’. +] + +While making his studies on ferments in 1863, Pasteur had witnessed the +formation of spores in the organisms of butyric fermentation, but had +failed to grasp their significance. In 1869 he had again found spores +forming in the organisms of silk-worm disease, and had shown that they +resisted prolonged drying. On the basis of their resistance he had +explained the persistence and latency of the silk-worm disease. Other +observers had had similar experiences. The investigations of none of +them, however, approached in brilliance and completeness those of Koch. + +Koch found that spores always form in the blood and tissues of animals +dead of Anthrax, provided that + +(1) the temperature is suitable, and (2) there is sufficient +oxygen. These two conditions, temperature and oxygen, were found to +be necessary. Below 18° Centigrade spores are not formed; at 30° +Centigrade they occur at the end of thirty hours; at 35° Centigrade +in twenty hours. The rapidity with which spores are formed is, +therefore, proportional to the amount of heat. Oxygen was also found +to be indispensable. Anthrax blood, if deprived of oxygen, ceases to +be virulent in twenty-four hours without putrefaction. When the blood +is allowed to putrefy the virulence also disappears if putrefaction +exhausts the oxygen quickly enough to prevent the spores having time to +form. If the spores have already formed, putrefaction does not kill +them, nor does it prevent them from developing later if circumstances +become favorable. The persistence of the disease and its return in +an infected country was thus explained. It was the spore which was +the agent of preservation, which persisted where the conditions of +temperature and of aeration had permitted it to form, and which always +held itself in readiness to make new victims. + +The matter was carried further by Pasteur in 1877. At that time he +did not know of all the work of Koch. He succeeded in obtaining pure +cultures of Anthrax. The question was then still being debated in +France as to whether Anthrax was caused by a ‘virus’, that is to say a +non-living poison, or by a microbe. Pasteur had long been a believer in +the microbic theory, and it seemed to him probable that the blood of an +animal infected with Anthrax, if sown in a suitable medium, would stock +it solely with anthrax bacilli which he could then keep pure for an +indefinite time in successive cultures, as he had done with yeast and +other ferments. + +Experiment proved this to be the case, and showed that the anthrax +organism multiplied abundantly in urine made neutral or slightly +alkaline. From that time the problem was solved. Take a series of +cultures of the organism, transferring each time one drop from the +preceding culture into 50 c.c. of fresh urine. The first dilution +is 1/1000, the second one in a million, the third one in a thousand +million. After ten cultures it falls to such a figure that the +original drop of blood has been drowned in an ocean. Everything that +it carried with it, to which we might attribute the production of +Anthrax--red corpuscles, white corpuscles, granules of all sorts--is +either destroyed by the change of medium or is widely disseminated in +this ocean and is lost. Only the organism can escape the dilution. Why? +Because it has multiplied in each of the cultures. A drop from the last +culture killed a rabbit or guinea-pig as surely as a drop of anthrax +blood. It was, therefore, to the organism that the virulence belonged. +A conclusion of the first rank was firmly established. + +With a ‘pure culture’ of Anthrax in his possession Pasteur was able +to experiment in a way which none had previously attempted. The most +interesting stage of his work was now entered upon. He perceived that +there are some species of animals which are refractory to Anthrax. +Such are the birds. Nevertheless, the blood of a bird, when drawn +from the animal, is an excellent culture medium for the bacterium. +Why does it resist infection in the animal? Pasteur showed that the +anthrax organism will not live in the bird because the living-blood +in full circulation is filled with an infinite number of corpuscles +which, in order to live and perform their physiological function, need +free oxygen. When, therefore, the anthrax organism enters normal blood +of living birds, it meets competitors ready to seize the oxygen for +their own use. But the blood of other animals besides birds contains +corpuscles eager for oxygen. Why can anthrax grow in them and not +in birds? This question Pasteur answered by a convincing series of +experiments (1878). The normal temperature of birds is higher than that +of mammals and is, moreover, higher than that at which the growth of +the anthrax organism is most vigorous. Thus the blood corpuscles of +the bird have the anthrax bacteria at a disadvantage. But if, by a cold +bath, the temperature of a bird be lowered to that of a mammal, and if +anthrax organisms be injected into the blood-stream, they will grow and +flourish at the expense of the bird. + +The experiments with Anthrax on fowls led to experiments on the same +creatures with another disease, the virulence of which was known +to vary, Chicken Cholera. Thus arose naturally Pasteur’s ideas and +observations in the department of Immunity (p. 261). + +If Pasteur can be said to have laid the foundations of the knowledge +of the nature of infection, it is to Koch that we owe the main basis +of the technique by which diseases are now studied. He it was who +elevated Bacteriology into the position of a separate science. Soon +after his work on Anthrax he published a remarkable research which +placed our knowledge of wound infection on a firm footing. He is thus +among those who helped to create modern surgical technique. Many other +communications came from him. None was of more far-reaching importance +than his demonstration of the organism of Tuberculosis in 1882. All +subsequent work in connection with Consumption and allied conditions +has been rendered possible only by this discovery of Koch. Other +investigations associated with his name are on Cholera and on Sleeping +Sickness. Koch was unquestionably the greatest bacteriologist that the +world has seen. His genius was limited as compared to that of Pasteur, +but his exquisite technical skill and acumen have never been excelled. + +Since the time of Pasteur and Koch, the study of infectious disease +has developed along various special lines. The work of these two +men, however, has determined the direction of those lines, and +they themselves are the most typical, as well as the greatest, +representatives of the most important of all movements in modern +Medicine. + + +§ 7. _Anaesthesia._ + +The aspect of surgical practice was dramatically changed during +the course of the nineteenth century by two discoveries, that of +Anaesthesia and that of the Antiseptic method. It will be convenient to +consider Anaesthesia first. + +There were from the earliest times many devices for producing more +or less complete unconsciousness during surgical operations. An idea +of the extremes to which surgeons at the beginning of the nineteenth +century were put in this matter can be gathered from a glance at some +of their devices (Fig. 108a). + +The new era began in 1846 when the dentist, William Thomas Green Morton +(1819-68), demonstrated at the Massachusetts General Hospital the +simplicity and safety of Ether anaesthesia. The idea immediately caught +on. Before the year was out Ether was being used for surgical purposes +in England. In January, 1847, Sir James Young Simpson (1811-70) was +using it in Edinburgh for obstetric purposes. A few months later he +adopted Chloroform, which had been prepared by Liebig in 1832. + +The use of the drugs spread very rapidly and almost as rapidly changed +the character of surgical technique. Until the adoption of anaesthesia, +speed was of primary importance in surgical procedure. Excessive speed +now became a matter of less importance, and operative neatness and +completeness took its place as the chief quality of good surgery. +Moreover, operations of a more drastic character could be undertaken +since the shock to the patient was minimized. Women in labor were found +to bear Chloroform peculiarly well and safely, and its use in midwifery +steadily spread despite some foolish and fanatical opposition. + +Soon after the introduction of anaesthetics efforts were made by +various methods to secure a painless state of a part without involving +unconsciousness. The first successes were obtained in 1884 at Vienna +with applications of solutions of the alkaloid (p. 325) Cocaine, +first to the eye, then to the nose and other parts. Cocaine, or some +derivative of it, has ever since been much used in Medicine. It was +soon being given by injection under the skin for small superficial +operations. Next, good results from injecting solutions of it into the +nerves were obtained by several American surgeons, earliest of whom +was W. S. Halsted (1852-). His work of 1885 was extended in 1898 by +Harvey Cushing (1869-). Yet another American surgeon, J. L. Corning +(1855-), introduced the method of so-called ‘spinal anaesthesia’. +This is secured by injecting a solution of Cocaine or one of its +derivatives into the spinal canal and thereby inducing insensibility to +pain (‘analgesia’) below the site of injection. In 1908 the American G. +W. Crile (1864-) introduced a valuable method of combining local and +general anaesthesia, whereby he minimized the effects of ‘shock’ (pp. +310-11) during the progress of the operation. + +From first to last almost all the pioneer work upon anaesthetics and +analgesics has been of American origin. Even the word _anaesthesia_ +is an American invention. It was introduced or at least familiarized +by Oliver Wendell Holmes (1809-94), the distinguished and brilliant +author of the ‘Breakfast Table’ series. Laughing Gas was first applied +to dental purposes a short time before Ether was given its surgical +application, and its introduction for this purpose was the work of the +American dentist Horace Wells (1815-45), of Hartford, Connecticut. + +[Illustration: + +FIG. 108a. SCREW adapted to the lower limb, as used by surgeons in the +eighteenth century and the early nineteenth century, to compress the +nerves in order to secure analgesia during amputation. Its application, +however, was extremely painful in itself and injurious to the part +operated on. + +] + + +§ 8. _The Revolution in Surgery._ + +This history of antiseptic surgery is inseparably linked with the name +of Lord Lister (1827-1912), whose work naturally dovetails into that of +Pasteur. Lister’s attention was first called to the work of Pasteur in +1865. But Pasteur’s views on the life of micro-organisms came to a mind +that had been prepared for them. Lister had had, moreover, a long and +varied surgical experience and had been present at the first operation +performed in England under Ether anaesthesia in 1846. + +At that time and for long after, Surgery was cursed by the constant +fear of sepsis. A vast amount of death and suffering was due to this +cause, and surgeons were reluctant to perform many operations that +we should now regard as trivial. Lister’s first attempt to make any +scientific analysis of the septic state is to be found in a paper by +him on _The Early Stages of Inflammation_ (1853). He showed that the +effects of irritation on the tissues are twofold. Firstly, there is +a dilatation of the arteries which is developed through the nervous +system. Secondly, there is an alteration in the tissues on which the +irritant acts directly. This alteration imparted, as Lister thought, +an adhesiveness to both the red and the white corpuscles, making them +prone to stick to one another and to the walls of the vessels, and so +giving rise to stagnation of blood and ultimately to obstruction. + +Some years before (1847) A. V. Waller (1816-1870), a pupil of Magendie, +had shown that during the process of inflammation there is an active +migration of white blood corpuscles through the walls of the capillary +blood-vessels. Waller’s observations attracted but little attention at +the time. They were, however, amply confirmed in 1878 and the following +years by the German pathologist Julius Cohnheim (1839-84), a pupil of +Virchow. Cohnheim showed that this process of migration of white blood +corpuscles is the essence of inflammation and that when inflammation +goes on to suppuration the pus that is formed consists largely of white +blood corpuscles in a dead and disintegrating state. + +Irritation, and the reaction of the body against it, ‘inflammation’, +are encountered in all injuries in which the healing is not direct +and healthy. It was those cases of injury in which the healing was +indirect and unhealthy which then formed the surgeon’s chief problem. +Of these there are a variety, now rare, then very common and fatal, +as Blood-Poisoning, Erysipelas, Pyaemia, Septicaemia, Hospital +Gangrene, and that form, then so common as to be almost normal, simple +suppuration of a wound. + +About 1861 Lister began to teach publicly that the occurrence of +suppuration in a wound is determined ‘simply by the influence of +decomposition’. The nature of decomposition was revealed to him by the +writings of Pasteur. From him he learned that putrefaction was, in +fact, a fermentation, and that it was caused by the growth of minute +microscopic organisms borne by the air. It was generally supposed that +air was the cause of sepsis, and precautions were taken to exclude it +from wounds. But Lister now saw that not air but that which it carried +was the mischief-maker. + +The general course of action was now clear to him. As a laboratory +proposition the destruction of the organisms of the air was simple. The +problem was to exclude them from wounds during and after operation. The +solution of that problem developed as ‘Antiseptic Surgery’, which later +became ‘Aseptic Surgery’. At first he paid most attention to air, as +the source of infection. He recognized, however, that he must also deal +with the germs present in the wound and on his hands. Of the methods +available for ridding the air of its germs, viz. heat, filtration, and +chemical action, he chose the last. + +At that time carbolic acid was in use as a means of treating sewage. At +first, therefore, Lister tried lint soaked in crude carbolic. This he +found liable to cause superficial sloughing and death of the tissues. +He next obtained a purer acid, using a solution in oil. A putty formed +of common whitening and a solution of carbolic acid in linseed oil was +used as a dressing. He adopted later a system of spraying the part +during operation (Fig. 109). + +[Illustration: + +FIG. 109. THE ‘DONKEY ENGINE’, an apparatus designed and used by Lord +Lister to maintain a carbolic spray over a part during operation. The +engine is worked by the up and down movement of the handle to the right +and the spray is delivered through the tube to the left. + +] + +When Lister began his work, amputation of a limb was a very fatal +operation. Yet it had to be performed in most cases of severe fracture +in which the bone was exposed because, without it, death from sepsis +was almost certain. The improvement in Lister’s own records of +amputation, incident upon his adoption of the antiseptic method, is +well brought out by his own figures: + + _Years._ _Cases._ _Recovered._ _Died._ _Mortality._ + 1864-66 35 19 16 43% without antiseptics + 1867-70 40 34 6 15% with antiseptics + +These results were considered extraordinarily good in their day. It +is an index of the further advance since Lister’s first attempts that +results ten times as good would now be regarded as unsatisfactory. +Moreover not only has the further development of Lister’s method +rendered amputation safer, but also it has enabled the surgeon to treat +many cases without amputation, when before he would have been compelled +to resort to that measure. + +Lister first recorded his observations on the antiseptic system of +surgery in 1867. Apart from the technical advances that he then set +forth, he recorded also many new pathological facts that have since +proved of great practical importance. Thus he showed that an uninfected +clot, if undisturbed, can become organized into a living tissue, and +that a piece of dead bone may be absorbed in an aseptic wound. These +are now matters of common knowledge, but then they were instrumental +in introducing a radically new outlook. + +Lister gradually perfected his technique, chiefly in the direction of +using milder antiseptics and adopting heat for the sterilization of +instruments and dressings. The antiseptic system was given its military +application in France during the war of 1870. It was soon taken up also +by German surgeons. The history of surgery since Lister’s day has been +very often told. An important element in it is the gradual supersession +of ‘antiseptic’ by ‘aseptic’ methods (p. 248). + +The Listerian system, in rendering surgery safer, had also the +effect of opening up many fields of operation that had previously +been regarded as impracticable. Especially is this the case with +abdominal surgery, which effectively dates from the introduction of +the antiseptic system. Lister was often misunderstood and some of his +contemporaries, and some even of those who opposed him, were really +practising his system without knowing it. + +Among the most important reactions of antiseptic surgery was that upon +the conduct of labor. Here Lister had a predecessor, as he gladly and +generously acknowledged. This was the unfortunate and almost insane +Viennese genius, Ignaz Semmelweis (1818-65). At the great lying-in +hospital at Vienna in which he was an assistant the death-rate at one +time rose to thirty per cent., the so-called ‘puerperal fever’ being +the active cause. The women were attended by students or physicians +who were visiting the post-mortem room. Semmelweis showed that the +infective material that conveyed the fever was brought by the hands of +the operator from the dead bodies and he showed that puerperal fever +was caused by decomposed animal matter. By insisting on the hands +of the operators being sterilized, Semmelweis succeeded in 1846 in +enormously reducing the mortality. After the acceptance of Lister’s +antiseptic system the methods of Semmelweis were universally introduced +into the practice of Midwifery. Another predecessor of Lister was +Oliver Wendell Holmes. As early as 1843 he pointed out that the +mysterious ‘puerperal fever’ was contagious, and carried by the hands +of the operator. He suggested precautions not dissimilar to those of +Semmelweis. + +[Illustration: FIG. 109A. OPERATING TABLE USED BY LORD LISTER in the +Glasgow Royal Infirmary.] + + +§ 9. _Some Modern Surgical Advances._ + +Among the most capable surgeons of Lister’s own day was Thomas Spencer +Wells (1818-97) of London. This great operator had been opening the +abdomen successfully for certain conditions since 1858. By 1867 his +methods were approaching the Listerian. Under Lister’s inspiration +he further improved his technique and did more than any other man to +raise the possibilities of abdominal surgery. Spencer Wells stands +out for the extreme simplicity, directness, and effectiveness of +his methods (Fig. 111), and for his exceptionally conscientious care +as an operator. His name is commonly attached to an instrument of +his invention of catching the bleeding ends of cut blood-vessels. +The familiar ‘Spencer Wells forceps’ is at this day probably more +frequently used than any other surgical instrument (Fig. 110). + +[Illustration: FIG. 110. ‘SPENCER WELLS FORCEPS.’] + +[Illustration: + +FIG. 111. SPENCER WELLS performing an abdominal operation about 1870. +The picture illustrates the extreme simplicity of the methods of this +great surgeon. It also shows a method of administering chloroform. Air +is pumped through a bottle into a mask held at a variable distance from +the face of the patient. + +] + +Since the time of Lister many branches of Science have contributed to +the development of surgical technique. No addition to the surgical +armory has, however, been more important than that made by the +physicist Wilhelm Conrad Röntgen (1845-1923). In 1895 he found that +when an electric discharge passes through a high vacuum rays are +emitted that are far more penetrating than ordinary light. These rays +have since then been placed in series with light rays, ultra-violet +rays and infra-red rays, and it has been shown that they differ from +these only in their wave-length. The surgical application of the +Röntgen or X-rays was at once made to the examination of bone. Since +then the more accurate knowledge of the properties of these rays +has made them of value in exploring almost every organ of the body. +Radiography is now constantly applied in the diagnosis of medical and +surgical conditions of the organs of the chest and abdomen. + +The more dramatic achievements of modern surgery, the drastic +operations that surgeons are now able to perform on the great cavities +of the body--head, chest, and abdomen--have attracted much public +attention. Nevertheless few surgical advances have relieved so much +suffering and disability as the unsensational development in the +treatment of fractures. + +After the advent of Listerian methods the technique of the treatment +of compound fractures was gradually perfected. Simple fractures--which +are far commoner--continued, however, to be treated with splints in +the traditional fashion. Plaster of Paris bandages, which came into +wide use in the ’seventies, were some improvement; but prolonged +immobilization of a limb, in either splints or plaster bandages, always +involves much subsequent pain and stiffness, lasting, at best, for +months. To obviate this, Massage--a practice of immemorial antiquity +in Folk Medicine--had been introduced into Surgery in the sixteenth +century by Ambroise Paré (pp. 92-94). The subject was little heard +of till the last thirty years of the nineteenth century. The pioneer +was the Dutch surgeon Johann Mezger (1839-1900), through whom some +scientific advance was made. + +[Illustration: FIG. 112. AN OPERATION IN THE SIXTEENTH CENTURY. + +The semi-conscious patient lies face downward on an elaborately +carved bed. The bearded surgeon, dressed in his ordinary clothes, is +trephining his skull and is rotating the trephine between his hands. +Against the side of the bed lounges a gallant to whom a servant brings +refreshment. In the background are two women assistants. A male +assistant is spreading a plaster and another warming a towel over a +brazier. Note that all present, surgeon, nurses, assistants, &c., wear +their ordinary dress. No arrangements are made for washing. In the +foreground is a cat playing with a mouse. ] + +The introduction of X-rays into Surgery made for very accurate +diagnosis of the state of fractures. It has thus gradually become +possible to treat a large proportion of these injuries without +immobilization either by splints or plaster. In many cases the injured +limb is merely held in correct position between sandbags and massage +used from the first. Much stiffness and disability is thereby avoided +and the length of the period of treatment greatly shortened. The rise +of a class of scientifically trained Masseurs has made possible a wider +application of this valuable curative procedure. + +Improvements in methods of operation have been very numerous during +the last generation. Many can be appreciated only by those with +technical knowledge. In 1886 Ernst von Bergmann of Berlin (1836-1907) +introduced steam sterilization of dressings and thus moved toward the +replacement of antiseptic by aseptic methods. W. S. Halsted, then +of New York, had been working to the same end. In 1890, finding it +impossible to sterilize the hands completely, he introduced the rubber +gloves now universally employed by surgeons during operations. Much +important work in experimental surgery has been done by Alexis Carrel +of New York (1873-) and some of his laboratory methods have become +available in surgical practice. The technique of abdominal surgery has +been greatly advanced by many workers, important among whom are J. B. +Murphy (1857-1916) of Chicago and the brothers Charles and William Mayo +(1865 and 1861) of Rochester, Minnesota. The surgery of the brain was +prosecuted in England by Rickman Godlee (1849-1925), the nephew and +biographer of Lister, by Victor Horsley (1857-1916), and above all by +William Macewen (1848-1926), a successor to Lister’s chair at Glasgow +and one of the finest exponents of Listerian methods. The surgery of +the nervous system in general, and that of the brain in particular, has +been carried to extraordinary refinements in America by Harvey Cushing. +There can be no doubt that during the twentieth century advances in +Surgery have been more important and more numerous in the United States +than in any other country. + +[Illustration: FIG. 113. AN ABDOMINAL OPERATION UNDER MODERN CONDITIONS + +Only those directly concerned with the operation are present in the +room. All wear aseptic clothes and aseptic rubber gloves. Every source +of infection is guarded against and all breathe through masks. The +patient is covered by aseptic cloths and only the part operated on is +exposed. + +] + + +§ 10. _Bacteriology becomes a special Science._ + +We have seen the microbic view of the origin of disease demonstrated +as a reality by Pasteur (pp. 224-35) and extended to special disease +conditions by him and by Koch (pp. 229-32). While the French observer +stood above all men for the clearness and steadiness of his vision and +for his persistence and resource in following what he had seen from +afar, his German colleague had a genius for visualizing particulars +and for adapting mechanical devices and scientific discoveries to +particular ends. Koch thus vastly improved and elaborated the methods +for detecting and examining minute organisms. The significance of his +results was at once recognized, but the complexity of the technique +involved and the time and training necessary demanded the elevation of +the subject into the position of a special science. + +Though but fifty years old, the science of Bacteriology has itself +undergone repeated subdivision. Noteworthy though the results of this +process of constant subdivision have proved, it must be emphasized +that the state of scientific subdivision cannot be final, and is +indeed without meaning unless it lead to a subsequent synthesis--an +event which we still await. It is the general Laws reached by these +special sciences that are philosophically important, and the specialist +himself is often ill-placed and ill-equipped for the estimation of the +true significance of such Laws. The philosophic thinker who deals with +generalities and centuries must often be content to pass the details in +silence. Nor is this true only of the professed philosopher. It applies +no less to the philosophical physician. It is his task to try to see +life steadily and see it whole. He must think both in terms of the +individual life and of the community life, and for him the results of +the bacteriologist, the physiologist, and of all their colleagues are +as means to an end. It is from this standpoint that we should seek to +visualize the fruits that bacteriological science in this last age has +laid at the feet of humanity. + +With Koch’s work on Anthrax in 1876, on the bacteria that commonly +infect wounds in 1878, and with his great discovery of the bacillus +of Tuberculosis in 1882, the study of the infective diseases entered +on a new stage. The enemy had been seen and was now known for what he +was. The bacteriologist had succeeded in making prisoners. These had +been isolated and made to live in test-tubes. Moreover, the organisms +had been compelled to dwell alone without mixing with other species. +They had been obtained, as bacteriologists say, in ‘pure cultures’, +and delicate methods of detecting and differentiating them had been +developed. With a pure culture in his hands, the bacteriologist can +determine the influences favorable or unfavorable to the growth of the +disease organism, and he can investigate conditions that can exalt, +destroy, or modify its activity (p. 233). + +An important series of criteria established by Koch have remained the +tests by which the disease-bearing character of these organisms can be +established. To prove that an organism is the inseparable cause of any +disease we need to demonstrate: + +1. The constant presence of the organism in every case of the disease. + +2. The preparation of a pure culture, which must be maintained for +repeated generations. + +3. The reproduction of the disease in animals by means of a pure +culture removed by several generations from the organisms first +obtained. + +These conditions have been fulfilled for many diseases. Evidently the +third test can be applied only in conditions to which animals other +than man are susceptible. Now in this matter the organisms that produce +disease vary greatly. Some, for instance those of Anthrax, are easily +conveyed to a variety of species of animals; others, for instance +those of Syphilis, are with difficulty conveyed to very few species of +animal; yet others, for instance human Malaria, cannot be conveyed to +any animal save man. + +Some light is thrown on the life-history of the second and third +classes by recent discoveries. The science of Comparative Pathology, +that is the knowledge of the relations of the diseases of different +species of animals, is of very recent growth. It has already +demonstrated, however, the existence of organisms bearing some +resemblance, for instance, to those of human Syphilis and human Malaria +as the cause of disease in animals. By studying the life-history of +these organisms in animals and by studying their effect on animals, +valuable side-lights have often been thrown on the allied diseases in +man. Moreover, in exceptional cases and in some special diseases, it +has been possible to convey a disease experimentally to man. + +A second important factor has gradually come into prominence with the +extension of bacteriological knowledge. It is evident that not all +men are subject to all human diseases. Even in the most destructive +epidemic there are some that escape. These lucky ones may be naturally +‘immune’. Many diseases, such as Measles, seldom recur in individuals +who have been infected, so our lucky ones may thus have an ‘Acquired +Immunity’. + +The general nature of Immunity we shall presently discuss (p. 259), +but we note here that Immunity may be relative or absolute, and may, +moreover, vary according to the circumstances of the individual. Thus, +for instance, a well-fed, well-housed person of temperate habits, +living an open-air life, is unlikely to develop consumption. Restrict +his diet, confine him in an office, deteriorate his mode of life, +and he may well fall a victim to it. The investigation of facts such +as these on a large scale has demonstrated that the _soil_ in which +disease grows is of no less import than the _seed_ from which it grows. +The problem of disease causation is thus immensely complex. We are +only just beginning to draw up general laws on the subject, and in +approaching it we are beyond the frontiers of our positive knowledge. +Turned back from this difficult borderland, we must content ourselves +with surveying a part of the better-known territory and considering a +few specific bacteriological achievements. These we may now consider +under the headings of the diseases associated with them. + + +§ 11. _Some Important Bacteriological Results._ + +_Diphtheria_ is a disease for which physicians now habitually demand +a bacteriological diagnosis. Bretonneau of Tours (p. 185), working on +clinical and post-mortem material, and without the use of a microscope, +was able to distinguish Diphtheria as a specific disease (1826). Half +a century later (1883) Edwin Klebs (1834-1913) of Zürich, a pupil +of Virchow, described the specific organism of the disease. In the +following year Friedrich Loeffler (1852-1915), a Prussian and an +assistant of Koch, succeeded in cultivating it. The organism has since +been known as the ‘Klebs-Loeffler Bacillus’. Its study has thrown much +light on the nature of bacterial action in general and has, moreover, +led to important therapeutic developments (p. 263). + +Of all diseases destructive of human life, none is so dramatic as +_Plague_, the scourge of mankind throughout history. The bacillus +of Plague was discovered independently by the Japanese Shibasaburo +Kitasato (_c._ 1860-), a pupil of Koch, and by the Frenchman Alexandre +Yersin (1863-), a pupil of Pasteur, during an epidemic at Hong Kong +in 1894. These two observers cultivated the organism and reproduced +the disease by inoculation of pure cultures in animals. It had long +been observed that outbreaks of a deadly disease of rats and mice +were liable to precede Human Plague. These ‘epizootics’ which precede +‘epidemics’ are now known to be due to the bacillus of Plague. A mass +of evidence has been collected to show that the normal carrier of +the Plague infection is the rat flea. This knowledge has led to the +formulation of effective measures for the control of Plague. These +measures are based on the wholesale extermination of the rat population +which harbors the infective fleas. The study of the Natural History +of the Plague Bacillus has also led to prophylactic measures for the +safety of individuals. + +[Illustration: + +FIG. 114. BACILLI OF DIPHTHERIA FROM A CULTURE. Highly magnified. In +cultures these bacilli are liable to degenerate into thick club-shaped +forms several of which are here seen. + +] + +[Illustration: FIG. 115. BACILLI OF PLAGUE FROM A CULTURE. Highly +magnified.] + +_Malta Fever_ is a disease of much wider distribution than its name +implies. Not only is it found throughout the Mediterranean area, but +it is also encountered in China, South Africa, and parts of both North +and South America. It is a long, tedious and wearing disease, and +though the mortality from it is low, yet it was at one time one of the +main causes of disability in the British army at Malta. In 1887 an +English military surgeon, David Bruce (1855-), succeeded in cultivating +a characteristic bacillus from the spleen of a patient dead of the +disease, and he established its causal relation to Malta Fever. In 1904 +its mode of propagation was studied by a British Government Commission. +The goat was shown to be the normal host of the bacillus, and in Malta +50 per cent. of these animals were found to be infected. The disease, +it was discovered, is usually transmitted by goat’s milk. The knowledge +has led to the application of very effective precautions (Fig. 116). + +[Illustration: + +FIG. 116. DIAGRAM SHOWING THE INCIDENCE OF MALTA FEVER in the British +garrison at Malta immediately before and immediately after the +institution of the preventive measure of cutting off the supply of +unboiled goats’ milk. The figures of 1905--before the new regulation +came into force--are represented in black. The figures in the margin +refer to the number of cases per ten thousand of strength. The figures +for 1907 are represented in white on the same scale. There is a drop in +the maximum monthly incidence from 94 to 2. The size of the garrison +itself remained almost constant throughout the period. ] + +Among the most anciently described diseases is the condition known as +_Tetanus_ or ‘Lockjaw’. There are unmistakable references to it in the +_Hippocratic Collection_ and notably in the _Aphorisms_. Two of these + +references we have already quoted (p. 23). A general association +of Tetanus with wounds has long been recognized. In the eighties +the disease was shown to be transmissible from animal to animal. It +was, moreover, experimentally produced in animals by the inoculation +into them of garden mold. In 1889 Koch’s pupil, Kitasato, obtained +the Bacillus of Tetanus in pure culture and conveyed the disease to +animals. He found the organism would grow only in the absence of +Oxygen. It is, in fact, a type of a large and now well-known group, +the ‘anaerobic’ bacteria. The natural habitat of the Tetanus Bacillus +has been proved to be soil, and especially richly manured soil. The +knowledge of the bacillus, of its habitat, and of its mode of growth +has led to the development of a valuable protective process. + +Looking backward from the standpoint of present-day knowledge we can +trace _Typhoid Fever_ far back in history. Nevertheless, it was not +till 1837 that the distinction between the two distinct conditions +known now as ‘Typhoid’ and ‘Typhus’ was first clearly made. This was +the work of an American physician, William Gerhard (1809-72), of +Philadelphia. The English were backward in adopting the distinction. +The organic cause of Typhoid Fever was first seen in 1880 by Karl +Joseph Eberth (1835-1927), a pupil of Virchow, and after him it is +known as ‘Eberth’s Bacillus’. It was not isolated, however, until some +years later. It is an inhabitant of the intestine, and its natural +history was obscured by confusion with certain other and very similar +organisms, which also dwell in the intestine. These have now been +fairly differentiated from each other, and in the course of this +process the ‘flora’, both normal and pathological, of the intestinal +canal has become well known. Moreover, it has been shown that typhoid +organisms are not always of the same species, but that several +closely allied forms produce several closely allied diseases. Lastly, +certain of the effects wrought by the typhoid group of organisms on +the body, which is their host, have been exactly investigated. These +investigations have led to improved methods of recognition of the +disease, that is to say, _diagnosis_, and also of prevention of its +incidence, that is to say, _prophylaxis_. To these methods of diagnosis +and of prophylaxis we now turn. + +[Illustration: + +FIG. 117. BACILLI OF TETANUS FROM A CULTURE. Highly magnified. The +drum-stick forms are very typical. + +] + +[Illustration: + +FIG. 118. BACILLI OF TYPHOID FEVER FROM A CULTURE. Highly magnified. +The long flagellae, which are constantly in motion and are very +characteristic of these organisms, are well seen. ] + + +§ 12. _The Study of Immunity._ + +In the production of disease by living organisms two main factors +are involved. There is, firstly, the multiplication of the organisms +themselves, and there is, secondly, the production by the organisms +of poisonous substances or _toxins_. The former phenomena are spoken +of as _infection_, the results of the latter come under the title of +_intoxication_ or _toxic_ effects. The first toxins to be investigated +were those isolated from putrefying substance and named _ptomaines_ +(1876, by false formation from Greek _ptoma_ ‘a corpse’). These are, in +fact, definite chemical substances of the group known to chemists as +‘alkaloids’ (p. 325). Later, toxins were prepared from actual disease +organisms such as those of Typhoid and Tetanus (1888). The method was +introduced of filtering the bacteria away from their fluid cultures +and thus obtaining a bacterium-free liquid containing the poisonous +bacterial products. This was the starting point of the scientific +study of toxins. These, it soon became clear, were either substances +which were normally sent out by the bacteria, _exotoxins_, or they +were normally retained within the bacteria and could only be obtained +in solution by breaking up the bodies of the bacteria, _endotoxins_. +The use of these toxins has been essential for the scientific study of +Immunity. + +The word _Immunity_ is derived from a Latin word which means ‘exemption +from military service’. In Medicine it indicates an exemption, relative +or absolute, from the incidence of a disease. Immunity in the medical +sense is of various kinds. There is ‘species immunity’, some species +not being liable to diseases to which others fall victims. There is +relative and there is absolute immunity. There is innate and acquired +immunity. Of acquired immunity there is a natural immunity resulting +from the ordinary contraction of a disease, and there is an ‘artificial +immunity’. It is only artificial immunity that is in the hands of the +physician. + +Artificial immunity itself is of two kinds, and both kinds are of use +and of importance in Medicine. There is an _Active Immunity_, which is +produced directly by injection of disease organisms or their products. +It is found, however, that if a high degree of active immunity be +attained the blood serum of the immunized animal, when injected into a +second animal, may itself produce a state of immunity. The state thus +indirectly produced is described as _Passive Immunity_. + +The early observers found that when organisms are cultivated outside +the body they lose their virulence to a greater or less degree. Pasteur +found this for Chicken Cholera (p. 234). He found, moreover, that such +‘attenuated cultures’, when inoculated, protect against the disease. +By the use of attenuated cultures he succeeded in establishing a state +of ‘Active Immunity’ against Chicken Cholera. But there are many other +ways of attenuating the virulence of an organism. Thus, in 1882, +Pasteur showed that to grow Anthrax bacilli at a high temperature would +reduce their virulence. These bacilli of reduced virulence could be +injected into a sheep. They would give the animal the disease in a mild +form and protect it against further attacks of the disease. They acted, +in fact, in the same way as did the old ‘Inoculation’ of Small-Pox (p. +183). + +It has been found, however, that the same kind of immunity which is +produced by administering attenuated cultures is sometimes given even +by dead cultures. Nearly all active immunization is therefore done by +inoculating such killed cultures. These are usually called ‘Vaccines’ +from the analogy which they bear to vaccination. The most familiar and +effective ‘vaccine’ is that against Typhoid. Moreover, it has been +found that in certain cases the principle of the induction of Active +Immunity may be applied directly in the treatment of disease. The +conditions that respond best to this line of treatment are those which +present some localized infection, such as a boil or carbuncle. In such +cases we must suppose that, while the local capacity for resistance +is lowered, yet reserves of resistance in other parts of the body can +be brought into play. These reserves are called up by the signal that +reaches them by the reaction of the body against the Vaccine. + +It has been shown that, for the production of Active Immunity, the +actual bodies of the disease organisms are not always necessary. In +some cases, toxins obtained from these disease organisms are themselves +sufficient to induce Active Immunity. The matter may become of great +medical importance in the future and is already applied for Diphtheria +(p. 265). + +We turn to ‘Passive Immunity’. The fact that Immunity can be +transferred from one animal to another via the serum proves that the +immunizing serum contains substances antagonistic to the bacterium +or toxin against which immunity is conveyed. These antagonistic +substances are spoken of as _Antibodies_. A series of very important +observations on Antibodies has been made, and may in time profoundly +modify not only our views of Disease but also our whole conception +of the workings of the living body. We find that it is not only +toxins that stimulate the formation of antibodies. Antibodies can be +elicited also by the introduction into the tissues of the living body +of red blood corpuscles, of embryonic tissue, and of various soluble +tissue-constituents of animal or vegetable origin. We are still only +on the threshold of the investigation of this subject, which may be as +important philosophically as it is therapeutically. + + +§ 13. _Some Practical Applications of Immunity._ + +We may now consider a few special applications of our knowledge of the +defences against bacterial action. + +_Diphtheria_ is a disease in which the characteristic organisms are +found only locally, and in artificially produced cases only at the +site of inoculation. It therefore seemed probable from the first that +the symptoms were due not to the organisms themselves but to poisons +that they threw off, that is to their ‘exotoxins’. This was given +demonstrational form in 1889 by two pupils of Pasteur, Pierre Roux +(1853-) and Alexandre Yersin (1863-), who investigated many of the +properties of these toxins. In the following year (1890) Emil von +Behring (1854-1917), a Prussian Army Surgeon, and Kitasato showed that +it was possible to produce a Passive Immunity against Tetanus by a +serum from an infected animal, the immunity being efficient against 300 +times the fatal dose of Tetanus. Their paper contains for the first +time the word _antitoxic_. Immediately after, von Behring showed that +against Diphtheria, too, immunity could be obtained by injecting serum +from an animal that had been previously injected with living cultures +of the Diphtheria bacillus. This epoch-making discovery of von Behring +was soon given a practical application. It was found possible to induce +a degree of immunity even after the onset of the disease. The first +human case was a child in a clinic at Berlin in 1891. Antidiphtheritic +serum was placed on the market in 1892. In a few years’ time its +administration had become a routine part of the treatment of the +disease. Diphtheria antitoxin is one of the greatest additions to +therapeutics. With competent administration the case mortality of +Diphtheria is one-half or one-quarter of what it is without the use of +Antidiphtheritic serum. (Fig. 119.) + +[Illustration: + +FIG. 119. DEATH-RATE OF CASES OF LARYNGEAL DIPHTHERIA IN PUBLIC +HOSPITALS IN LONDON. Antitoxic serum came into use in London in 1895 +and into full use in 1896. As its application became more general and +as the method of administration improved the death-rate from this very +grave condition progressively fell. ] + +An important aspect of the reaction of the body to the Diphtheria toxin +was revealed by B. Schick of Vienna in 1908. The technique of inducing +it was perfected by him in 1913, and the test is known by his name. +He showed that susceptibility to the disease could be detected by the +behavior of the skin after injection of minute doses into it. It has +thus been found that new-born infants are seldom susceptible and that +the proportion of susceptibles increases up to two years of age, but +that then it diminishes. The actual proportions of susceptibles, as +estimated in a large number of cases in New York City in 1919, are as +follows: + + Of those under 3 months 15% are susceptible + Of those between 3 months and 6 months 30% are susceptible + Of those between 6 months and 1 year 60% are susceptible + Of those between 1 year and 2 years 70% are susceptible + Of those between 2 years and 3 years 60% are susceptible + Of those between 3 years and 5 years 40% are susceptible + Of those between 5 years and 10 years 30% are susceptible + Of those between 10 years and 20 years 20% are susceptible + Of those over 20 years 15% are susceptible + +These figures show why Diphtheria is mainly a disease of childhood +and is relatively seldom encountered in adults. They also make it +evident that steps for protecting individuals against contracting the +disease--‘prophylactic measures’ as they are called--need only be taken +with a fraction of the population. The useful term _Prophylaxis_ is +derived from a Greek word meaning a watchman or guard. It is used to +describe preventive measures against disease in general, but is more +specially applied to that form of protection which is achieved through +the artificial production of Immunity. + +Such prophylactic measures are now available against Diphtheria. +They differ from those in use against any other disease, since the +substance injected is neither the living infective material as in +vaccination against Small-pox (p. 184), nor is it a killed culture of +the organisms as in immunization against Typhoid (p. 268), nor is it +the serum of an immunized animal as in the protective measures against +Tetanus (p. 267). The Toxin itself (mixed with an experimentally +determined proportion of its antitoxin) is now in wide and effective +use as a prophylactic against Diphtheria. The method was proposed by +von Behring (cp. p. 264) in 1913. The details, however, have since +been worked out in the laboratories of the New York City Department +of Public Health and have been mainly the work of W. H. Park (1863-). +The susceptibles are first determined by the Schick test and are then +immunized against the disease. The immunization reduces the likelihood +of contracting the disease to about one quarter. + +Plague differs from Diphtheria in that the organisms, instead of +being local, pullulate throughout the body of the victim. As in the +case of most diseases of this type, the toxins of Plague are chiefly +_endotoxins_, unlike those of Diphtheria, which are _exotoxins_ +(p. 263). Thus, the filtrate of a culture of Plague Bacilli is but +little toxic and confers little or no immunity. Protective vaccines +of a killed culture of Plague Bacilli are, however, prepared, and +these confer considerable immunity. It is claimed that they reduce +the liability to the disease by about three-quarters, and the case +mortality by about one-half. Prophylactic inoculation against Plague +is associated especially with the name of the Russian investigator +Waldemar Haffkine (1860-), a pupil of Pasteur, who was for many years +in the service of the British Government in India, the Plague center of +the world. + +After Diphtheria one of the earliest diseases of which the toxins were +investigated was _Tetanus_. Kitasato found in 1891 that the filtrates +of pure cultures injected into animals are very toxic. A peculiar +feature is the incubation period of some days that occurs between +the inoculation and the advent of the symptoms. This fact had been +referred to, more than two thousand years earlier, in the _Aphorisms_ +of Hippocrates (p. 23). Moreover, it has been found that, soon after +inoculation, the Tetanus toxin disappears from the blood-stream. This, +it has been shown, is due to its affinity for nervous tissue, with +which it rapidly enters into some sort of combination. The fact is of +clinical significance and of therapeutic application. + +By injection of small and progressively increasing doses of Tetanus +toxin into animals, a high and long-lasting degree of immunity to +the disease is produced. The serum of such immunized animals has the +capacity to protect animals susceptible to the disease against an +injection of a fatal dose. It is now a routine treatment to inject +serum derived from an immunized horse into those who have wounds likely +to result in Tetanus. Owing to the rapid disappearance of the Tetanus +toxin from the blood-stream, and owing to its tendency to unite with +nervous tissue, it is important to inject the serum as soon as possible +after the infliction of the wound. In some cases it is advisable to +inject the serum into the sheath that surrounds the spinal cord in +order to give it as rapid access to the nervous centers as possible. +During the Great War prophylactic doses of Antitetanic Serum were given +to every wounded man after 1914. Before the practice was adopted, the +incidence of Tetanus among the wounded was 16 per 1,000. After the +introduction of this line of treatment as a routine, the incidence fell +to 2 per 1,000. Countless lives were thus saved. Antitetanic serum +should be injected as early as possible in every case of a large ragged +wound, especially if contaminated with soil. + +_Typhoid Fever_ differs from Diphtheria, Plague, and Tetanus in that +it can hardly be conveyed to animals. It has thus proved impracticable +to produce anything in the way of passive immunity in man. On the other +hand, there is no disease in which the production of active immunity +by means of Vaccines of dead cultures has been attended with more +favorable results. The researches which led up to the introduction +of active immunization against Typhoid Fever are bound up with +investigations concerning the diagnosis of the disease which are of +wide importance in connection with several other diseases. + +The discovery of Antibodies (p. 262) gave rise to great activity in +their investigation. Among the most interesting and important of the +antibodies is a group which will cause ‘agglutination’ or clumping +of the disease organisms with which they are specially associated. +This reaction is specific for the corresponding organisms, within +certain limitations. Given, therefore, (1) a pure culture of an +organism, and (2) the knowledge of the highest degree of dilution of +the serum containing such an antibody that will cause agglutination of +that particular organism, the physician has in his hands a means of +detecting or excluding infection with that organism. The method was +especially studied by the Parisian investigator Fernand Widal (1862-), +who in 1896 succeeded in making it practicable for Typhoid Fever, and +his name is attached to the test. It is now universally applied in that +disease. Similar tests have been devised for Malta Fever and for other +conditions. + +There are other groups of antibodies that have been investigated. Some +of these possess the power of dissolving the corresponding organism. +They are, therefore, known as _Bacteriolysins_. Their existence +gives a certain insight into the defensive mechanism of the animal +body against bacterial invasion. They are sometimes of practical use +in distinguishing types of disease-producing bacteria. The method +is applicable, for example, in detecting certain types of dysentery +organisms. + +Another group of antibodies act not against bacteria but against +certain specific substances. Antibodies of this type were first +detected by the Belgian workers Jules Bordet (1870-) and Octave Gengou +(1875-) in the year 1900. The physician avails himself of the existence +of such an antibody in the test that is applied for Syphilis, which was +introduced in 1904 by Ehrlich’s pupil, August von Wassermann (1866-), +and is known by his name. + +Of late years a special aspect of Immunity has come into view in +connection with the so-called ‘Carrier Problem.’ With many diseases, +acquisition of Immunity on the part of the patient implies the death +within his body of the organism that has been causing the disease. +There are conditions, however, in which the organisms may lurk in some +individuals long after the symptoms have subsided. These persons may +even contract the disease so lightly that they are unconscious of it, +but nevertheless they become capable of conveying it. Such individuals +are known as _carriers_. Evidently the existence of carriers introduces +special difficulty into attempts to delimit an infective disease in any +population. + +Among the diseases of known bacterial origin that are sometimes +conveyed by carriers are Typhoid Fever, Diphtheria, and Spotted Fever +or Cerebrospinal Meningitis. A special case of the Carrier Problem is +afforded by Infantile Paralysis, a disease due to ‘ultra-microscopic’ +organism--since the virus is ‘filtrable’ (p. 274). This disease, like +that of Cerebrospinal Meningitis, is probably transmitted by carriers +who do not themselves suffer. + +Typhoid Fever, Diphtheria, Influenza, Scarlet Fever, and many other +conditions are often conveyed by ‘ambulant’ cases. This term is applied +to those cases which, while definitely suffering from a disease, do +not regard themselves as ill enough to take to their beds but continue +their ordinary avocations. Such ambulant cases are not less but more +dangerous to their neighbors than those more severely stricken. + +The whole study of the Carrier Problem is in its infancy. It is beset +with extraordinary difficulties. In the case of Diphtheria and Typhoid +Fever, however, the demonstration that a suspected individual is or is +not a ‘carrier’ is easy. The difficulty is to trace him in the first +instance! + + +§ 14. _The Conquest of the Tropics._ + +Nowhere in Medicine has the rational spirit been more triumphantly +vindicated than in connection with the diseases peculiar to hot +countries. The increase in the habitability of the Tropics may be +traced to two main causes. First is the application of the ordinary +laws of Hygiene. Second is the increasingly exact knowledge of the +microbic origin of tropical diseases, leading to a more complete +apprehension and a stricter application of the laws of Hygiene. + +We have glanced at the great changes wrought in the social +organization of temperate countries by the rise of modern Hygiene (pp. +172-78), which commenced to be felt about the middle of the eighteenth +century. The death-rate then began to fall, and has fallen steadily +ever since. The mid-eighteenth century marks, for temperate countries, +the end of the ‘Middle Ages’ of Hygiene. But with the advent of the +modern period the fall in the death-rate in temperate countries has not +been the only change in the public health. Even more significant is a +change in the _causes_ of death. + +Certain diseases have gradually receded from the more civilized and +settled temperate countries, and are now almost unknown there. Thus, +Malaria, Plague, Typhus, Leprosy and Dysentery, once of world-wide +distribution, have come to be regarded as more or less distinctively +‘tropical’ diseases. A time is approaching when we shall be able +to place other diseases with which temperate countries are still +afflicted, such as Typhoid Fever, in the same category. The ultimate +exclusion of Typhoid as a disease of civilized communities is suggested +by the death-rates of England and Wales. + + +_Average Annual Death-rate in England and Wales from Typhoid per +million living._ + + 1871-80 1881-90 1891-1900 1901-10 1911-20 1921-26 + 332 198 174 91 35 24 + +In the category of such removable diseases which, being excluded from +temperate countries, are regarded as tropical are Malaria, Plague, +Typhus, Leprosy, and certain forms of Dysentery. These diseases are +‘tropical’ only in the sense that it is in the Tropics that the general +hygienic conditions most favorable to their development are still +found. If the hygienic conditions of the Tropics could be raised to +those of the civilized temperate countries--a task, it is true, of very +great difficulty--these particular diseases might become as rare there +as they are with us. Indeed, it is possible to foresee a world in which +a number of these so-called tropical diseases will have disappeared +altogether. + +There are, however, other diseases that are tropical in another sense. +Such diseases have seldom or never visited the shores of temperate +countries, or at least have obtained no lasting foothold there, even +when the conditions have been favorable to them. Among such diseases +are Yellow Fever, Sleeping Sickness (which must not be confused with +the so-called ‘Sleepy Sickness’), Beri-Beri, Dengue, Sprue, Kalar-azar, +and a host of other less known conditions. + +It must be said, to avoid misunderstanding, that ‘the Tropics’ in the +medical sense is a region considerably wider and far less well-defined +than the geographical Tropics. Moreover, despite the existence of +diseases peculiar to the Tropics, ‘tropical diseases’ form no natural +group based on any common organic causation. The organisms that give +rise to the various ‘tropical diseases’ differ from one another just +as much as the organisms that give rise to the diseases of temperate +countries. + +Since we cannot speak of tropical diseases on the basis of their +common causation, we are forced to deal with them as separate entities +and especially from the point of view of their prevention. We will +therefore select two diseases, the history of which illustrates the +process by which the Tropics have been rendered safer both for European +and for native races. These will serve as types, and we will choose +one from the truly tropical group which does not invade temperate +climes, and the other from the group which is being gradually excluded +from temperate climes. No better instances of these two groups can be +adduced than Yellow Fever and Malaria. + +[Illustration: + +FIG. 120. A common Malaria-carrying mosquito × 3. + +FIG. 121. The Yellow Fever-carrying mosquito × 3.] + + +(a) _Yellow Fever._ + +In discussing the history of Yellow Fever, as of many other conditions, +it is perhaps best to begin at the end, for modern knowledge of the +organic cause of a disease often illumines and gives a meaning to +historical records. + +In 1918 the Japanese investigator Noguchi observed a very delicate +and minute spiral organism in the blood of a case of Yellow Fever at +Guayaquil, the principal port of Ecuador, on the West Coast of South +America, one of the most important endemic centers of the disease. +Noguchi showed that guinea-pigs inoculated with the blood of this +infected case developed symptoms similar to those of Yellow Fever, and +he was able to demonstrate the same organism in the sick guinea-pigs. +He passed the disease by means of inoculation from one guinea-pig +to another. He succeeded in obtaining pure cultures of the organism +on artificial media. He passed such cultures through a series of +guinea-pigs and finally recovered it in pure culture again. He showed +that different strains vary greatly in virulence, a fact in accord with +the great variability in the gravity of attacks of Yellow Fever. + +One of the reasons why the discovery of this organism has been so long +delayed is doubtless the very small numbers in the blood of patients +suffering from Yellow Fever. Thus, the toxins must be extremely +powerful. Indeed, it has been shown that 1/10,000 of a cubic centimeter +of a virulent culture rapidly induces fatal symptoms in a guinea-pig. + +There are other important points about the Yellow Fever organism. It +passes through a stage in which it is so small as to be beyond the +reach even of microscopic vision. This fact is known because the blood +of a Yellow Fever patient is infective when passed through any but +the finest filters. The organism in fact exists in what is called a +‘Filter-Passing’ stage. Of late years a number of infective diseases +have been shown to be due to filter-passing organisms of this type. +Among them is the organism of the disease known as Infantile Paralysis +(p. 270). The study of ‘filter-passers’ bids fair to be in itself a +special science. + +Finally, Noguchi threw light on the nature of Yellow Fever epidemics. +He was able to pass the parasite from one guinea-pig to another, not +only by inoculation in the ordinary way, but also by means of the bite +of a species of mosquito which has long been known to be the carrier +of the disease for man. He showed that a period of some twelve days’ +duration within the body of the insect is necessary for the parasite +again to develop its dangerous phase. The period of incubation in +man, that is, the time that passes between the infective insect bite +and the appearance of the disease, is 3-5 days, but 12-14 days is the +period that usually elapses after the introduction of a case of the +disease before other cases occur. The discrepancy is now explained. +The disease is not infectious except through the mosquito, so the +developmental period of the parasite within the mosquito corresponds to +the incubation period of the epidemic. + +Outbreaks of Yellow Fever have struck the public imagination, have +given rise to folk tales and have inspired poets. The story of the +_Flying Dutchman_ is that of a ship stricken with Yellow Fever. The +specter ship is supposed by sailors to haunt the seas around the Cape +of Good Hope, and to bode ill for those who see it. A murder was +committed on the ship, and following it ‘Yellow Jack’ broke out. All +ports were closed to the wretched crew, who finally all died of the +disease. The _Flying Dutchman_ was the subject of an opera by Wagner +and a novel by Marryat. A picture of a ship smitten by Yellow Jack is +to be found in Coleridge’s _Ancient Mariner_. + +An historic case may be quoted. In 1837 a barque named _Huskisson_ was +at Sierra Leone. She was lading when Yellow Fever appeared among the +crew. All but two or three died. Yellow Fever broke out in the colony, +but gradually died down. The _Huskisson_, in the meantime, remained in +harbor without hands for three months. At last, hands were obtained, +tempted by very high pay. Again the Yellow Fever broke out among them +and again nearly all died. They were bitten by infected mosquitoes +which remained in the ship during the three months. Many cases, no +less dramatic, are on record. The disease is among those which are +peculiarly common and fatal among medical men. Thus, Senegal has twice +been denuded of medical men by Yellow Fever. In 1830 six died out of +twelve, and in 1878 twenty-two out of twenty-seven. + +An attack of Yellow Fever confers Immunity. In children it assumes a +mild form, and therefore, in countries where the disease is endemic, +the population consists largely of the survivors of attacks. On this +account terrible outbreaks of the _Flying Dutchman_ or _Ancient +Mariner_ type are always either on immigrant ships or in places which +have remained long unvisited by the disease, in other words such +outbreaks occur under conditions in which immune persons are few or +absent. + +The distribution of the Yellow Fever mosquito is wider than the +distribution of Yellow Fever at the present day, but Yellow Fever is +never found, save in sporadic outbreaks, where the mosquito cannot live +permanently. The distribution of the mosquito corresponds, however, +to the areas where the disease has in the past, from time to time, +established itself, but is smaller than the area wherein sporadic +outbreaks have been reported. + +During the seventeenth and eighteenth and even the nineteenth century +there were repeated outbreaks of Yellow Fever far beyond the region to +which it is now confined. Along the eastern shores of North America it +has at times extended as far north as New York, and there have been +destructive outbreaks in Baltimore, Philadelphia, and even Boston. The +disease has been found along most of the littoral of South America. In +the Old World it has visited chiefly West Africa, where it was imported +very early by the slave trade. It has visited at times Spain, Portugal, +and Italy with devastating epidemics, and has even occasionally made a +call in France and once in England. The last considerable outbreak in +Europe was at Madrid in 1878. + +England has always had important interests in the West Indies. During +the eighteenth and first half of the nineteenth century she had, +moreover, large military establishments there, which were regarded as +very bad stations. In Thackeray’s _Vanity Fair_, which refers to the +period just after the Napoleonic wars, the disreputable and unfortunate +Rawdon Crawley is sent as governor to ‘Coventry Island’ in the West +Indies, and is not expected to last long! There are many historic +occasions on which the British forces in the West Indies lost almost +incredible numbers from Yellow Jack, garrisons being practically wiped +out. In Jamaica the mean annual mortality in the garrison was for many +years 185 per 1,000! In the Bermudas the mortality was about 80 per +1,000. One should remember that soldiers are picked men in the prime of +life, and that these mortality rates were in places now regarded as +health resorts! A hundred years ago, Jamaica had the highest death-rate +in the Empire, with the exception of West Africa, where the mean annual +mortality of whites at Sierra Leone was 362 per 1,000! + +Conditions in the West Indies began to improve definitely from about +1850 onwards. At that time there was no effective knowledge of the +organic cause of Yellow Fever, nor, for that matter, of any other +tropical disease. Only lately has the basic reason for this early +improvement become obvious. From about 1850 onwards the water-supply +in the more settled parts of the West Indies, and notably in the +larger towns, came to be arranged by pipes. Now these towns were the +special resorts of the Yellow Fever mosquito. The removal of open +standing water, the enclosure of water-supplies, and the introduction +of ordinary modern sanitation in the clearing away of rubbish, did good +work without any knowledge of the organic cause of the disease. + +We now know the life-course of the Yellow Fever mosquito. We know +her breeding habits and how the water-living larvae congregate +specially in the small collections of water in the neighborhood of +houses. Precautions have been taken against them and under favorable +circumstances the disease has completely disappeared in well-managed +districts under British and American control. The romantic story of +the destruction of Yellow Fever in the Panama zone, in Cuba, Puerto +Rico, Jamaica, Barbadoes, Trinidad, New Orleans, has been too often +recited to be detailed again. Every one has heard of the tragic event +in connection with the American Mosquito Commission of 1900 and of the +death of Lazear. He and his colleagues, led by Walter Reed (1851-1902), +finally proved that the disease is never conveyed by bedding, or by +clothes, or by other objects, but always and only, in nature, by the +bite of an infected mosquito. + +During the experiments of the American Commission, cases of Yellow +Fever were produced in volunteers by bites of infected mosquitoes, by +injection of blood of infected patients, and by injection of _filtered_ +blood serum of infected patients (p. 74). With this knowledge in his +hands, the American chief sanitary officer of Havana, William C. Gorgas +(1854-1920), began to destroy mosquitoes systematically and to treat +all Yellow Fever patients under mosquito nets. Within three months +Havana was free from Yellow Fever for the first time for one hundred +and fifty years. These wonderful results are brought out by a table: + + +_Deaths in Havana from Yellow Fever._ + + _Year._ _Deaths._ _Year._ _Deaths._ + 1885 165 1895 553 + 1886 161 1896 1,282 + 1887 532 1897 858 + 1888 468 1898 136 + 1889 303 1899 103 + 1890 308 1900 310 + 1891 356 1901 18 + 1892 357 1902 0 + 1893 496 1903 0 + 1894 382 1904 0 + +Except for the semi-civilized states of Central and South America, +Yellow Fever is now generally under control. It is perhaps not always +realized, however, that, while the local extinction of this disease +may be among the future triumphs of modern science, its substantial +control over large areas is part of the history of world hygiene (p. +278), and that it is part of the very same movement that has made our +own cities healthier and more habitable than they were in the Middle +Ages. + + +(b) _Malaria._ + +The history of Malaria, which is also carried by a mosquito, is very +different from that of Yellow Fever. Malaria was, till recent times, +a disease of temperate as well as of tropical countries. The old name +for the disease is _Ague_. The word _Malaria_ is of no great antiquity +in the English language. It came into use only in the eighteenth +century. Like the word _Influenza_, it is of Italian origin, and, +like _Influenza_, it carries with it a forgotten pathological theory. +_Malaria_ is simply _mal aria_, that is, ‘bad air’. So _Influenza_ +is _the influence_, that is to say, the influence of unpropitious +planets or comets that were held to rain down poison into the air. It +was believed that these diseases were the result of local atmospheric +conditions. In Rome and the Campagna the natives still believe that +just as the sun goes down the air becomes specially poisonous. + +While the _term_ Malaria is comparatively modern, nevertheless, +recognizable accounts of the _condition_ are perhaps more ancient +than those of any other disease. Of all diseases produced by +micro-organisms, Malaria has perhaps changed its type least during the +course of historic time. The disease is distinctly described in several +places in the _Hippocratic Collection_. + +The conception of diseases as separate entities is, of course, modern. +In the case of most infectious diseases, therefore, we cannot hope +to follow the history very far back. But the symptoms associated +with a malarial attack are so definite that there is no difficulty +in tracing the disease with certainty as far back as 1000 B.C. The +real division into ancient and modern times comes, for this disease, +with the use of Cinchona, which is the plant from which Quinine (p. +326) is now derived. Very soon after the introduction of Cinchona in +the seventeenth century, fevers came to be habitually divided into +those which respond to Cinchona and those which do not. Cinchona--and +therefore its derivative, Quinine--is one of the drugs that we owe +to the discovery of the New World (p. 95). The rind of the Cinchona +tree was taken as a remedy by the aborigines. In Europe, where it was +introduced by Jesuit missionaries, it became known as ‘Jesuits’ bark’. +It was popularized by Sydenham (p. 100) and has ever since been widely +used in medicine. + +[Illustration: FIG. 122. GEOGRAPHICAL DISTRIBUTION OF INDIGENOUS +MALARIA IN ENGLAND AND WALES ABOUT 1860.] + +Sydenham gave a good description of Malaria. During the seventeenth +and eighteenth centuries epidemic after epidemic of ‘Ague’ swept over +England as over other European countries. These epidemics spread from +their endemic centers, the low-lying ill-drained, swampy districts, +where the Malaria mosquito could breed freely in the slowly flowing +water. Of such places the principal in England were the Fens of +Cambridgeshire, Lincolnshire, and the surrounding counties, the marshes +on either side of the estuary of the Thames in Kent and Essex, the +marshes of Romney and Pevensey on the South coast, and those around +Bridgewater near the Bristol Channel (Fig. 122). There Malaria was +never absent, though it differed greatly in prevalence and severity in +different years. Ague remained prevalent in London as late as 1859. +The proportion of ague cases to the total number of in-patients and +out-patients at St. Thomas’s Hospital in London from 1850-60 varied +from between 12 per 1,000 at lowest to over 60 per 1,000 at highest. +Thus, over one-twentieth of the patients in a large London hospital +suffered from what we now regard as a tropical disease, within the +lifetime of men who are still with us! + +In London the rise in the value of land led to the erection of the +Thames Embankment, which effectually reclaimed the land around +the river. Extensive works of drainage were at the same time being +undertaken in other infested districts. These soon had their now +well-known effect. In 1864 Malaria was found to be rapidly diminishing +everywhere, and to have left many of its old haunts. The disease +retreated rapidly. At the beginning of the twentieth century a +systematic search was made for a native case in England. After much +labor one single case was at last found. It may safely be prophesied +that native Malaria will never again be anything but a rare disease in +any temperate country with an efficient sanitary service. + +The story of the discovery of the malarial parasite is worth +recounting. These organisms inhabit the red blood corpuscles and +were first seen by Alphonse Laveran (1845-) in 1880 in Algiers. His +observations were extended by French and Italian observers, who showed +that the sudden rise in temperature in Malaria coincides with a process +of division of the parasite. Later the suggestion that the parasite +might be conveyed to man by the mosquito was made by Patrick Manson +(1844-1922). The matter was clinched in 1898 by Ronald Ross (1857-), +who showed that the malarial parasite necessarily passes through a +stage in the stomach of the mosquito. The process was first traced by +Ross in a malarial parasite that is peculiar to certain birds, and +was subsequently demonstrated for the allied species of parasite that +produces human Malaria. + +We have here an illustration of the value of comparative pathological +studies. Since the demonstration of the life-cycles of the malarial +parasites of man (Fig. 123), the chief attention of hygienists +interested in + +Malaria has been directed to the mosquito (Fig. 124). Controlling the +breeding of the mosquito has proved the best method of reducing the +incidence of the disease. Engineering and sanitary works in some places +previously infested with Malaria have had the effect of almost entirely +eliminating disease. The classical instance is the Panama zone, where, +as is well known, the two mosquito-born diseases, Yellow Fever and +Malaria, have disappeared. There are now many areas in the Tropics, +previously infested, in which the disease is almost unknown. There are +many devices for dealing with the mosquito larvae. + +By advances such as have been made in the knowledge of Yellow Fever and +Malaria, those areas of the Tropics which are under proper sanitary +control have become far safer habitats. There is good hope of an early +and rapid extension of the process, ultimately rendering new areas of +the Tropics suitable for permanent habitation by the white races and +healthier and happier places for the colored. + +[Illustration: FIG. 123. THE LIFE-HISTORY OF THE PARASITE OF MALARIA + +The life-histories of the parasites of the malarial diseases of man +have been completely traced. The parasites run through a double cycle, +one in man and the other in the mosquito. In our diagram the cycles of +only one species are represented; there are however two other special +malarial parasites in man. + +On either side the head of the mosquito involved is diagrammatically +shown, just below the ‘cycle in man’. + +In man the parasites conveyed by the bite of the mosquito (32) or +formed by a division of a parasite already in the blood (7) make their +way into the red blood corpuscles (1 and 2), develop there (3 and +4). Some of them ultimately divide to go through the same cycle (5, +6, 7 and back to 1, 2). The process of division corresponds to the +period of fever. Others develop into crescent-shaped bodies (8, 9 and +10), which can be differentiated into two slightly different forms +corresponding to two sexes (9 male, 10 female). These, if sucked up by +a biting mosquito of the right species, pass into the animal’s stomach +where they develop further (11, 12, 13 male; 14, 15, 16 female) and +end by dividing into forms which conjugate (17). The resultant of this +conjugation or union of the two sexes (17) develops into a lanceolate +form (18, 19, 20) which passes into the cells of the mosquito’s stomach +(21, 22) and finally penetrates these cells (23). The parasite then +secretes a cell-wall and forms a ‘cyst’ (24), which enlarges (25). +The enlargement continues while the nucleus breaks up (26, 27, 28). +In the cyst, which is still growing, a large number of needle-like +forms develop, each of which contains a fragment of the nucleus (29). +Finally the cyst bursts (30), the needle-like forms are cast forth into +the body of the mosquito, and ultimately lodge in her salivary glands +(31). When the mosquito bites another man, she injects some of her +saliva into him through her proboscis. Thus she infects his blood with +some of the needle-shaped parasites that lurk in her salivary gland +(32). So the cycle is re-enacted again and again. We may note that to +prevent this process of repeated reinfection it is only necessary to +break either cycle at one point. Thus destruction of mosquitoes or of +their breeding-places will suffice, or, again, protection of human +hosts from bites of mosquitoes will be sufficient. Either process, if +persisted in, will lead to the extinction of the parasite in the region +under supervision. In England both methods have been in operation and +the disease is almost extinct there so long as any of the malarial +mosquitoes remain in one district. However, the disease can always be +reintroduced by the introduction of subjects of malaria from without. + +(From C. M. Wenyon’s _Protozoology_, Vol. II, by kind permission of +Messrs. Baillière, Tindall and Cox. Slightly reduced in size.)] + +[Illustration: FIGS. 124 and 125. A common Malaria-carrying mosquito +and a common gnat sometimes confused with the Malaria-carrying +mosquitoes. They are both in sitting posture and may be easily +distinguished by the attitude that they then assume.] + +[Illustration: + +FIG. 126. CHART OF CASES OF MALARIA reported in Italy in recent years, +showing the seasonal variation of the disease. The date of the year +is written, in each case, below a vertical line corresponding to +midsummer. It will be seen that the maximum incidence is always in +the months July to September, and the minimum incidence is always in +the months January to March. This incidence corresponds to the known +facts of the life-history of the mosquito and of the evolution of the +malarial parasite within the body of the mosquito. ] + + +§ 15. _The Changed View of Insanity._ + +Insanity is as old as History. The Bible, Homer, and the _Hippocratic +Collection_, for instance, recount numerous examples of the disease. +Until the nineteenth century there was practically no scientific +knowledge of the conditions classed as insanity. Nevertheless, +hospitals for the insane were instituted at an early date. A well-known +instance is Bethlem Hospital or _Bedlam_ in London, which was developed +as an insane asylum in the fourteenth century. + +The new era in the treatment of insanity begins with the abolition of +the old system of restraint. This was primarily due to two noble-minded +men, one a Frenchman and the other an Englishman. Philippe Pinel +(1745-1826), physician at the Bicêtre and afterwards at the Salpêtrière +at Paris, at great personal risk both to his life and liberty, +insisted on freeing from their chains the unfortunate lunatics under +his charge. His _Medico-philosophical Treatise on Mental Alienation_ +(1791) was devoted to championing the humaner treatment of the insane. +His contemporary, the Quaker philanthropist William Tuke (1732-1822), +succeeded in 1792 in establishing at York a small retreat for the +insane, where the antiquated, unnecessary and cruel restraints were +abolished (Fig. 127). + +While Pinel was beginning the humaner treatment of insanity in France, +considerable interest was aroused in the subject in Germany. There, +however, the medical profession was still under the influence of the +mystical Stahl (pp. 132-3), who regarded all forms of insanity as +perversions of the moral tendencies of the soul, produced by sin! + +In France Pinel was succeeded in 1810 by Jean Étienne Dominique +Esquirol (1772-1840). The influence of Esquirol was as radical for +the scientific study of the subject as had been that of Pinel for the +humane treatment of the sufferers. Esquirol threw himself into the +task of founding properly conducted asylums, and he produced in 1838 +his monumental work _On Mental Diseases considered in their Medical, +Hygienic, and Legal relations_. It is the first important, rational, +scientific treatise on the subject. Esquirol abandoned the barren type +of speculation that had characterized previous works on the subject +and devoted himself to the systematic collection of data. He was able +to sketch out some of the main forms of insanity, including that now +known as ‘General Paralysis of the Insane’. This disease was finally +differentiated by one of his pupils. Another pupil of Esquirol was the +first to succeed in the training of idiots. The main school of French +alienists is descended from Esquirol. In the early forties his work +resulted in the foundation of journals and societies devoted to the +study of Insanity in France, England, the United States, and Germany. + +England was behind France in her treatment of the Insane. Not until +1828 were there proper laws governing their certification. In 1844 the +great and good Lord Shaftesbury (1801-85), the seventh Earl, brought in +his Bill establishing the Board of Lunacy Commissioners with the duty +of inspecting all lunatic asylums. It was a subject to which that great +philanthropist gave much thought. The same period saw also an awakening +in the United States, where Miss Dorothea Lynde Dix (1802-87) carried +on a very successful campaign for the better treatment of the insane +and the establishment of proper houses for their reception. Her labors +resulted in the foundation of many asylums on a reformed model in the +United States and Canada. In 1845 the provision of asylums out of the +local rates was made compulsory on the local Justices in England. + +The late sixties and early seventies saw in every country a further +change for the better in the treatment of the Insane. The causes of +this improvement were two. On the one hand, Insanity came generally +to be recognized as a group of diseases which, like other diseases, +have usually a traceable physical basis. On the other hand, the great +improvement of the system of nursing under the inspiration of Florence +Nightingale (pp. 298-300) began to reach the asylums. In 1877 there +was a Parliamentary investigation into the care of the Insane in +England and Wales, and in 1890 the duties of asylum administration were +transferred from the Justices to the County Councils. This has resulted +in an immense improvement in the accommodation and treatment of the +insane poor in England. At the same time the order of a magistrate +became necessary for the consignment of a private patient to an asylum. +In 1913 provision was made for the mentally defective, who do not come +within the Lunacy Act. Lastly, with the establishment of a Ministry of +Health in 1917, the general control of the Insane has passed to that +body. + +Many types of insanity have been traced to an organic cause in the +Nervous System itself. The Morbid Anatomy, both coarse and microscopic, +of some of these diseases has become recognized. Chief among them is +the well-known condition known as ‘General Paralysis of the Insane’. +During the intensive study of the factors in the causation of Insanity +it has become clear that in some groups, as in General Paralysis, which +is always preceded by Syphilis, a ‘toxic cause’ is at work. Other +types of toxic insanity are due to the actual intake of a poisonous +substance. This is sufficiently evident in cases which are associated +with Alcoholism. There is also evidence that in a considerable +number of cases toxic conditions result from perversion of metabolic +processes, or, again, are associated with ‘deficiency’ states (pp. +302-8). This is a very hopeful finding, since by removing the toxic +cause, or by remedying the deficiency, relief may be possible. + +Much less hopeful is the outlook with those forms of insanity, +especially common in the adolescent, which are of the nature of a +perversion of development. Such is the large group known as ‘Dementia +praecox’. These cases almost invariably originate from a mentally +unsatisfactory stock. This is less so with the Epileptic insane, though +a considerable proportion of epileptics may be classed with those +who are born mentally defective and are liable to give rise to a bad +stock. Whatever view may be taken of the question of the artificial +limitation of human fertility, it is almost impossible to imagine that +the free breeding of these classes of defectives, epileptics and their +congeners, will continue unchecked in any civilized community. + +The general care and treatment of the insane has improved out of +all knowledge during the last quarter of a century. It is probable +that there is now no class of sick person who is more skilfully and +considerately cared for. + +From time to time an alarm is raised at the rapid increase in Insanity, +and it is a fact that the proportion of certified insane has been, +for some time, steadily rising. A considerable part of this rise is +certainly due to the greater willingness of the insane themselves to +enter an asylum, and of their friends to allow them to do so. Part of +the rise in numbers of the insane is due to their increased length of +life under improved treatment. It must be remembered that more than 90 +per cent. of the insane in England and a similar percentage in other +countries are paupers, who are not readily discharged as they have no +means of support. Mild mental cases and the senile insane go now to +the improved asylums. Before they would have been kept at home or sent +to a rate-supported or a State infirmary. The general conclusion of +those best qualified to judge is that Insanity, if increasing at all, +is doing so only very slowly. + +[Illustration: FIG. 127. ‘THE RETREAT’ NEAR YORK FOUNDED IN 1792 + +being the first institution in England where the insane were accorded +humane and scientific treatment.] + + +§ 16. _The New Movement in Psychology._ + +During the last half-century various new points of view have entered +into our conception of Mind and its disorders. The evolutionary view +of the origin of man, which was brought to wide notice by Charles +Darwin, not only in his _Origin of Species_ of 1859 but also in his +_Descent of Man_ of 1871 and his _Expression of the Emotions_ of 1872, +has given rise to new ideas as to the nature of many instincts and +emotions. These views have been co-ordinated with our knowledge of +lower types of man, both in his existing state and in his extinct and +fossil forms. Much that we call Insanity has been found to be related +to what is normal in other and less developed environments. The Mind, +breaking free from its habitual restraints, ‘reverts to a lower type’. +There is a constant though unconscious ‘conflict’ in the mind, which is +variously resolved. + +Whole schools of Psychology have arisen in the discussion of the nature +and resolution of these conflicts. Sigmund Freud of Vienna (1856-) +takes the leading place among those who have dealt with this subject. +He holds these conflicts to be rooted in sex and has introduced +the method of _Psycho-analysis_, which lays great stress on the +subconscious or unconscious element in mental life. Largely under the +direction of C. G. Jung of Zürich (1875-), preventive and curative +measures, based on this view, have been introduced into medicine. +It has been established that painful experiences, lurking in the +unconscious mind, disturb the equilibrium of health. Such disturbance +is often of the nature of a struggle to repress into the unconscious +unpleasant memories which are tending to surge up into the conscious. +The psycho-analyst seeks to release the repressed experience into the +conscious. The recognition and consideration that follow a success in +this attempt is often far less painful than the repression. Persistent +unreasonable fears on the part of adults, but especially of children, +are frequently thus dispersed. + +The importance of suitable environment to children has always been +recognized. But a new significance has been given to the mental +impressions received in infancy by cumulative evidence of harmful +results in the adult life of events in the early years of life that +are seemingly forgotten. This recognition of the enduring character of +mental impressions has led to a movement for the better instruction of +mothers, and has thus been a factor in the remarkable development, in +recent years, of work for infant welfare. + +It is recognized, moreover, that certain instincts--such, for +example, as the self-regarding instinct and the sex instinct--must +have expression. Mere repression of such instincts is always harmful, +but they are susceptible of a process of transformation, technically +known as _sublimation_, to an almost indefinite extent. Thus the +self-regarding impulse need by no means lead to the inconvenience and +discomfort of others, but, rightly guided, may develop into a sense +of personal responsibility for the welfare of others. So, too, sex +instinct is but one aspect of that creative vital activity on which +depends the continuance not merely of the human race but also of the +culture that the race has built up. The sex instinct is thus habitually +sublimed into other creative channels, and there are many altars, +beside those of Venus, at which young men and women may kindle their +essential fires. + + +§ 17. _The Revolution in Nursing._ + +During the Middle Ages, and in Catholic countries after the +Reformation, attendance on the sick in Hospitals and elsewhere was the +task of religious sisterhoods. In Protestant countries the absence of +these sisterhoods necessitated the employment of women specially for +the purpose. The task was not an attractive one, nor did any social +distinction attach to it. The profession of nurse became despised +and was followed, for the most part, by a low and illiterate type of +woman, though midwives were sometimes better educated and of a higher +class (p. 180). The great philanthropists of the eighteenth century +(pp. 171-72) could do little to improve the nursing profession. +The conditions of employment formed the root of the evil. The vast +improvement that has resulted in health and happiness to our whole +population from the improvement in the character and training of nurses +is probably seldom realized, even by medical men. Yet it may reasonably +be doubted whether all modern medical and surgical advances put +together--apart from Preventive Medicine and Infant Hygiene--have saved +as many lives as the Reform of Nursing. + +The reader may gain some insight into the life of a nurse from the +conditions that prevailed until beyond the middle of the nineteenth +century at a very good and well-managed English provincial hospital, +the Radcliffe Infirmary at Oxford. The salary of a nurse was £5 a +year. There was no distinction between a nurse and a domestic servant. +One nurse only was the allowance for a ward of seventeen patients. A +nurse’s day began at 6 a.m. The wards were cleaned till 7, when a bell +was rung and each nurse had to bring down her ashes and sift them under +the direction of the porter, who then gave her coals for the day. She +took breakfast with the patients, who helped her, so far as they were +able, with the ward work. At 2 p.m. she went to the servants’ hall, +where she had her dinner in company with the servants on daily hire. +During the dinner the ward was left in charge of a patient. After +dinner she took away a plate of meat and vegetables for her supper. For +the night there was normally only one nurse for the whole hospital of +about 100 beds. There were no regular holidays, and the nurse was never +allowed to leave the hospital before 6 p.m. The practice of nurses +receiving gratuities from patients continued till 1870 and even beyond. +Those patients who wished to secure a nurse’s early attention for their +dressings gave tips, those who did not frequently had to wait. + +What sort of woman could such a system produce? That some nurses at +least were kind and skilful, even under such conditions, is a fact, and +is pleasing evidence of the natural goodness and wisdom that reside in +the human heart. Many, however, can have been no better than Sairey +Gamp and Betsy Prig. + +The first important reform in Protestant countries began in Germany, +through the influence of Elizabeth Fry (p. 171). In 1822 Theodor +Fliedner (1800-64), the young pastor of the church at Kaiserswerth, a +little town on the Rhine near Düsseldorf, visited England and was much +impressed by Elizabeth’s teaching and example. Returning to his charge, +he devoted himself to the spiritual and physical care of jail-birds. In +1833 he and his devoted wife Frederica (1800-42) opened a refuge for +discharged female convicts. From them the couple turned their attention +to the sick poor. The conception of an organized body of specially +trained women crossed their minds. In 1836 they opened a small hospital. + +At this hospital six young women of the most spotless character were +induced to serve as ‘deaconesses’. It was their duty to perform all +the tasks of the hospital in rotation. The physicians who attended the +hospital gave them instruction. The Kaiserswerth idea rapidly spread +and the ‘Kaiserswerth Deaconesses’ became and remain an important +order, which is still occupied in good works in many parts of the +world. The conception of the order is different from that of most +religious orders in that the members make no attempt to withdraw from +the world, and marriage is not forbidden to them. Moreover, the duties +of the Kaiserswerth deaconesses are rather different from and more +varied than those of a sick-nurse. They include teaching, both secular +and religious, nursing, household duties, management of children and +convalescents. In 1865 a preparatory school for probationers was opened. + +In England Anglican orders of a somewhat similar character were formed +in the forties and fifties. In 1850 and 1851 Florence Nightingale +(1820-1910), who was a lady of good social rank, visited Kaiserswerth, +and went through a regular training there. She was profoundly impressed +by the extremely high character of the deaconesses, most of whom were +only peasant women. The next three years she spent in writing and in +examining hospitals in her own country. + +Florence Nightingale’s opportunity came with the outbreak of +the Crimean War in 1854, and the rapid breakdown of the medical +services, which contained no women nurses. The French had a number +of ‘religieuses’ to nurse their sick, and a feeling of shame arose +in England at the neglect and mismanagement of the British sick and +wounded. The Secretary of State for War asked Florence Nightingale to +go to the Crimea to organize a nursing service. She left at once with +thirty-eight nurses whom she selected personally. Ten of these were +Roman Catholic sisters and all the others had had nursing experience. +From that event dates the Revolution in Nursing. Florence Nightingale +performed marvels under conditions of great difficulty (Fig. 128) and +in the face of determined opposition. She returned home in 1856 a +national heroine. She had no difficulty in establishing a school and +home for nurses at St. Thomas’s Hospital in London in 1860. The example +was followed by the other London hospitals. + +Florence Nightingale was a woman of the most powerful will and an +admirable organizer and administrator. Her system of nursing contained +many new features, not quite all of which have stood the test of time. +That nursing rapidly and steadily improved from the moment she was in +authority cannot at all be doubted. Looking back, it is apparent that +the immediate success of her methods was due to two main factors. First +was her capacity to secure women of high character and good social +position to accept positions of responsibility. Second was her removal +of the control of the nursing staff entirely from the hands of men into +those of women. Her influence soon passed across the Atlantic, and she +was associated with the United States Sanitary Commission and the women +who took charge of army nursing during the American Civil War. + +While Florence Nightingale was reforming Nursing, her contemporary, +Mary Carpenter (1807-77), was applying herself to the kindred task +of looking after neglected children, establishing Reformatory and +Industrial Schools and improving the position of Indian women. She +obtained a large measure of public support and exercised considerable +influence in America, which she visited in 1873. Many other +distinguished and devoted women worked on similar lines. + +Among the indirect results of the activity of Florence Nightingale was +the establishment at Geneva in 1864 of the International Red Cross +Committee, the branches of which have done good service in many wars +and have been no less useful in peace. + +Florence Nightingale opposed anything in the way of State registration +of nurses. Concentrating on a high ideal of competence and character +for the nurse, she failed to grasp some of the secondary effects of +her own scheme. A large nursing service is now a necessity in every +civilized country, as a result of her efforts and example. Having +regard to human imperfections, we can as little hope that every woman +who nurses will be a born nurse, devoted to her task, as that every +doctor or teacher will have a natural vocation for his work. In an +imperfect world mankind must protect itself against the incompetent and +the unfit. Registration is a way--doubtless an imperfect way--of doing +this. A Nurses’ Registration Act became law in England in 1919. + +There have been many improvements in the details of the training of +nurses, incident on the changes in Medicine and Surgery during the last +half-century. Apart from these, the main improvements in Nursing have +been due firstly to an increased interest in the welfare and health +of the nurse herself, and secondly to the recognition that Nursing is +a profession for which, as for Medicine, some preliminary scientific +knowledge should precede professional training. Thus, the very long +hours of the nurse have of late been reduced, and in the best schools +instruction is now given to nurses in Anatomy, Physiology, Hygiene, +Bandaging, and Cookery, before the commencement of actual hospital work. + +Further developments will probably be along the lines of State and +Municipal Nursing Services. Since Health is a public as well as a +private concern, the same must be true of the training and work of +nurses. + +[Illustration: FIG. 128. FLORENCE NIGHTINGALE RECEIVING WOUNDED AT +SCUTARI + +_From a painting by Jerry Barrett_] + + +§ 18. _Some Modern Physiological Concepts of Clinical Import._ + +The vast activity in the sciences of Physiology and Pathology during +the last fifty years, and their repeated divisions into independent +sciences, each prosecuted by its own specialists, have yielded many +ideas which have been imported into the clinical practice of Medicine. +It is impossible to say which of these are of permanent value. All +previous ages have had to discard part of the practice and a large +proportion of the medical ideas that have been handed down to them, and +there is no reason to suppose that the age that follows us will differ +from those which have gone before us. Some ideas that have entered +Medicine from the physiological laboratory, pushed by interested +parties or seized on in despair by physicians at a loss for a line of +treatment, are already seen by men of experience and judgment to be no +permanent addition to our store. Other lines of physiological thought +are still under discussion by them. + +There are, however, certain physiological conceptions which, apart from +their general implications in the economy of the body, have received +such wide application that their future, as an organic part of medical +practice, seems assured. Certain of these conceptions demand discussion +in even the most cursory survey of medical development. + + +(a) _Ductless Glands and Internal Secretions._ + +The nature and action of the various glands of the body has been a +classical physiological field. Malpighi (pp. 116-20) was the first to +investigate the structure of these organs, and he was followed by many +others. It became evident that many glands, such as the liver, the +salivary glands, and the tear glands, are provided with ducts or tubes, +which carry off the characteristic secretion of the glands. These +secretions can be examined with comparative ease--as happened early +with the secretion from the stomach, or ‘gastric juice’ (pp. 146-48), +and later with the secretion of other glands. There remain, however, +certain glands unprovided with ducts. The action of such ‘ductless +glands’ long remained a mystery. Of these the type is the ‘Thyroid +gland’. Much of our physiological knowledge of this organ, together +with the conception of its function as indispensable to normal life, +has come through Surgery. + +It had long been known that certain symptoms were associated with +enlarged Thyroid gland or ‘Goitre’. Attempts to remove the organ +surgically were made after the introduction of antiseptic methods. +Goitre is particularly common in Switzerland, and it is not remarkable +that the technique of the very dangerous operation for the surgical +removal of goitres was first perfected by Swiss surgeons, among whom +Theodor Kocher (1841-1917) has taken the first place. The study of +cases that had had their Thyroid glands removed gave a clue to the +nature and action of the gland. + +It was found that those surgically deprived of the Thyroid gland +develop abnormal slowness in movement and response. The temperature is +low, the pulse small, the muscles are torpid and sometimes rigid, and +there is a failure in ordinary fine muscular movements. The patient +shows a thickening and swelling of the skin and presents a dull and +very characteristic appearance. When the operation was performed on +one whose growth was not yet complete, development was checked. Such a +patient remains infantile or childish both in body and mind. + +The conditions were recognized by Swiss surgeons in the seventies +as resembling those of a spontaneous disease to which the name +_Myxoedema_ was attached. Further the close relationship both of the +surgical and of the spontaneous condition to the state of idiocy known +as _Cretinism_ came gradually into view. In Switzerland, as in other +parts of Europe, stunted beings known as _Cretins_ had long been known. +These defectives are sometimes goitrous, sometimes without a Thyroid +gland, but their general appearance and condition is an exaggerated +version of what has been described for those with Thyroid glands +removed (Fig. 129). + +[Illustration: FIGS. 129 and 130. CRETINOUS INFANT BEFORE AND AFTER +THYROID TREATMENT. + +_From the Collection of the Royal College of Surgeons._] + +The result of these observations was to direct the attention of +physiologists to the Thyroid gland. It was soon found that the symptoms +of Thyroid deprivation could be experimentally produced in animals. +Moreover, it was shown by Moritz Schiff of Berne (1823-1890), in +1884, that the results of the removal of the Thyroid might be avoided +if the animal were fed regularly on an extract of the glands. The +results were soon applied to man and have led to one of the greatest of +medical triumphs. By its means sufferers from myxoedema and cretinism +can be either cured or improved. A drivelling and idiotic cretinous +child, adequately treated with Thyroid, enters on a normal process +of development. The improvement is almost incredible, and the child +rapidly passes into a healthy and happy state, so that it is literally +true to say that his own parents would not recognize him (Fig. 130). +Further, the gland may be given in excessive doses, and a condition +produced that closely resembles a well-known pathological condition +known as ‘Exophthalmic Goitre’, which is similarly susceptible of +experimental investigation. + +The facts here enumerated justify the deduction that the Thyroid +gland secretes something which is essential to normal well-being. The +organ has no duct, and the secretion is, therefore, never normally +thrown out of the body. The Thyroid is, in fact, an organ of what is +called ‘internal secretion’. Investigations on this secretion led to +the isolation of the active principle as a pure compound known as +_Thyroxin_ in 1916. The story of the Thyroid has recently (1926) been +rounded off by the preparation of Thyroxin synthetically. The synthetic +product has been given with effect in cases of Myxoedema. + +The observations made on the Thyroid directed further attention to +other ductless organs of which a number have been shown to have their +own ‘internal secretions’. Furthermore, it has been demonstrated that, +among organs which throw out their products through a duct, there are +those which also send an internal secretion into the blood-stream. +Among these are the essential organs of sex, the testicle and ovary. +The effect of castration on the general physique is well known. It may +be compared with the effect of ‘spaying’ or the removal of the ovary. +This operation leads to an assumption by the female, in more or less +modified degree, of the secondary sexual characters of the male. + +Peculiarly interesting for their practical results have been certain +investigations made of late years upon the organ known as the +‘Pancreas’. The Pancreas has a duct which opens into the Intestine +just below the Stomach. It has long been known that the secretion of +the Pancreas is related to the amount and fate of sugar in the blood. +The association of disease of the Pancreas with the symptom known as +‘Diabetes’, in which sugar appears in the urine, was also familiar. +Later it became apparent that it was not the Pancreas as a whole that +was related to the process but only certain isolated and peculiarly +formed nests of cells. It is now possible to administer extracts of +these cell-nests with very favorable results on the course of certain +types of Diabetes. The extract is now in wide use under the name of +_Insulin_. + +Among the ductless glands that have been best investigated are the +so-called ‘suprarenal bodies’, which lie above the kidneys. As with +the thyroid gland, the attention of physiologists was directed to +these bodies as a result of clinical observations. These observations +date back to the middle of the nineteenth century. In the last years +of that century it was observed that an extract of the suprarenal +bodies, injected into the circulation, caused a rise in blood-pressure, +an effect opposite to that following the extirpation of the glands. +The administration of extract from suprarenal bodies has found wide +clinical application. Unlike the extract of thyroid, the effect of this +extract is very temporary. It is easily oxidized and rapidly disappears +from the blood. It belongs to the group of substances which are +known as _hormones_. The active element in a suprarenal extract, the +‘suprarenal hormone’, has been recently prepared by a synthetic process. + +The nature of hormones has only come clearly into view of late years. +The word ‘hormone’ is formed from a Greek word meaning ‘to excite’. +The internal secretions have, in general, functions of considerable +physiological complexity, and act, for the most part, slowly and +continuously. The hormones are, however, exceptions to this rule. They +act rapidly and in an excitatory manner. These substances appear to be +of relatively simple chemical structure. They are easily oxidizable, +so that they rapidly disappear from the body. They act, in fact, as +‘chemical messengers’, producing a state of ‘chemical correlation’ of +the different parts of the body which is comparable to the better-known +and more widely recognized ‘nervous correlation’. + +The hormones represent a very ancient and primitive physiological +mechanism. In organisms consisting of but one cell, in which there +are very few differentiated organs, the messages from one part of the +body to another are necessarily of a chemical or hormonic character. +In higher multi-cellular animals the intercommunication between +different parts of the body is maintained, for the most part, by a +specially developed nervous system. Certain necessary messages are, +however, still conveyed by chemical messengers. The development of +the conception of hormones has been especially the work of the London +physiologist E. H. Starling (1866-1927). + +Internal secretions and especially hormones form part of the +increasingly complex picture of the working of the animal body. They +are not only of great physiological value, but have also entered +the department of practical therapeutics. They are, moreover, of +philosophical importance, since they yield us a conception of the body +in which every part is dependent on every other part, and the whole is +subject to a process of ‘integration’ or linkage into a unitary system. +We have glanced at the mechanism of chemical integration. We have now +to turn to the mechanism of nervous integration. + + +(b) _Nervous Integration._ + +If the simple reactions of animal bodies are tested, it will be found +that they clearly serve certain ends. Lightly touch the foot of a +sleeping child and it will withdraw it. Tickle the ear of a cat and +it will shake it. Exhibit savory food to a hungry man and at once +his digestive process will get to work--his mouth will ‘water’. +These instances might be multiplied a hundredfold. Such reflexes +are admirably adapted to their ends. Many of them will continue +in an animal in which the spinal cord is severed from the brain. +Nevertheless, in the higher animals, and especially in man, they are +controllable to a greater or less extent by the will. But to leave the +question at that would give a false idea of the extremely complex +integrative functions performed by the nervous system. Thus, the +spinal cord, which, to the naked eye, is a longitudinal and little +differentiated nervous mass, is, in fact, a collection of nerve-centers +which have historically, both in the individual and in the race, been +formed by the union of a series of separate segments. Each one of these +segments is dependent on the action of the next segment in a fashion +somewhat similar to that in which the actions of the cord itself are +dependent on the brain. Each of the sections governs certain functions +or movements of the body. There is thus a very complex process of +integration which runs right through the nervous system. + +The investigation of the bodily functions of a chemical and physical +nature reveals that these activities are far more largely under +nervous control and discipline than was at one time conceived to be +possible. Thus, the main factor in the activity of any part is its +blood-supply, but the blood-supply is largely determined by the state +of contraction of the vessels of supply, which are in their turn under +nervous control. So it is with the state of nutrition of the muscles, +with the action of the sweat glands of the skin, with the mechanism of +childbirth, and with a thousand bodily states with which both physician +and biologist are concerned. + +The investigation of nervous integration is especially associated +with the name of Sir Charles Sherrington of Oxford. As the outcome +of his work the picture formed of the nervous apparatus is that of a +machine in which some parts work spontaneously, automatically, and with +complete uniformity; others, though mainly automatic, are susceptible +of various degrees of alteration and adjustment; others need +intermittent or constant attention, and demand for their functioning +fresh supplies of energy at longer or shorter intervals; while, +finally, others have hardly yet taken a fixed form and are improvised +as occasion demands. Thus the nervous system is a system of systems of +every degree of independence. + +These systems, each with a certain individuality of its own, date from +every stage of Evolution, the more ancient being, as a rule, the more +automatic and the less dependent on other systems. The most ancient, +the chemical messenger or ‘hormonic’ system (pp. 306-8), we share with +the lowest living things which consist of only one cell. Very recent +are the factors in the nervous system that are specially developed in +man as contrasted with the higher apes. Such are those associated with +the delicate co-ordination of sensory impressions and motor impulses +involved in such acts as speaking, reading, writing and the like. Each +of these systems, high or low, ancient or recent, has its own place +in the body. For many the exact position of the controlling center is +demonstrable and some of the lower systems can function without the aid +of any other systems save those which control their nutrition. + +Among these nervous relations there is one which calls for special +mention on account of its great clinical importance. The state +of ‘shock’, the general nature of which is vaguely understood by +everybody, has been given a more exact physiological meaning of late +years, especially by the American surgeon G. W. Crile (1864-). It has +been found possible to localize ‘shock’ experimentally. If a section +of the spinal cord of an animal be cooled to a point just above +freezing, the part of the body below the cooled level passes into a +state of ‘shock’, that is to say, its reflexes no longer respond to +irritation in the normal fashion. This shock effect is due to the +removal of some influence exercised by the higher parts of the nervous +system. In the experiment the shock effect is induced by an external +agent, but there is an internal mechanism within the nervous system +itself, which can cause it under appropriate conditions. + + +(c) _Vitamins._ + +There are no current medical problems that are more discussed than +those of nutrition. It has long been recognized that articles of diet +may be classified according to their constitution into ‘proteins’, +‘carbohydrates’, and ‘fats’. If an animal is fed on a diet containing +these in correct proportion, but in a perfectly pure state, it will +become ill and ultimately die. The onset of illness and death will be +the more rapid if it be a young animal. This fact, observed as long +ago as 1880, was reinvestigated by F. Gowland Hopkins of Cambridge +in 1906, from whence dates our real knowledge of a very important +subject. He found that, in the case of rats, the addition of a very +small quantity of milk to this chemically pure diet would induce normal +growth. The milk must therefore contain some growth-promoting substance +or substances other than protein, fat, or carbohydrate. The result of +many similar experiments by a large number of observers has shown that +almost all fresh food contains such growth-promoting substances. They +have been named ‘vitamins’. + +Several of these vitamins have been distinguished. None, however, +has been isolated, and we depend for our knowledge of them on our +investigation of their mode of action. One, known as _Vitamin A_, +is produced in the growing green parts of plants, and is especially +necessary for the promotion of growth. Vitamin A is abundant in +cod-liver oil. It has been shown that the necessity for Vitamin A +can to some extent be evaded if the animal is exposed to sunlight or +ultra-violet rays. Moreover, it has been shown that the absence of +Vitamin A or of some allied substance is associated with the disease +of the bones known as ‘Rickets’ or ‘Rachitis’. The history of this +disease (p. 181) is made intelligible by our knowledge of these facts. +Rickets can be shown to be most prevalent under precisely those social +conditions in which articles of diet containing Vitamin A are scarce +and the amount of sunlight is inadequate. + +Our knowledge of this topic is in the process of active extension. +The question of the actual influence of sunlight and of the rays of +various wave-length which go to make it up is still too uncertain for +discussion here. There is a special aspect of this topic, however, to +which we may refer. It has been demonstrated that stable-fed cows, fed +not on fresh food but on oil-cake, yield milk of little antirachitic +power. It has, however, been shown that this milk becomes antirachitic +after exposure to ultra-violet light. Therefore, some antirachitic +substance is produced in the milk, as in the body, by the action of +ultra-violet light. Now recent research has shown that the antirachitic +elements are associated with a chemical substance known as _Cholestrol_ +which is of the nature of a complex alcohol. Nevertheless chemically +pure Cholestrol has no antirachitic power, though it, too, acquires it +by exposure to ultra-violet light. By chemical means 99·9 per cent. of +rayed and antirachitic Cholestrol has been recovered as pure Cholestrol +without antirachitic power. Therefore the antirachitic power, that is +the vitamin factor, resides in the remaining one-tenth per cent. of +rayed Cholestrol. The further investigation of this fraction may be +expected to yield results of great importance both theoretically and +practically. + +Another substance of the same order exists in the husks of rice. If +animals such as fowls be fed on a diet of rice deprived of its husks, +they develop a nervous affection. Now a somewhat similar nervous +affection known as ‘Beri-beri’ is known in the East among natives who +live on milled rice. The disease, whether in human beings or chickens, +may be cured or avoided by giving the husks of the rice separately. +The substance thus conveyed has been named _Vitamin B_. There is yet +another disease, Scurvy (p. 170), which occurs in those who have been +deprived of fresh food. _Vitamin C_, which cures this, is specially +found in the juices of oranges and lemons. Our knowledge of ‘deficiency +diseases’, of which Scurvy is one, is only just beginning. It may +well be that they are of wider occurrence than has been supposed, and +vitamins may be important curative and preventive agents. + + +§ 19. _Knowledge of the Eye and its Disorders._ + +From an early date the treatment of ailments of the eye has stood +somewhat apart from the rest of medical practice. Moreover, the +knowledge of the structure and functions of the parts of the eye has +not kept closely parallel with that of other departments of anatomy +and physiology. + +[Illustration: FIG. 131. DIAGRAM TO SHOW THE STRUCTURE OF THE EYE, +REPRESENTED IN SECTION. For description see pp. 314-15.] + +The eye is a roughly spherical organ, enclosed in a tough capsule, the +_Sclerotic coat_ (Fig. 131). The transparent front of this capsule, the +_Cornea_, is the curved window through which we look upon our world. +There is a watery space, the _Anterior Chamber_, behind the Cornea, +at the back of which is situated the _Lens_, a horny transparent +structure. In front of the Lens is a ring-shaped pigmented muscle which +shuts out light from the Lens, except at the center, and gives the +characteristic color to the eye. This circular colored muscle is the +_Iris_, and the hole in its center is the _Pupil_. The pupil becomes +smaller or larger with contraction or expansion of the Iris. This +change is a reflex and unconscious act, depending on the amount of +light and also on the degree to which the eye is adjusted to examine +near objects. + +The edge of the Lens of the eye is attached by the circular _Suspensory +Ligament_ to the circular _Ciliary Muscle_. The Ciliary Muscle, by +contracting or relaxing, alters the form of the Lens (Fig. 132). +This change in form of the Lens is part of the process of adjustment +to near or distant vision. Behind the Lens is the large _Posterior +Chamber_, containing a transparent gelatinous substance. At the back +of the posterior chamber is the sensitive area or _Retina_, which is +the essential organ of vision, and is backed by a pigmented coat, the +_Choroid_. The Retina is continuous with the _Optic Nerve_, along which +an artery enters the globe of the eye. At the point where this artery +pierces the Retina there is the so-called _Blind Spot_. + +A ray of light penetrating the eye from the center of the Cornea +through the center of the Lens falls on or near a specially sensitive +area, the _Yellow Spot_, and images formed there are more distinctly +perceived than those formed elsewhere. When an object is examined +closely, the observer makes the attempt to bring the image of it on +to his Yellow Spot. Any injury to the Yellow Spot causes a great +diminution in clearness of vision. Man and his allies, the zoological +group known as the ‘Primates’, are the only mammals, except the cat +tribe, that possess a Yellow Spot. There can be little doubt that the +possession of this Yellow Spot has done much to raise the importance +of vision among the senses in the Primates. It has thus been a very +potent factor in the evolution and elevation of Man himself. + +The eye is an optical instrument which, like other instruments, +performs its functions with something less than perfection. Most purely +optical errors of the eye can be remedied by spectacles. These aids to +vision are of very great importance, since, by the time middle life is +reached, few are fortunate enough to read in comfort without them. The +introduction of spectacles, therefore, enormously extended the active +intellectual life. Their social effects are incalculable. + +The commoner optical errors may be classified under four heads. + +First and commonest there is ‘old sight’. When a healthy eye adjusts +to near vision, the Ciliary Muscle contracts towards its attachment +at the junction of Conjunctiva and Sclerotic. This draws forward and +relaxes the Suspensory Ligament. The elasticity of the Lens, no longer +constrained by the Ligament, causes it to assume a more convex form. +This more convex form is appropriate to the correct focussing of a +near object on the Retina. At or about the age of forty-five the Lens +usually begins to lose its elastic power, and thus has difficulty in +adapting to near vision. The trouble is remedied by the use of convex +glasses for reading or other near work. + +A second common error is the so-called ‘far sight’. In this form--save +in extreme cases--the eye is competent for distant objects, but those +that are near are not clearly seen. The incapacity for near vision is +due to a deformity--usually innate--of the eye. The eye is too short +along the axis _xy_ (Fig. 131). The resulting optical error can be +remedied by the use of convex spectacle lenses. + +[Illustration: + +FIG. 132. DIAGRAM TO SHOW THE NATURE OF ACCOMMODATION OF THE EYE TO +NEAR VISION. The Ciliary muscle, by contracting, pulls forward the +lateral attachment of the Suspensory Ligament to the Sclerotic. Thus +the ligament is relaxed and in turn relaxes its pull on the Lens. The +Lens thereon becomes more convex. As age advances the Lens loses this +power and so the sight fails for near vision. + +] + +Thirdly, there is the so-called ‘near sight’. In this state near +objects can be clearly seen, but vision fails with those that are more +distant. Near sight is usually an acquired condition. The eye is too +long along the axis _xy_ (Fig 131). The resulting optical error can be +remedied by the use of concave spectacle lenses. + +Fourthly, there is ‘irregular sight,’ known as ‘astigmatism’. In +extreme cases of this condition no perfectly clear image can be +formed of any object, whatever its distance. It is in some measure +both congenital and acquired, and is due to an irregular deformation +of the optical apparatus of the eye. The remedy for astigmatism is a +compensatory deformation of the spectacle lens, which may need, in +other respects, to accord to the convex or concave form, according as +the deformation of the eye is of the far-sighted or near-sighted type. + +Historically optical errors of the eye were relieved by spectacles +before the nature of the defects was understood. The first suggestion +of the use of convex lenses as an aid to old sight was made by Roger +Bacon (1214-94) in the thirteenth century. Spectacles with convex +lenses for old or for far sight first came into use about 1300. By the +fifteenth century they were widely known. It may well be that their +adoption, by prolonging reading life, had an important effect upon +that process of extension of knowledge that we dub the ‘Revival of +Learning’. Concave lenses for the relief of near sight came in towards +the end of the fifteenth century, but were not widely used till the +eighteenth century. Astigmatic lenses were not contrived till well into +the nineteenth century. + +In 1874 S. Weir Mitchell (1830-1914), a very able American physician, +showed that the eye strain resulting from astigmatism was associated +with many nervous conditions. Weir Mitchell’s name is familiarly +associated with a line of treatment of these conditions. Since his +discovery it has been the practice to examine for optical error all +sufferers with headache and other neurotic symptoms. + +For long there was no means of estimating the degree of error, whether +of old sight, far sight, or near sight, save by trial on the part of +the patient himself. Spectacles were a common object of the hawker’s +trays, and from them the sufferer selected the specimen that suited him +best. The first essential improvement in this state of affairs was an +elucidation of the mode of action of lenses. The paths of light rays in +their passage through a lens were first correctly determined at the +beginning of the seventeenth century by the astronomer Johannes Kepler +(1571-1630). Knowledge of optics advanced during the seventeenth and +eighteenth centuries, but the optical errors of the living eye were not +accurately estimated until the time of the great Dutch ophthalmologist +Frans Cornelis Donders (1818-89). The system of prescribing and fitting +spectacles that is now in vogue dates from the publication of his +work, _The Anomalies of Refraction and Accommodation_, in 1864. Hardly +less important was the invention of the ophthalmoscope by Hermann von +Helmholtz (p. 213). Very important also was the introduction of ‘test +types’ for examining errors of vision by the Dutch ophthalmologist +Hermann Snellen (1834-1904). + +One of the most remarkable minds that has ever applied itself to +medical problems was that of the Quaker physician Thomas Young +(1773-1829). He was a man of immense learning, and is remembered +for having been the first to decipher Egyptian hieroglyphics. Young +explained the power of the eye to ‘accommodate’ for near vision. This +faculty of ‘accommodation’ was, he showed, due to changes in the +curvature of the crystalline lens (Fig. 132). In his memoir _On the +Mechanism of the Eye_ (1801), Young gave the first scientific account +of Astigmatism. His theory of color vision and his doctrine that light +is due to waves in the ether are still important. His ‘wave theory’ +of light completely replaced the old view, the so-called ‘emission +theory,’ that light is due to something material which goes forth from +the luminous object. While we are referring to Young we may remind +the reader that his work on ‘Energy’ lies at the back of all modern +Physics, in the history of which he takes an extremely important place. + +The operative treatment of the eye is of great antiquity. The most +important operative procedure is that for ‘cataract,’ a condition +caused by an opacity of the lens. ‘Couching’ for cataract, that is +depressing the opaque lens, was practised by Alexandrian surgeons +in the third century B.C. It is described by Celsus (p. 43) in the +first and mentioned by Galen (p. 50) in the second Christian century. +Contemporary with these authors are descriptions of the actual +extraction of the lens affected with cataract. + +In Imperial Roman times there were surgeons who devoted themselves +exclusively to cataract operations. These were practised during the +Middle Ages by the Arabs and to a less extent by the Westerns. For the +most part the operations were performed by wandering quacks, who were, +however, often very skilful. In the sixteenth century operations on the +eye began to pass into the hands of recognized medical practitioners. +The advances in the knowledge of the anatomy and physiology of the eye +in the eighteenth century enabled the French surgeon Jacques Daviel +(1696-1762) to explain the real nature of cataract, which is usually +nothing but a senile change in the lens of the eye. His knowledge made +it possible for him greatly to improve the operation for extraction, so +that, over a large range of cases, he had only 11 per cent. of failures. + +The modern era of ophthalmic surgery was ushered in by Donders (p. +319), von Helmholtz (pp. 213 and 319), and Albrecht von Graefe +(1828-70). The last was a professor at Berlin who greatly improved the +operation for cataract and introduced or improved many other important +operations on the eye. He was one of the first to make important +clinical observations with the ophthalmoscope, and he showed how the +instrument may be made to yield information not only of the condition +of the eye itself, but also of the brain and of its membranes, an +application which has become of the greatest value in later medical +developments. Though he died before the most important work of Pasteur +and Lister had become generally accepted, von Graefe was yet practising +a system of surgery which was not far from aseptic. + +As with most departments of Medicine, so also with Ophthalmology, +the most significant advances during the last generation have been +in the direction of prevention rather than cure. Prominent among +these measures are, firstly, school inspection with the consequent +early detection and isolation of infectious cases of conjunctivitis; +secondly, maternity welfare accompanied by prompt notification and +treatment of the very dangerous and sight-destroying ‘Ophthalmia of the +New-born’; thirdly, improved light regulation in factories and schools; +and, fourthly, adequate provision of spectacles for school children +with errors of vision. + +The recognition of the infectious character of the very chronic +and sight-destroying disease known as _Trachoma_, or ‘Granular +Conjunctivitis,’ has been of great importance for the Public Health. +The disease is common in the near East and in Eastern Europe and by no +means rare in slum quarters in the West. A rigid system of inspection +of immigrants, together with quarantine combined with treatment, has +done much to diminish its ravages in the United States. + + +§ 20. _Investigation of the Nature and Action of Drugs._ + + +(a) _Entry of Vegetable Drugs into the Pharmacopoeia._ + +An examination of the list of drugs that are in use at the present +day--apart from those which have been introduced by the scientific +movement of the last generation--yields some surprising results. Some +thirty per cent. of the crude vegetable drugs in the modern official +Pharmacopoeia were known in remote antiquity. The Egyptian medical +papyri mention, among others, Aloes, Caraway, Castor Oil, Coriander, +Dill, Fennel, Juniper, Mint, Myrrh, and Turpentine. Among Egyptian +mineral remedies still in use are salts of copper and of lead. Assyrian +medical tablets refer to most of the Egyptian drugs as well as to a +number of others, among which are Almond Oil, Aniseed, Galbanum, and +Liquorice. Among Assyrian mineral remedies that are used by us to this +day are Alum and Bitumen. Early Indian medicine had a very copious +pharmacopoeia. _Cannabis indica_, known as ‘Hashish’ or ‘Indian hemp’, +Cardamoms, _Cassia fistula_, _Datura stramonium_, and _Nux vomica_ are +among the valuable Indian herbs now in use in scientific medicine, +while Mercury preparations were perhaps ultimately of Indian origin. + +The medical herb lore of the Greeks comes to us chiefly from +Dioscorides (p. 43), who mentions about five hundred plants. A large +number of these are still in our own Pharmacopoeia. Among these, +besides those of Egyptian, Assyrian, and Indian origin, are Ammoniacum, +Belladonna, Camomile, Catechu, Cinnamon, Colchicum, Colocynth, Crocus, +Galls, Gentian, Ginger, Hyoscyamus, Lavender, Linseed, Male Fern, +Mallow, Marjoram, Mustard, Poppy, Rhubarb, Sesame, Stavesacre, Storax, +Terebinth, Tragacanth, and Wormwood. About thirty-seven per cent. of +our Pharmacopoeia was known to the later Greeks. From them the Arabs +derived, adding, however, enormously to their drug-lists, so that we +may say that about fifty per cent. of our drugs were in use by the +Arabic-speaking physicians of the Middle Ages. With the discovery of +America further important additions were made. Of these we have already +discussed the introduction of Cinchona, Ipecacuanha, and Tobacco (p. +95). Few important additions were made in the eighteenth century, +though among them was Digitalis (p. 328). + + +(b) _Active Principles._ + +One of the things that separate the practice of Medicine of our time +from that of previous ages is our power to give drugs in ‘pure’ form. +This means not only that we can secure drugs without adulteration, but +also that the active substances in drugs can be chemically isolated +and given without admixture. Most drugs used in Medicine are, in fact, +of vegetable origin. The possibility of giving them in chemically pure +form depends upon the discovery, early in the nineteenth century, that +plants owe their poisonous and remedial properties to small quantities +of _Active Principles_, which are susceptible of chemical extraction +and isolation. Thus the science that deals with the action and nature +of drugs, _Pharmacology_, really took its rise about a hundred years +ago, though many had experimented with drugs at an earlier date. + +Further progress in the same direction has been made by the so-called +‘synthetic’ preparation of drugs. Certain substances of vegetable +origin do not readily yield their active principles and to extract them +very complex chemical processes may be involved. There are special +obstacles to the complete purification of other drugs, even when they +have been obtained in a relatively pure state. These difficulties can +sometimes be surmounted by the preparation of the drug from inorganic +materials. This synthetic process of preparation is now possible for +many substances that are of medical application. Furthermore, when +a drug can be thus synthetically prepared, it is often possible to +try chemical variants upon it, and thus to obtain a more effective +preparation. + +In former times a vast number of drugs were habitually employed +by physicians, and they were often given in very complicated +prescriptions. ‘Polypharmacy’, the giving of many drugs, is a vice +from which Medicine has now in large part freed itself. The number of +drugs given by scientific physicians is far fewer that it was. For +this there are several reasons. Firstly, many drugs were found useless +for the purpose for which they were administered, and were at times +even dangerous. Secondly, since attention has been drawn to the active +principles of drugs rather than to the crude natural drugs, it has been +seen that, in fact, many of the drugs that were being given were merely +duplicates one of another, and that often the administration of the +active principle itself was more effective and more reliable than that +of the source from which it was obtained. + +What then is the nature of the drugs now being administered by +scientific physicians? They fall into a number of classes. The nature +and action of some of these is so simple that no prolonged discussion +of them is necessary. There are, for instance, the inorganic acids +and alkalis, the primary action of which, when taken internally, +can be determined by a series of experiments on gastric juice in a +test-tube kept at body temperature. Again, there are soluble inorganic +salts, which are absorbed unchanged from the alimentary canal. These +have the effect of increasing secretions. Their purgative effect is +well known, though the physiological details of their action are not +yet clear. There are yet other substances, such as metallic Mercury +in ‘grey powder’ or Bismuth, which act mechanically, even when +administered internally. Over and above these simpler substances, and +in addition to the traditional vegetable substances which have been in +use as medicines for centuries, there are others which have only been +accessible during the last few generations. We have already discussed +under separate headings the derivatives from animal glands, such as +of the Thyroid (p. 305), of the Adrenals (p. 307), or of the Pancreas +(p. 306), as well as the bacterial Vaccines (p. 261) and Antitoxins +(p. 267). We now turn to pure chemical substances of vegetable origin. +Of these mention may be made especially of the groups known as the +_Alkaloids_ and the _Glucosides_. + + +(c) _The Alkaloids._ + +By ‘Alkaloid’ is understood a nitrogenous substance, usually of +vegetable origin, which forms salts with acids. The alkaloids are +mainly obtained from the dicotyledonous plants. Generally they occur +in nature in combination with plant acids such as citric or tartaric +acid. The alkaloid group contains some of the most important drugs that +we possess. Among them are Morphine, Strychnine, Cocaine, Atropine, and +Quinine. + +The investigation of the alkaloids began with the nineteenth century. +Morphine was isolated from Opium by the Parisian apothecary Charles +Derosne (1780-1846) in 1803. He failed, however, to recognize its +chemical affinities, which were first grasped by the German apothecary +Adolf Sertürner (1783-1841). Their work, however, attracted but +little notice until attention was drawn to it by the great French +chemist Joseph Gay-Lussac (1778-1850), in 1817. The result was the +concentration of much scientific ability on the alkaloids. Prominent +among the early investigators were the French pharmacologists Pierre +Joseph Pelletier (1788-1842) and Joseph Caventou (1795-1878). Between +1818 and 1820 they isolated from Cinchona (p. 95) certain alkaloids +allied to Quinine, from Nux vomica the alkaloid Strychnine and certain +of its allies, and from Coffee the alkaloid Caffeine. Pelletier +in conjunction with the distinguished chemist Jean-Baptiste Dumas +(1800-84) followed this by a quantitative examination of a number of +alkaloids in 1823. The first alkaloid to be used as such in medicine +was Strychnine. It was introduced in 1821 by the French physiologist +François Magendie (1783-1855), the teacher of Claude Bernard. + +In the thirties and forties of the nineteenth century Liebig, who had +developed his doctrine of radicles (p. 206), attempted to determine +the formula of alkaloids. He was followed by Wöhler (p. 206). Since +then an immense amount of work has been done in investigating the +chemical nature and physiological action of alkaloids. The general +result has been to reveal the fact that each alkaloid-yielding plant +contains not one but a number of alkaloids. Those from the same plant +often have similar but not identical action upon the animal body. The +differences in physiological action of allied alkaloids have occupied +much of the attention of pharmacologists. The accurate knowledge of +these differences has made possible a far greater finesse in the +administration of alkaloid drugs than was previously possible. Some +alkaloids can be prepared synthetically, but the process is mostly of +theoretical rather than practical importance. + + +(d) _The Glucosides._ + +The Glucosides are an ill-defined group which have in common the +property of yielding a sugar-like substance--usually glucose itself--as +a result of certain chemical processes. They are mostly of vegetable +origin and the history of their investigation has been parallel with +that of the alkaloids. The first glucoside to be isolated was Salicin, +which was obtained from willows in 1819. It is the active principle of +the very ancient remedy for rheumatism, ‘Oil of Wintergreen’. Salicylic +acid was introduced into Internal Medicine in 1873 and its derivative, +Aspirin, in 1899. Both drugs are of great importance, and many other +derivatives of Salicin are in use. Salicin and its derivatives can +be prepared synthetically, and the synthetic products are in use in +Medicine. + +Of all the glucoside-yielding plants, perhaps medically the most +important is the Foxglove, _Digitalis purpurea_. The use of the plant +was known to some of the medieval herbalists, and is, moreover, +recommended in the German and English printed herbals of the sixteenth +and seventeenth centuries. Foxglove is mentioned as a folk remedy +in George Eliot’s _Silas Marner_, the story of which refers to a +period round about 1750 before the Industrial Revolution, ‘when the +spinning-wheels still hummed busily in the farm-houses’ (Fig. 89). It +was introduced into scientific Medicine in 1785 by William Withering +(1741-99) of Birmingham in his _Account of the Foxglove_, which gives +details of numerous cases treated with it. + +Digitalis long resisted the attempts to extract an active principle, +but since the seventies it has yielded to investigators a whole series +of glucosides. Digitalis and its derivatives have become of much +importance, especially in the treatment of cardiac conditions. Despite +the success in obtaining glucosides from the Foxglove, the extract of +the plant itself continues in wide use. + + +(e) _The Study of Pharmacology._ + +Since the middle of the nineteenth century the investigation of the +physiological action of drugs has been mainly in German hands. The +most prominent exponents of the method have been Karl Binz (1832-1912) +and Oswald Schmiedeberg (1834-1921), both professors at Dorpat, where +there has been a pharmacological laboratory since 1849. The first +pharmacological laboratory in America, that at Ann Arbor established in +1893, and the first in England, that at University College, London, +established in 1905, were successively occupied by A. R. Cushny +(1866-1926). The work of these and of other pharmacologists has not +tended to increase but to reduce the number of drugs. Nevertheless, +some new drugs of great importance have been introduced by them. Of +these, among the more valuable is Amyl nitrite, the inhalation of which +was first recommended by T. Lauder Brunton (1844-1916) as early as 1867 +as a remedy in certain cases of sudden heart seizure. + +Improvements have been made not only in the drugs themselves but +also in modes of administration. The ancient methods of inunction +and inhalation, as well as other older methods, have been greatly +elaborated in modern times, and are now of wider application than +they were. No advance of this order compares in importance with the +introduction of the Hypodermic Syringe by the ingenious French surgeon +Charles Gabriel Pravaz (1791-1853). By means of this instrument various +drugs can be injected directly into the subcutaneous tissues or into +the veins. This mode of administration is more accurate and under +better control than any other, and the action of the drug so injected +is swifter and more sure. + + +(f) _Chemotherapy._ + +During the twentieth century the outlook on drug treatment has +been modified by the success obtained in the _specific_ treatment +of certain diseases, that is to say, treatment by remedies which +strike at a particular disease and no other. Until quite recently +scientific Medicine recognized very few specific remedies. It had been +ascertained that Cinchona owes its value in Malaria to the alkaloid +Quinine (p. 326), which acts as a specific exterminator of the malaria +parasites, and not simply as a remedy for fever in general. It had +also been ascertained that Ipecacuanha owes its value in tropical +Dysentery to the alkaloid Emetine, which acts similarly as a specific +exterminator of the protozoal organisms which are the infective agents. +Quinine and its allied alkaloids and Emetine and its allied alkaloids +were practically the only specifics the value of which had been +scientifically proved, except Mercury for Syphilis. + +About the beginning of the twentieth century arose the new +‘Chemotherapeutic’ movement as it came to be called. This movement was +initiated by the studies of natural Antibodies (p. 262) by Paul Ehrlich +of Frankfurt (1854-1915). Antibodies are strongly antagonistic to the +parasitic organism the toxin of which has elicited them, but, on the +other hand, they are quite harmless to the animal body in which they +reside. Here are ideal remedies provided by Nature herself. Ehrlich +compared them to magic bullets, constrained by a charm to fly straight +at their objective and to injure no other. No such perfect artificial +drugs have yet been produced. The problem of Chemotherapy is rather how +to poison the parasite as much as possible while poisoning the host as +little as possible. + +When Ehrlich began the study of Chemotherapy observers had long known +that certain aniline dyes have a special affinity for certain cells +or organisms. Indeed the affinity of certain of the dyes for certain +bacteria had made possible the work of Koch on Tuberculosis and on +other diseases. As far back as the seventies and eighties much +work had been done on the subject, and the action of these dyes had +interested a large variety of investigators. Ehrlich’s first results +were on a protozoal parasite, which infests dogs. By injecting small +doses of a certain aniline dye into the veins of the infected animal +it was found possible to destroy the parasites while doing very little +injury to the dog. + +[Illustration: + +FIG. 133. THE ORGANISMS OF SYPHILIS IN A SMEAR FROM THE LOCAL +INFECTION. Highly magnified. They are best seen by means of a special +optical arrangement in which the outlines of the objects appear +glistening white and the background black. The round objects are pus +corpuscles, the two spiral objects the organisms of syphilis. ] + +At this point Ehrlich turned aside from the aniline dyes to study +the effects of much more toxic substances. He selected the compounds +of arsenic for the purpose. After prolonged research, he obtained an +arsenical derivative which proved very toxic to parasitic protozoa and +little toxic to their animal hosts. When a vast number of experiments +had been made, this substance was tried in 1910 in cases of human +Syphilis. This disease had been shown by Fritz Schaudinn (1871-1906) +in 1905 to be due to a protozoal parasite, the _Spirochaeta pallida_ +(Fig. 133). The results obtained by the new remedy were very +satisfactory and a valuable specific was thus added to the medical +armory. The drug became widely known as 606, since this is its number +in the series of the arsenic derivatives with which Ehrlich had +experimented. In the meantime others had been at work along lines +suggested by the aniline experiments. Their investigations led in 1920 +to the discovery of a specific against the deadly _Sleeping Sickness_ +or _Negro Lethargy_. This drug is known as _Bayer 205_ from the firm +that prepared it and the number in the series of substances that were +tested. + +Since the first preparation of 606 and 205 some interesting facts have +emerged concerning their action as well as the action of Quinine, +Emetine, and other specific remedies. It has been found that the +toxicity of these substances to the parasites against which they are +aimed is much greater when the parasites are within the body than when +the drugs are applied to the organisms outside the body. In other +words, the drugs do something to the body, or the body does something +to the drugs, that is inimical to the parasite. The nature of that +something is still under discussion. In the case of Quinine it seems +that the Quinine so affects the red blood corpuscles that the malarial +parasites cannot enter them and so cannot go through their sexual +cycle (Fig. 123). Thus the Quinine does not act as a direct poison +but attacks the parasite in a much more subtle manner. In the case +of other parasites the action of the specifics is more difficult to +understand. It should be pointed out, however, that the chief victories +of Chemotherapy have been in dealing with the protozoal rather +than the bacterial diseases. A main task of future Medicine will be +the discovery of means of eliciting antibodies against the various +bacterial infections. For this there is more immediate hope from the +use of remedies of vital origin than from those synthetically produced. + + +§ 21. _Interpretation of Collective Medical Data._ + +The drawing of a deduction of scientific value from experience is +by no means a simple process. In many sciences the investigator has +the power to control experience; in other words he can _experiment_. +But even the interpretation of experiment needs special precautions. +The physical experimenter must, for instance, make sure that he has +but one ‘variable’. Thus, if examining the effects of pressure on +a gas, he must see that in raising or lowering pressure he is not +altering temperature, or if recording the effects of temperature he +must satisfy himself that he is eliminating those of pressure. In +experiments upon living things the limitation of the field of action to +one simple factor is often--perhaps always--impossible. The biological +investigator is therefore accustomed to accompany his experiment with +‘controls.’ Thus, if he wishes to ascertain the effect on the growth +of animals of feeding with milk that has been boiled, he must feed one +series of animals on unboiled milk while he is experimenting with a +series fed with the boiled milk. He must take steps to ensure that the +two series are similar as regards age, strength, size, &c., and that +the conditions under which they live are identical, except as regards +the one factor the results of which he seeks to ascertain. + +When the observer is dealing with human material, it is very seldom +that he can either restrict the number of variables to one or secure an +adequate series of controls. Physicians are habitually in a position in +which action of some kind is demanded. They cannot await the conclusion +of laboratory researches, which may extend over years, for the patient +must be relieved at once or die. Being often unable to use those most +reliable instruments of science, experiment or observation under +control conditions, physicians have come to rely on what is called ‘a +general experience of disease’. + +One of the commonest fallacies of such general experience is assignment +of causative relationship between two conditions, simply on the ground +that they frequently occur in association. Thus it is a fact--and one +to which attention has been drawn by medical observers--that rheumatic +affections and red-headedness are often found together. But both +conditions are common and it has not been satisfactorily demonstrated +that the association of the two is any commoner than their frequency +in the population at large would render probable. Such general +experience is therefore very fallible and is incapable of scientific +expression, though it is often very valuable and sometimes indeed +entirely indispensable. To give such experience scientific expression, +to place it in terms of the ‘primary qualities’ of the founders of +modern Science (pp. 106-7), it is necessary to put it into statistical +form. Statistical statement thus becomes of the highest importance +for medical progress. Medical statistics, when prepared from proper +material and drawn up with the requisite skill, are at once the most +exact and the most generalized expression of medical experience. + +[Illustration: + +FIG. 134. DIAGRAM ILLUSTRATING THE ALTERATION IN THE PERCENTAGE OF +AGE-DISTRIBUTION OF THE POPULATION OF ENGLAND AND WALES FROM 1891 TO +1926. It will be observed that the people of England and Wales have +been getting steadily older. ] + +Statistical statements, however, vary greatly in their value and ease +of interpretation. The simplest statistical statements with which the +medical man has to deal are perhaps those which relate to surgical +operations. The categories in which the patient may be placed are here +limited; he may die, recover, improve, or get worse. If the operation +is a quite simple one, and if the surgeon is perfectly honest, and +also--which is rarer--quite unbiased, a small body of statistics +may carry immediate conviction as to the value of an operation. +Thus, Lister’s first results with amputation, as obtained under +his antiseptic conditions, at once satisfy the mind, although the +conclusions are based on only forty cases (p. 240). No surgeon at once +both able and willing to appreciate these results would hesitate to +adopt the new method. + +The operation of amputation is, however, in a statistical sense, +a particularly simple matter. The patient must either undergo the +operation or not, and the proportion of cases in which the necessity is +doubtful is very small. Further, he either recovers or dies--for the +operation could hardly be in itself unsuccessful, nor the surgeon in +doubt as to whether the patient had recovered or not. Many operations, +however, are not of this order. They may be performed for conditions as +to the exact nature of which the surgeon is uncertain, and for symptoms +which may be only partially relieved. Thus, the removal of the appendix +for Appendicitis may be most urgently necessary for the saving of life +in one case and may be a matter of convenience for the relief of more +or less indefinite symptoms in another. Further, what one surgeon calls +appendicitis another may not. One surgeon may have every appendix +that he removes submitted to skilled pathological examination before +he accepts the case as one of appendicitis and places it among his +statistics. Another may be quite content with naked-eye appearances of +the nature of which he alone is witness, judge, and reporter. It is, +therefore, clear that any collective statement as to the results of +such an operation must be cautiously scrutinized before conclusions of +the slightest scientific value can be drawn from them. + +[Illustration: + +FIG. 135. DEATH-RATE FROM CANCER OF THE TONGUE. It will be observed +that it is not a common cause of death till about 45 years of age, +but that it then increases rapidly to fall again in both sexes in old +age. These features are clearly related to various factors in the +causation of the condition. One of these is certainly Syphilis, which +is most frequently contracted between 20 and 30 and more often by men +than women. The so-called ‘tertiary’ effects of this condition, some +of which lead to Cancer of the Tongue, do not usually make themselves +felt, however, for many years after infection. Contrast Fig. 136 and +Fig. 137. ] + +There is a common and rather foolish saying that ‘Statistics may be +made to prove anything’. This is true, but it is true only in the sense +that _evidence_ may be made to prove anything. The matter turns on the +questions, firstly whether the evidence is of a good or a bad order, +and secondly whether the investigator is in a good or bad position to +interpret the evidence. A statistical statement may be well or ill +founded and well or ill interpreted, but statistical statement is, in +fact, the only scientific method open to us for presenting long series +of data. The conclusions to be drawn from those data, though sometimes +evident and easily elicited, at other times demand specially skilled +and specially trained interpreters. Moreover, to be of value to others, +such interpreters must also be skilled in expression, so that the main +body of those who have no statistical training may be in a position to +understand the essential elements in their conclusions. In no medical +department is literary power of greater importance than in that which +deals with statistics. Thus has arisen the small but highly important +class of medical statisticians. The rise of medical statistics into a +vocation places the crown on Medicine _as a science_. It is not given +to many medical men to be proficient in this department. But the duty +lies on all medical men, and indeed on all citizens, to appreciate +the value of this study and to seek to appraise its simpler and more +established conclusions. + +It is remarkable how frequently a straightforward statistical statement +may remove a false impression, even when the impression is based on +evidence not of a wholly unscientific character. + +[Illustration: + +FIG. 136. DEATH-RATE FROM CANCER OF THE LIP. It will be observed that +this curve resembles in form that of the death-rate from Cerebral +Haemorrhage as shown in Fig. 137, but differs from that of the +death-rate from Cancer of the Tongue as shown in Fig. 135. The chances +of dying from Cancer of the Lip are negligible till middle age is past +and then increase progressively throughout life. In the causation of +Cancer of the Lip Syphilis is not an important factor. On the other +hand the continuous irritation of pipe-smoking, which acts not at one +age but throughout life, has to be considered as a causative element. +Hence the resemblance to Fig. 137 rather than to Fig. 135. ] + +[Illustration: + +FIG. 137. CHART OF DEATH-RATE FROM CEREBRAL HAEMORRHAGE AND ALLIED +STATES. These conditions are extremely rare in the young, but among +the commonest causes of death in later life. The liability to them +increases progressively to extreme old age. This is explained by the +fact that Cerebral Haemorrhage, etc. follows on the rupture of a +blood-vessel in the brain and the rupture of the vessel is conditioned +by the hardness and brittleness of its coat. The hardness of the +arteries increases progressively in later life, whence the saying ‘a +man is as old as his arteries’. + +] + +For example the increase in the incidence of deaths from Cancer has +often been emphasized. But Cancer is a disease of advancing life. The +age distribution of the death-rate from many forms of Cancer is closely +parallel to that of certain other forms of senile disease (Figs. +136 and 137). Now the age constitution of the population of most civilized +countries is altering in the sense that the proportion of the elderly +and aged is constantly increasing (Fig. 134), so that some increase in +the Cancer incidence must be expected. Moreover the appearance of some +increase in the incidence of Cancer is due to improved diagnosis. How +far there is a real increase, when these factors have been taken into +account, is still somewhat doubtful. It must always be borne in mind +that a relative decrease in the proportion of deaths from _any_ cause +must automatically increase the proportion of deaths from other causes. + +Again, there is no doubt of the fall in the death-rate in England +and Wales from ‘Phthisis,’ or pulmonary tuberculosis, during the last +fifty or sixty years. There is also no doubt of the effect both of +bad housing and of urban conditions in inducing a susceptibility to +chest disease in general and to pulmonary tuberculosis in particular. +Further, there is no doubt that the rural population suffers less +from pulmonary tuberculosis than the town population. These matters +of common medical knowledge have naturally led to the conclusion that +the rise of the great towns has led to a great increase of pulmonary +tuberculosis, and that this increase has been remedied by the improved +housing and sanitary conditions of the last generation. A study of the +statistical evidence, however, negatives this view. The rise in the +proportion of deaths from pulmonary tuberculosis took place before the +Industrial Revolution. Moreover, the proportion began to fall long +before the campaign against tuberculosis could affect the issue. The +history of pulmonary tuberculosis may, in fact, be regarded as that of +an ‘epidemic’ outbreak, extending over about 100 years, of a disease +which has always been endemic and remains so now that the epidemic is +past. + +[Illustration: + +FIG. 138. CURVE SHOWING PERCENTAGE OF DEATHS FROM PHTHISIS to total +deaths from all causes in London over a period of 200 years. It will be +seen that the percentage begins to rise definitely about 1730 and to +fall definitely about 1830. This state of affairs may be pictured as an +epidemic lasting about 100 years. ] + +These points are well brought out in the accompanying diagram (Fig. +138). The fall in the proportion of deaths from Phthisis expressed +there gives rise to further considerations. It might seem that the +statement that the proportion of those who died from phthisis was +diminishing left in itself no doubt that the disease was less prevalent +than formerly. This, however, is not the case. Phthisis is more liable +to affect those under forty-five years of age than those who are +older. Now the proportion of the population that is under forty-five +is steadily diminishing (Fig. 134). This is one of the results of the +steadily diminishing general death-rate (Fig. 96, p. 196). Therefore +the proportion of the more susceptible to the less susceptible is +diminishing. It might have been the case (though it is not) that the +ratio (more susceptibles)/(less susceptibles) was not only decreasing +but was actually decreasing more rapidly than the ratio (total +deaths)/(deaths from phthisis). Had this been so, the conclusion would +have been justifiable that the fall in the proportion of deaths from +the disease did not correspond to any decrease in its infectivity. In +fact, however, the prolonged high mortality from phthisis and its later +rate of fall do suggest the former prevalence of a more virulent type +of the disease over a long period, in other words something of the +nature of a prolonged epidemic. + +This conclusion leads us to the conception of the nature of an +epidemic. To gain some conception of the ideas involved in that word, +we must glance back in history. + +From the time of Hippocrates onward the subject of Epidemic outbursts +of disease has drawn the attention of physicians. A writer in the +_Hippocratic Collection_ thought he could perceive an association +of symptom-complexes with each other and with the weather. In the +great work _Epidemics_, to which the name of the Father of Medicine +is attached, such a view, known as that of ‘Epidemic Constitutions,’ +is set forth. The view was revived by Sydenham in the seventeenth +century and has given rise to a vast literature extending to our own +time. In the eighteenth and nineteenth centuries the attempts of the +investigators of vital statistics to place the leading events of life +in a form capable of exact analysis (pp. 166-68) focused attention +on the search for a mathematical expression for the rise and fall of +epidemic diseases. + +The first successful attempt to describe epidemics along these lines +was made by William Farr (1807-1883), an official in the office of +the Registrar-General in London, and one of the greatest of all +epidemiological thinkers. His first publication on the subject was +in 1840, and had reference to the recent outbreak of small-pox, in +which more than 30,000 had died in England and Wales. It was his merit +to observe that the successive decreases in the number of cases in +successive equal periods during the decline of the epidemic correspond +to the successive increases in the number of cases during successive +equal periods of the rise of the epidemic. In other words, he observed +that the rise and decline of an epidemic tend to be mathematically +symmetrical. + +Farr’s suggestion that epidemics are liable to follow the lines of +regular mathematical rules drew little attention at the time, but in a +later year it led to a most remarkable and striking prophecy. At the +end of 1865 Cattle-plague broke out in England. Week by week the number +of cases increased. In the fourth week of February 1866 the responsible +Minister, in a speech in Parliament, gave a very gloomy account of +the state of affairs, expressing the belief that the devastation +would be far beyond what had yet been encountered. Farr, however, had +been watching the returns, and had been applying his rule to them. He +thereupon made a public pronouncement of his belief that at an early +date the outbreak would reach its maximum and would then decline. The +outbreak did, in fact, very closely follow the course which he had +predicted by reasoned calculation. Farr even prophesied the number of +cases that would occur week by week. His prophecy was near the truth. + +During the years that followed Farr’s prediction his views were applied +with success to a variety of epidemic conditions. The regular form of +the development of the epidemic was found to apply in certain outbreaks +of typhus, measles, and other conditions. + +Farr’s law was more exactly expressed by him in 1868. It remained, +however, simply a mathematical law, a rule of which the underlying +cause was not apparent. It was soon observed that his law applied to +many but by no means to all epidemics. Moreover, it was perceived that +the actual figures which he gave for his epidemic of 1840 resembled +those of certain other epidemics in that they could be fitted with +greater or less exactness to a well-known mathematically described +curve, known as the ‘normal curve of error’. We need not discuss the +mathematical foundation of this curve, which is shown in two variants +in Fig. 139. For our immediate purpose it is enough to observe that it +rises gradually at first, but then more steeply, that the steepness +decreases after a while, and then the curve begins to decline again, as +it rose. We note that it is symmetrical. + +[Illustration: + +FIG. 139. THE NORMAL CURVE OF ERROR, shown in two types made with the +same formula but with different constants. This curve has been shown +to be similar to that representing the incidence of cases in some +Epidemics. + +Vertical lines are drawn from two pairs of symmetrical points. The +continuous lines refer to the higher curve, the broken lines (from the +points of intersection of the two curves) refer to the lower curve. The +lines will be seen to divide the curves into three parts. This division +is of such a character that the sum of the two lateral areas is equal +to the central area for each case. ] + +[Illustration: + +FIG. 140. Curve of monthly number of deaths from Small-pox during an +epidemic at Warrington, Lancashire, in 1743. + +FIG. 141. Curve of weekly number of cases of Scarlet Fever registered +during an epidemic at Glasgow in 1892. + +Both curves are fitted to the theoretical epidemic curve, and are +modified from Brownlee. The curves are in both cases explained on the +assumption that the infectivity, having reached a high point at the +beginning of the outbreak, decreases thenceforward in geometrical +progression. ] + +When we are dealing with living beings or are dealing with things that +may indefinitely approximate to a mathematical rule, but never entirely +fit it. Especially when the living beings are also human beings, with +their infinitely complex relationships, various factors are present +which interfere with the exact application of mathematical findings. +Nevertheless, the theoretical form of the epidemic is an extremely +useful framework into which actual epidemics may often be fitted, with +greater or less exactness. In the accompanying figures (Figs. 140-141) +are adduced cases of greater exactness. There are, however, many cases +in which an ‘outbreak’ does not seem to fit the simple theoretical +curve at all. Examination of such curves has in some cases suggested +that we have not one epidemic or disease but two or more to deal with. +In some cases it has been possible to analyze the outbreak on the basis +of two or more theoretical curves, suggesting in fact two or more +outbreaks of similar but not identical causation (Fig. 142). + +[Illustration: + +FIG. 142. THE CURVES OF SOME EPIDEMICS, which do not follow the +theoretical curve, may be analyzed as compounded of two or more +epidemics, each of which accords individually to the mathematical rule. +Thus ‘Summer Diarrhoea’ is a seasonal disease very fatal to infants +in England during the hot months, July and August. The angular curve +shows the average daily incidence of deaths from this disease in London +during the fifty-three years 1850-1903. It can be analyzed into two of +the theoretical epidemic curves. + +Each reading of the curve, calculated from the actual cases of ‘Summer +Diarrhoea of Infants’, can be divided into two, as indicated in the +step-like readings, one dotted and the other continuous. These accord +beautifully with two theoretical curves, thus indicating not one but +two recurrent epidemics. It thus seems probable that two separate +sources of infection are confused as ‘Summer Diarrhoea of Infants’. + +] + +What can be the causative element which constrains the incidence of a +disease in a population to follow mathematical rules? An answer was +provided by John Brownlee (1868-1927), the late statistician to the +Medical Research Council of England. The leading fact about an Epidemic +is that it rises to a maximum, falls, and then dies out, and that the +curve representing the number of new cases in a series of equal and +consecutive periods of time throughout the Epidemic is symmetrical. In +practice the decline is usually a little slower than the rise. This +is sometimes, at least, due to better observation and record of the +later cases. Now why does an Epidemic die out? The possible reasons +may be reduced to three. Firstly, the end of an Epidemic may be due to +the exhaustion of susceptible persons in the population. That is to +say, all the survivors are immune, either being so by nature or having +become so by having contracted the disease and recovered. Secondly, it +is conceivable that the liability to the disease should be decreased, +not by rise in the proportion of immunes, but by externally acting +causes, as, for instance, by rise of seasonal temperature, which would +provide conditions under which the organism loses its infectivity. +Expressed in older language, this is to say that the ‘Epidemic +Constitution’ (p. 342) has changed. Thirdly, the infecting organisms +may, of their own inner nature, lose their infectivity. The second +factor may act in special cases, but may be disregarded except in those +cases. We are, therefore, left with the first and third. + +Now it is possible to construct curves that would correspond to the +exhaustion of the supply of susceptible persons by continuous increase +of the proportion of those who become immune either by taking the +disease or by dying. These curves, however, have the character that +their descent is more rapid (and neither as rapid nor less rapid) than +their ascent. It is the merit of Brownlee to have suggested that the +actual curve of the Epidemic corresponds to a known though very little +understood biological phenomenon, namely change in the infectivity of +the invading organisms. The simplest expression of his discovery is +that the loss of infectivity of these organisms is approximately in the +ratio given by a geometrical progression. That is, if the infectivity +of the Epidemic be _m_, and at the end of a unit of time _mg_ (when _g_ +is less than unity), at the end of a second unit of time it will be +_mg_^2, and at the end of the third _mg_^3, and so on. Assuming this +to be a fact, the course of Epidemics would follow the curve of normal +error (Fig. 139). + +Of late years it has been possible to institute artificial epidemics in +a series of animals under control conditions. Such experiments must, +in the nature of the case, cover a large number of years, but they bid +fair to throw much light on the nature and progress of human epidemics. + +These results seem to show, what was believed on other grounds, that +in the case of highly infective disease, to which, in any population, +there are many highly susceptible, isolation of declared cases has +little or no effect on the course of the Epidemic. Such diseases are +Scarlet Fever, Measles, Influenza, &c. Moreover, the experimental +epidemics seem to confirm the conclusions of Brownlee that in some +cases at least the course of the epidemic is determined by biological +changes within the parasitic beings that cause it. + +Thus in the end our health, our lives, and indeed the continuance +of our civilization may well depend upon a factor which is outside +ourselves. For reasons which we know not, the pullulating billions +of living things which are around us, upon us, within us, take up a +virulence which before they had not, and after a time they lose that +virulence to become as they were before. The world is devastated by +an outbreak of Plague, of Cholera, of Influenza. But how and why +the organisms that carry these diseases should acquire a new and +more deadly infectivity lies among the secrets yet locked within the +living cell. Life--the life of the Cell, of the Bacterium, of Man +himself--remains among the _Arcana Naturae_. These are the secret +things that in their essence--which is Life--remain and will remain +behind the veil. From such cells we came, through such cells we shall +return. As to what is the force which starts these processes on their +way, we are as ignorant as children, and must remain so, in essence, +till we understand the nature of the processes of coming into being and +passing away. So Medicine must end where she began, quaking before the +Mystery of Life, a Mystery which could only be resolved if we could +express Mind in terms simpler than itself. If this could be done the +veil that is cast over all flesh would indeed be rent. But the author +of this work believes that the hope of this is vain and that we are +here in the presence of one of the ultimate things. + + + + +EPILOGUE + + +We have now traced various movements in Medicine throughout the ages +and have seen how all the sciences in turn have been made to bring +their tribute to the alleviation of suffering. We have seen especially +how the consideration of disease as a whole, and of the health of +peoples as a whole, has introduced a new view in the handling of +disease. Health is a public asset, and its promotion has now been +recognized as a public duty. There are undeniable disadvantages in +placing officers of the State in control of the personal liberties of +its citizens, but, on the whole, the advantages, in matters of health, +have outweighed the disadvantages. Only a professed pessimist or a +crotchety reactionary could deny the gains to humanity from the passage +of preventive measures from private into public hands. + +There is another side of the picture which we have need also to +consider. The advances in Medicine and the advantages that have accrued +therefrom have been entirely the result of the application of the +rational method of observation and experiment. To control Nature we +must above all things understand Nature. Neither the conception of +Nature as the kind old nurse nor the conception of Nature ravening red +in tooth and claw will stand. Least of all can we tolerate the picture +of Nature as a bountiful mother. If we go to her asking something for +nothing, she (far from bountiful) will give us little but what we have +given her, and to him who but begs she gives no more than a beggar’s +portion. It is thus that she has served the magician and the wizard, +who think they can compel her to give them all things by their paltry +charms! + +The amount of human labor and ingenuity that is now being thrown +into the investigation of Nature is almost incredible even to men +of science. Some conception of the enormous and unreadable bulk of +scientific literature may be gained by a glance at the _International +Catalogue of Scientific Literature_. This gives the _titles alone_ +of original articles in the various departments of physical science. +These titles for the year 1914 alone occupied seventeen closely printed +volumes! The rate of publication has accelerated considerably since +then. There are now about 25,000 periodicals devoted to scientific +publications! There are very few departments of science which do not +have some bearing on Medicine. It is evident that no human mind can +possibly compass even a year’s output of this material. + +And yet it is not the bulk of writing on Science that forms the only +or even the chief deterrent to the general comprehension of its +principles. The mass of scientific detail has always been beyond the +power of one mind to grasp. But as we have traced Rational Medicine +through its long course in Antiquity and the Middle Ages to its +debouchment on to our own time, we have found not only a more difficult +but also a new situation. In approaching our own age we have found ever +more difficulty in discussing Rational Medicine as a single channel of +thought. It spreads into a Delta, of which, though the many mouths may +inosculate, yet the tendency seems to be for an ever wider divergence. +This diffusion, induced by increased specialization, cannot go on +for ever without defeating the very objects for which specialism was +invented. + +On the other hand, when we glance at the tasks now being performed by +the medical man, we cannot fail to be struck by the great increase +in the number of things that have come to be regarded as within his +sphere. It is a commonplace that he has in large part taken the place +of the parson. But he has also made encroachments on the functions of +the lawyer, the legislator and the judge, of the schoolmaster, the +architect and the statistician. He has assumed some of the duties of +the parent and guardian, while even the soldier and the policeman are +to some degree under his control. In the ordering of their lives, +and even in the regulation of their vices and the reform of their +shortcomings, men and women are far more willing to seek the advice and +help of the medical man than once they were. The reason is, without +doubt, that his advice is much more worth having than it once was. + +The organization of research, the systematized record of experience, +the improved intercommunications of our time, have combined to +increase vastly the medical man’s sources of information and to make +his application of them more accurate and more scientific. Moreover, +there are factors in our social life itself that have tended not only +to deepen the physician’s knowledge but to widen his experience. His +effective working-day has greatly lengthened. No doubt, the motor car +and railway train are important elements in this extension of the +doctor’s day, but a far more fundamental element is the advent of the +skilled nurse. Many tasks which occupied the time of the doctor in the +old days are now relegated to her. The result is that the doctor sees +a far greater number of patients and has a much greater experience of +actual sickness than was formerly possible. + +But after we have discussed all those factors which have gone to +the increase of the power of Physic we have still to consider the +philosophical basis which has conditioned this increase. Men do not +willingly accept that in which they do not believe. The shifting of +men’s trust implies a shifting in their faith. In truth the triumph +of Physic has underlying it a subtler triumph, that of Scientific +Determinism. The great increase in the detailed knowledge of Nature has +led to a great increase in the belief in the Reign of Law. Disease and +death were once thought to be the special acts of Providence. They are +now widely held to be illustrations of determined natural laws. Men +of science in general, and medical men in particular, are not wont to +profess themselves philosophers, but, in fact, much of their work is +done in a spirit which would have us believe that these determined laws +are universal and are wholly outside ourselves. Has there not arisen a +school that would claim that our thinking is but a seeming, and that +we do but behave as though we thought? Three centuries ago Descartes +conceived that the animal might be treated as a machine. If man be +but an animal, consequences are entailed from which Descartes shrank, +for the watchword of his philosophy was ‘Cogito, ergo sum’, _I think, +therefore I am_. There is a newer school whose work is intimately +bound up with the progress of Medicine that would abandon this basic +doctrine of the father of modern Philosophy, who is also the founder +of Physiology, as a separate discipline. + +The position as it stands appears as a dilemma. The triumphs of +Science have been secured by disregarding Mind, and yet they cannot be +appreciated or advanced without invoking Mind. Unless we accept the +full conclusions of the Determinist Philosophy, we are forced to the +conclusion that Mind must do something to the animal body. If Mind +holds the reins, there must be a point at which Mind pulls the reins. +The matter ever in dispute is where that point may be. If life and +growth are bound up with an Entelechy, as seems to the author of this +work to be the case, there must somewhere and somehow be a level in the +organism at which the laws of physics and chemistry are transcended by +some other mode of action. + +It is no part of our task to provide a Philosophy which will resolve +all the problems that our subject raises. Nevertheless, in the presence +of this dilemma, such a work should not close on too optimistic a note, +in the department either of medical thought or of its application. Even +if looked at merely as an interpreter of its own terms, determinist +thought, which lies at the basis of modern medical developments, has +not been quite so universally successful as is often supposed, and as +the preceding pages of this book may lead the reader to think. While +enormously increasing the sum of our knowledge of Nature, it has also +tended more and more to separate the parts of that knowledge from each +other. It is clear that no such way of thinking can ever give us a +survey of Nature as a whole. It can never enable us to ‘think things +together’, and without such thinking together our life is and must +remain a contradiction and a muddle. + +For a real survey of Nature we must look to another Philosophy and +another Method. We are in this matter but just entering on a new era, +and may it not be that some sort of solution will be provided by a +better study of the Mind itself? Only by our minds can we know that +Nature presents us with any order at all. It therefore behoves us to +search out most diligently all that we can learn about our minds, to +see whether, on the one hand, this determined order, which has so +impressed our age, is in any degree within us and part of our observing +instrument, or whether, on the other hand, it is wholly without us. +There is much evidence that it is not wholly without us, and that +Determinism is a habit in our method of thinking on certain topics, and +that the emphasis on the ‘primary qualities’ (see pages 106-8) which we +inherit from Galileo is by no means justified. It may be that what we +think and feel and see is not only as real as what we weigh and count +and measure, but that weighing, counting, and measuring are but forms +of thinking, feeling, and seeing. In this connection the reader should +turn over again in his mind the implications of the ‘Law of Specific +Nerve Energies’ enunciated by Johannes Müller (see pp. 212-13). + +Nor must we end on too optimistic a note as to the actual achievements +of Science. Advances in our knowledge have certainly been very great, +but they may be and often are exaggerated. We must always guard +ourselves against considering mere accumulation of detail as an +advance. The collection of data is but a means to an end, and if that +end is not reached they are a very weariness and vexation of the +philosophic spirit. Real advance in knowledge can only be tested by +effective advances in theory, and thus judged the cost of progress--the +cost in the brute accumulation of facts--has increased far more rapidly +than progress itself. What is wanted is not so much new data as +correlation in their accumulation. The increase in medical specialism +is not so much evidence of advance as it is of the heaping up of +uncoordinated observations. + +Works on Medicine intended for popular consumption are often couched +in the jubilant terms of victory. Yet there are whole departments in +which no progress whatever has been made. We pride ourselves on the +advance in knowledge of infectious disease which the germ theory has +brought us, and yet we are utterly and completely ignorant of the two +things about infectious disease which are the two things most worth +knowing on that topic. Firstly, no man has conceived the way in which +the parasites of disease first fastened themselves on the animal body, +a specific parasite to a specific animal. In other words, we have not +the least idea how diseases first begin. Secondly, no man has conceived +a reason why diseases, distributed over a wide area and in many bodies, +should vary in virulence from time to time, why, for instance a +relatively mild condition, such as influenza, should suddenly devastate +the world. It is easy to say that human resistance varies, but that is +only to restate the problem in terms of which we know nothing. On these +high topics of Medicine we know as much and as little as Hippocrates. + +Moreover, if we turn to definite diseases, there are many conditions, +and those among the most important, of which our ignorance is almost +complete. Thus of the very common and painful diseases, muscular +rheumatism and rheumatoid arthritis, we know hardly more than +Hippocrates and our remedies are but little more effective than his. +The common cold--economically the most important of all diseases, not +excluding Cancer and Tuberculosis--has a vast literature, but the +physician is almost helpless in its presence and can but let it run +its course. Measles, Whooping-cough, and Influenza have become more +deadly of late years. We have still no clear line of treatment for +them. Nor have we any real insight into the nature of Cancer. Those +who reach advanced age have no better chance of life than they had +two hundred years ago (p. 177). Above all, it must be remembered that +the great majority of deaths are caused by diseases theoretically +preventable. There is a natural term to life which it is desirable that +all should attain. Yet most of us will surely die a violent death as +truly as though struck down by a felon’s hand. Death from disease is an +unnatural and a violent death. + +Faced by facts of this order there are those who constantly urge +increased activity in medical ‘research’. But research can only be +prosecuted by those whose talents specially fit them for the work. +With reason it may be and is doubted whether there are many in Western +Europe or America who could profitably be employed on medical research +who are not already so employed. It is easy to make investigations +on a certain level, but those best qualified to judge are of opinion +that the general level of medical research has fallen, not risen, of +late years. The number of publications has multiplied manyfold, but +there are those who doubt if there is much increase in investigation of +the first order. The increase in specialism and the extremely narrow +outlook of some workers has stultified much investigation, since with +his decreased range the researcher is often less able to perceive the +bearings of his own work. Thus he may labor for years elaborating a +technique by means of which he may collect facts without that guiding +wisdom or judgment that is the mark of genius. It must ever be borne +in mind that the object of fact-collecting is the deduction of law. +Not all facts can be collected, for facts are infinite in number, and +it is therefore necessary to select. Selection involves _judgment_, +the final and indefinable property of Mind; for, if from the facts no +laws emerge, the facts themselves become an obstacle, not an aid, to +scientific advance. + +All who have to read systematically large masses of modern scientific +literature have been unfavorably impressed by its absence of form. It +is evident that a large proportion of scientific workers lack adequate +literary training and never acquire a proper sense of literary form. +The growing interest in Science has had an unfavorable effect on +Education in the direction of early and intensive specialization. The +result is that many scientific publications are but semi-literate, +they are often incoherent in presentation and even more frequently +unnecessarily diffuse. Nor is it merely a matter of form. Language is +but the outward and visible sign of which Thought is the inward and +spiritual reality. Confused writing usually indicates and always leads +to confused thinking. Thus the unliterary character of scientific +writing bids fair to pass from being a mere nuisance to become a great +scientific evil. Good and effective writing implies a broad and solid +literary background, just as good and effective scientific research +implies a broad and solid scientific background. The fact is that the +Humanities and the Sciences are far from being as independent of each +other as many suppose. If literary studies lead to clear and effective +expression and clear and effective thinking in the domain of Science, +scientific studies ventilate and inform and vitalize Literature. The +separation of the two disciplines, especially in the adolescent stage +of mental development, does an injury to both. The concentration of the +endowments of Learning on the scientific departments and especially on +the departments of applied science has given rise to a very widespread +evil which is none the less evil because it is subtle. + +Within the sphere of the specifically medical sciences themselves there +are tendencies which are open to somewhat similar criticism. + +The great fallacy from which scientific Medicine has suffered in the +past, and still to some extent suffers, is the ‘direct attack’. We +have come to look upon the animal organism as an immeasurably complex +machine. For its elucidation knowledge from the most diverse quarters +is therefore demanded. The physical chemist, the organic chemist, +the physicist, the mathematician, the protozoologist, the systematic +biologist, the botanist, the spectroscopist, the geologist, and a host +of others are following callings which have no obvious bearing on the +study of disease. Yet the results obtained by them, and by men of +science in many other departments, must be utilized in the study of +disease. Our knowledge of health and of disease thus depends on the +sciences as a whole--nay, on Knowledge as a whole. Those who would +promote the health of mankind would do well if they sought to encourage +not so much the medical sciences as Science as a whole, or rather +Learning as a whole, for Science is a way of life which may penetrate +into all departments of Learning, and is something far greater than +those discrete accumulations of knowledge that we call ‘the sciences’. +The Sciences, working out their destiny, must in the end come together +again. + +If that consummation be reached we may expect improvement in health and +prolongation of life to a degree greater than any previous ages have +seen. We may indeed expect something yet better, for we may hope for a +philosophy of the mind that shall make life better worth the living. + +Medicine cannot give immortality, but it should enable us all to live +out our full lives. Death, coming in due and not undue time, is shorn +of all his terrors, when every man and every woman + + Shall come to his grave in a full age, + Like as a shock of corn cometh in, in his season. + _Job_ v. 26. + +[Illustration: FRIENDLY DEATH] + + + + +INDEX + + + Abdominal Surgery, 243-8 + + Achondroplasia, 17 + + Adrenals, 325 + + Aesculapius (Asklepios), 4, 7, 8, 11, 49, 51 + + Ague, _see_ Malaria. + + Air, Nature of, 151-6 + + Air-Pump, Boyle’s, 125-6 + + Albinus, Bernard Siegfried (1697-1770), 140-1 + + Albucasis the Moor (11th cent.), 67, 70 + + Alchemy, 122-6 + + Alcoholism, 291 + + Alexander the Great, 27, 36 + + Alexandria, 52 + + Alexandrian School, 36-41 + + Alkaloids, 325-7 + + Almond Oil, 322 + + Aloes, 322 + + Alum, 322 + + American Civil War, 300 + + Ammoniacum, 322 + + Amputation, 240, 336 + + Amyl nitrite, 329 + + Anaerobic bacteria, 257 + + Anaesthesia, 162, 235-7 + + Analgesia, 237 + + Anatomy, 122, 138; + of Galen, 55-6; + Medieval, 72-6; + Renaissance, 82-92; + earlier 19th cent., 204; + Morbid, 156-9 + + Anatomy Act (1832), 193 + + Aneurysm, 166 + + Animal Spirit, 58 + + Animism, _see_ Nature-Worship + + Aniseed, 322 + + Ann Arbor, 328 + + Anthrax, 229-34, 250-1, 261 + + Antibodies, 262, 268-9, 330, 333 + + Antidiphtheritic serum, 264 + + Antirachitics, 312-13 + + Antiseptic Surgery, 235, 237-43. + + Antiseptics, 162 + + Antitoxins, 264-5, 325 + + Antoninus, Emperor, Statute of (160), 46 + + Apertorium, the, 164 + + Aphorisms, the, 256 + + Appendicitis, 336 + + Aqueducts, Roman, 46 + + Arabic Drugs, 323 + + Arabic Medicine, 66-8 + + Aricia, 12 + + Aristophanes, 29 + + Aristotle (384-322 B.C.), 1, 14, 27-35, 37, 69, 86 + + Arles, 42 + + Arsenic, 331 + + Asclepiades of Bithynia (d. _c._ 40 B.C.), 41-2 + + Aseptic Surgery, 235, 237-43 + + Asklepios, _see_ Aesculapius + + Aspirin, 327 + + Assyria, 6; + Medical Tablets in, 322 + + Astigmatism (Irregular Sight), 317-19 + + Astrology, 54 + + Astronomy, 103-5, 122, 135-6 + + Atomic Structure, 37, 126 + + Atropine, 326 + + Auenbrugger, Leopold (1722-1809), 160 + + Augustus, Emperor (reigned 27 B.C.-A.D. 14), 42 + + Aural Surgery, 188 + + Avicenna, the Persian (980-1036), 67, 70, 72, 74, 82, 180 + + Avignon, 76 + + + Babylonians, the, 6-7 + + Bacon, Roger (1214-84), 318 + + Bacteria, 120, 121, 227 + + Bacteriology, 249-53 + + Bacteriolysins, 269 + + Baer, Karl Ernst von (1792-1876), 204 + + Bagdad, 66 + + Baillie, Matthew (1761-1823), 158 + + Balfour, Francis Maitland (1851-82), 204 + + Bayer, 205, 332 + + Beaumont, William (1785-1853), 148 + + Bedlam, 286 + + Behring, Emil von (1854-1917), 264, 266 + + Bell, Sir Charles (1774-1842), 145, 207, 213 + + Belladonna, 322 + + Bentham, Jeremy (1748-1832), 178, 190-2, 192-3 + + Bergmann, Ernst von (1836-1907), 248 + + Beri-Beri, 272, 313 + + Berlin, 222, 230, 248, 321 + + Bernard, Claude (1813-78), 213-15, 229, 326 + + Bethlem Hospital, 286 + + Biggs, Hermann M., 202 + + Binz, Karl (1832-1912), 328 + + Biology, 132, 139 + + Bismuth, 325 + + Bitumen, 322 + + Black, Joseph (1728-99), 151-3 + + Black Death, the, 80-1 + + Blood, Circulation of, 111-20, 146 + + Blood-letting, 39 + + Blood-poisoning, 239 + + Blood-pump, mercurial, 218 + + Board of Health, 194-6 + + Boerhaave, Hermann (1668-1738), 122, 139-42, 151, 156-7, 169-70 + + Bologna, 71-4, 76, 116, 149 + + Bonn, 205, 222 + + Bordeaux, 42 + + Bordet, Jules (1870-), 269 + + Borelli, Giovanni Alfonso (1608-79), 39, 129-31 + + Boston, Mass., 198 + + Botany, 95-6, 138 + + Boyle, Robert (1627-91), 35, 101, 124-6, 151 + + Brahe, Tycho (1546-1601), 103, 135 + + Brain, Aristotle on, 29-30 + + Bretonneau, Pierre (1771-1862), 185, 253 + + Broca, Paul (1824-80), 211 + + Brownlee, John (1868-1927), 348-9 + + Bruce, David (1885-), 255 + + Bruno, Giordano (1548-1600), 102-3 + + Brunton, T. Lauder (1844-1916), 329 + + Brussels, 85 + + Bubonic Plague, 201 + + + Caesar, Julius (102-44 B.C.), 45, 46 + + Caesarean Section, 45 + + Caffeine, 326 + + Cambridge, 111, 311 + + Camomile, 322 + + Canada, 290 + + Cancers, 223-4, 337-9, 359 + + _Cannabis indica_, 322 + + Caraway, 322 + + Carbohydrates, 311 + + Carbolic Acid, 239-40 + + Carbon dioxide, 153, 155-6 + + Cardamoms, 322 + + Carpenter, Mary (1807-77), 300 + + Carrel, Alexis (1873-), 248 + + Carrier Problem, 269-70 + + _Cassia fistula_, 322 + + Castor Oil, 322 + + Cataract of the Eye, 320-1 + + Catechu, 322 + + Cattle-plague, 344 + + Cavendish, Henry (1731-1810), 153, 156 + + Caventou, Joseph (1795-1878), 326 + + Cell Theory, 219-24 + + Cellular Pathology, 219-24 + + Celsus, 43-4, 320 + + Census system, 168 + + Cerebral Haemorrhage, 338, 340 + + Cerebrospinal Meningitis, 269-70 + + Chadwick, Edwin (1800-90), 171, 178, 193-6, 202 + + Charcot, Jean Marie (1825-93), 211 + + Charles V, Emperor, 88 + + Chemotherapy, 329-33 + + Chester, 182 + + Cheyne-Stokes Respiration, 25-6 + + Chicago, 248 + + Child Life, 18th c., 180-1 + + Children in Factories, 191, 194 + + Chloroform, 235, 236 + + Cholera, 194-5, 198, 201, 234; + chicken, 234, 261 + + Cholestrol, 312-13 + + Christianity, 61-2 + + Chyle, 56 + + Cinchona, 95, 281-2, 323, 326, 330 + + Cinnamon, 323 + + Claudius, Emperor (reigned 41-54), 49 + + Cleopatra, 36, 41 + + Clinical Medicine, 100; + Methods and Instruments, 159-61; + Teaching, Rise of, 138-42 + + Clinical Thermometer, 159 + + Cloaca Maxima, 45 + + Cnidus, 8 + + Cocaine, 236-7, 326 + + Coffee, 326 + + Cohnheim, Julius (1839-84), 238 + + Colchicum, 323 + + Colocynth, 323 + + Constantine (d. 1087), 64-5 + + Constantinople, 183 + + Consumption, 234 + + Contagious Diseases in 19th cent., 201 + + Cook, James (1728-79), 170 + + Cope, E. D. (1840-97), 204 + + Copernicus, Nicholas (1473-1543), 88, 102 + + Coriander, 322 + + Corning, J. L. (1855-), 236 + + Cos, 8, 14 + + Cretinism, 304 + + Crile, G. W. (1864-), 237, 310-11 + + Crimean War (1854), 298 + + Crocus, 323 + + Curve of Error, 345-9 + + Cushing, Harvey (1869-), 236, 249 + + Cushny, A. R. (1866-1926), 329 + + Cuvier, Georges (1769-1832), 204 + + Cytology, 223 + + Cyto-Pathology, 223 + + + Darwin, Charles (1809-82), 204, 227, 293 + + _Datura stramonium_, 322 + + Daviel, J. (1696-1762), 320 + + de Baillou, Guillaume (1538-1616), 96, 98-9 + + de Chauliac, Guy (1300-68), 76-7 + + Delirium, early case of, 25 + + Dementia praecox, 292 + + Democritus (_c._ 400 B.C.), 37 + + Demography, 188 + + de Mondeville, Henri (_c._ 1270-1320), 72, 74 + + Dengue, 272 + + Derosne, Charles (1780-1846), 326 + + Descartes, René (1596-1650), 39, 103-4, 127-9, 207-8, 355 + + Diabetes, 306 + + Diarrhoea, 347 + + Diderot, D. (1713-84), 131 + + Digestion, 146-8, 214-15 + + Digitalis (Foxglove), 323, 328 + + Dill, 322 + + Dioscorides, 43, 322 + + Diphtheria, 24, 185, 201, 253; + immunization, 262-7 + + Dispensary Movement, 178, 180 + + Dix, Dorothea Lynde (1802-87), 290 + + Donders, Frans Cornelis (1818-89), 319, 320 + + Dorians, the, 4 + + Dorpat, 328 + + Drugs, 95, 322-33 + + Ductless Glands, 302-8 + + Dürer, A., 83 + + Düsseldorf, 50 + + Dumas, Jean-Baptiste (1800-84), 326 + + Dysentery, 271, 330 + + + Eberth, Karl Joseph (1835-1927), 258 + + Edinburgh, 235 + + Egyptian Civilization, 7 + + Egyptian Medical Papyri, 322 + + Ehrlich, Paul (1854-1915), 269, 330-1 + + Electricity, 149-51 + + Elements, the Four, 34, 124 + + Embryology, 30-2, 110, 117-18, 120-1, 204 + + Emetine, 330, 332 + + Emphysema, 158 + + _Encyclopédie_ (1751-72), 130 + + Endotoxins, 260, 266 + + Entelechy, ix, x, 33, 356 + + Epicurus (342-270 B.C.), 37 + + Epidaurus, 11 + + Epidemics, 182-5, 198, 200-1, 342-50 + + Epidemiology, 138 + + Epileptics, 292 + + Erasistratus of Chios (_c._ 300 B.C.), 36, 37-40 + + Erysipelas, 239 + + Esquirol, Jean Étienne D. (1772-1840), 288-9 + + Ether, 235, 237 + + Evolution, Organic, 27, 31 + + --, theory of, 204 + + Exotoxins, 260, 266 + + Experimental Medicine, 211-19 + + Eye, the, and its Disorders, 313-22 + + + Fabricius, Jerome, of Aquapendente (1537-1619), 109-11 + + ‘Far Sight’, 316-18 + + Farr, W. (1807-83), 343-5 + + Fat, 311 + + Federal Health Service, 200 + + Fennel, 322 + + Fermentation, 225-8, 230, 239 + + Ferrier, D. (1843-), 211 + + Fevers, 67, 101, 169, 171-2, 174, 185, 194, 200-1, 243, 254-5, 258-9; + _see also specific fevers_ (Malaria, Typhoid, Yellow, &c.) + + Fliedner, Frederica (1800-42), 297 + + Fliedner, Theodor (1800-64), 297 + + Floyer, Sir J. (1649-1734), 159 + + Foxglove, _see_ Digitalis + + Fracastoro, Girolamo (1483-1553), 96, 98 + + Fractures, 246-8 + + Frankfurt, 330 + + Franklin, Benjamin (1706-90), 171 + + Freud, S. (1856-), 293 + + Fry, Elizabeth (1780-1845), 171, 297 + + + Galbanum, 322 + + Galen of Pergamum (130-200), 1, 39, 50-3, 320; + his Medical System, 53-60; + in the Renaissance, 82-90 + + Galilei, Galileo (1564-1642), 103, 104-8, 108-9, 115, 135-6, 138, + 159, 356 + + Galls, 323 + + Galvani, Luigi (1737-98), 149-51 + + Galvanism, 149-51 + + Gastric Juice, 148, 303 + + Gay-Lussac, Joseph (1778-1850), 326 + + Gegenbaur, Karl (1826-1903), 204 + + Geneva, 300 + + Gengou, O. (1875-), 269 + + Gentian, 323 + + Gerhard, William (1809-72), 258 + + Germ Origin of Disease, 224-37 + + Giessen, 205 + + Gilbert, W. (1544-1603), 103 + + Ginger, 323 + + Glands, Ductless, 302-8 + + Glasgow, 249 + + Glucosides, 327-8 + + Glycogen, 214 + + Godlee, Rickman (1849-1925), 248 + + Goitre, 303-4 + + _Golden Bough, The_, 12-13 + + Gorgas, William C. (1854-1920), 279 + + Gout, 99 + + Graefe, Albrecht von (1828-70), 320-1 + + Gravity, 136 + + Greek Medical Lore, 322 + + Greek Medicine, 1-13 + + Guayaquil, 273 + + + Haffkine, Waldemar (1860-), 266 + + Hales, Stephen (1677-1761), 145-6, 147, 171, 180 + + Hall, Marshall (1790-1857), 207, 208 + + Haller, Albrecht von (1708-77), 139, 142-5, 151 + + Halley, Edmund (1656-1742), 167 + + Halsted, W. S. (1852-), 236, 248 + + Hartford, Conn., 237 + + Harvey, W. (1578-1657), 32, 103, 111-15, 135 + + Hashish, 322 + + Health of Towns Association (1840), 194 + + Heart, Aristotle on, 29, 31 + + Heberden, W., the elder (1710-1801), his _Commentaries_, 22 + + Helmholtz, Hermann von (1821-94), 213, 319-20 + + Herbs, 322-3 + + Hering, E. (1834-1918), 212 + + Herophilus of Chalcedon (_c._ 300 B.C.), 36-7 + + Hippocrates, 1, 8, 14-18, 102, 267, 342, 358-9 + + Hippocratic Collection, 9-10, 13-18, 22-3, 26, 95, 256, 342 + + _Hippocratic facies_, 26 + + Hippocratic Oath, 17-18 + + Hippocratic Practice, 18-26 + + Hippolytus, 11 + + Histology, 219, 222 + + Holmes, Oliver Wendell (1809-94), 237, 243 + + Hong Kong, 253 + + Hopkins, Sir Frederick Gowland, 311 + + Hormones, 307-8 + + Horsley, V. (1857-1916), 248 + + Hospital Gangrene, 239 + + Hospitals, 48-50, 77-81, 178-80, 198, 200 + + Howard, John (1726-90), 171, 180, 182 + + Humors, the Four, 34 + + Hunter, John (1728-93), 162, 165-6 + + Hunter, William (1718-83), 158, 165 + + Hunterian Museum, 166 + + Hygiene, 40, 169-72; + Roman, 45; + Medieval, 77-81; + 18th cent., 174 sqq.; + 19th cent., 192-203; + Tropical, 270 sqq. + + Hyoscyamus, 323 + + Hypodermic Syringe, 329 + + + Iatrochemistry, 127, 131-2 + + Iatrophysics, 127-31 + + Imhotep, 7, 8 + + Immunity, 184, 234, 252, 259-70, 276 + + Indian Hemp, 322 + + Indian Medicine, Early, 322 + + Industrial Revolution, 172-81 + + Infantile Paralysis, 270, 274 + + Infectious Diseases, 96, 98, 102, 201, 234-5, 358 + + Infirmaries, Roman, 49 + + Inflammation, 238-9 + + Influenza, 270, 280, 349, 359 + + Inoculation, 183-4, 261 + + Insanity, 286-93 + + Insulin, 306 + + Internal Medicine, 77, 95-102 + + Internal Secretions, 302-8 + + International Health Legislation, 193 + + International Red Cross Committee, 300 + + Invisible College, the, 124 + + Ionians, the, 4 + + Ipecacuanha, 95, 323, 330 + + ‘Irregular Sight’, _see_ Astigmatism + + Isaac of Kairouan (852-952), 67, 70 + + + Jackson, Hughlings (1834-1911), 211 + + Jamaica, 278 + + Jena, 220 + + Jenner, E. (1749-1823), 183 + + Johnson, Dr. (1709-84), 158 + + Jung, C. G. (1875-), 293-4 + + Juniper, 322 + + Justinian, Emperor, 46 + + + Kaiserswerth, 297-8 + + Kalar-azar, 272 + + Kepler, Johannes (1571-1630), 103, 104, 136, 319 + + Kitasato, Shibasaburo (_c._ 1860-), 253, 257, 264, 266 + + Klebs, E. (1834-1913), 253 + + Klebs-Loeffler Bacillus, 253 + + Koch, Robert (1843-1910), 184, 202, 229-30, 232, 234, 249-51, 253, + 321, 330 + + Kocher, T. (1841-1917), 303 + + Kölliker, Albrecht von (1817-1905), 222 + + Koronis, 11 + + Kymograph, the, 216-17 + + + Laënnec, René Théophile Hyacinthe (1781-1826), 160-1, 219 + + Laughing Gas, 237 + + Lavender, 323 + + Laveran, A. (1845-), 283 + + Lavoisier, Antoine Laurent (1743-94), 155-6, 205 + + Law, Reign of, 135-8 + + Lazarettos, 182 + + Lazear, 279 + + Leeuwenhoek, A. von (1632-1723), 39, 118, 120-1 + + Leipzig, 215 + + Leonardo da Vinci (1452-1518), 83-5 + + Leprosy, 78-80, 98, 162, 271 + + Lesions, 157, 160 + + Licorice, 322 + + Liebig, Justus von (1803-73), 205-7, 225, 235, 326 + + Lind, James (1716-94), 170-1, 180-1 + + Linseed, 323 + + Leyden, 131, 139-42 + + Lister, Lord (1827-1912), 184, 229, 237-43, 248, 321, 336 + + Liverpool, 196 + + Lockjaw, _see_ Tetanus, 256-8 + + Loeffler, Friedrich (1852-1915), 253 + + London Hospital, 178 + + Louisiana, 202 + + Louvain, 85 + + Ludwig, Karl (1816-95), 215-19 + + Lyons, 42 + + + Macewen, William (1848-1926), 248-9 + + Magendie, François (1783-1855), 238, 326 + + Magic, 3, 16 + + Malaria, 174, 251, 271, 330; + history, 280-6 + + Male Fern, 323 + + Mallow, 323 + + Malpighi, Marcello (1628-94), 114, 116-20, 302 + + Malta Fever, 254-6, 268 + + Manson, Patrick (1844-1922), 283 + + Marburg, 215 + + Marine Hospital Service, 200, 201 + + Marjoram, 323 + + Marseilles, 42, 182 + + Massachusetts, 202, 235 + + Massage, 247, 248 + + Mather, Cotton (1663-1728); + Increase (1639-1723), 183 + + Mayo, Charles & William, 248 + + Mayow John (1645-79), 126, 151-2, 189 + + Mead, Dr. Richard (1673-1754), 183 + + Measles, 67, 252, 349, 359 + + Mechanics, 106, 122, 138 + + Medical Theorists in the Renaissance, 126-34 + + Medical Research Council, 197, 348 + + Medieval Medical Revival, 68-72 + + -- Anatomy, &c., 72-7 + + -- Hospitals and Hygiene, 77-81 + + Mendel, 222 + + Mercury, 162, 322, 325, 330 + + Mesopotamian peoples, 7 + + Metabolism, 107, 108, 220 + + Metschnikoff, Élie (1845-1916), 223 + + Mezger, Johann (1839-19-), 247 + + Michael Scot (d. 1235), 68 + + Michelangelo, 83 + + Microscope, 105, 115-22, 159 + + Microscopic Analysis, 115-22, 138 + + Midwives, 295 + + Milan, 81 + + Military Medicine, 169-70 + + Mill, J. S. (1806-73), 191 + + Ministry of Health, 197, 291 + + Minoans, the, 3-5 + + Mint, 322 + + Mitchell, S. Weir (1830-1914), 318 + + Mohl, Hugo von (1805-72), 220-1 + + Moivre, Abraham de (1667-1754), 167 + + Mondino di Luzzi (c. 1270-1326), 74, 76 + + Montagu, Lady Mary Wortley (1689-1762), 183 + + Montpellier, 74, 76 + + Morgagni, Giovanni Battista (1682-1771), 157-8 + + Morphine, 326 + + Morton, William Thomas Green (1819-68), 235 + + Mosquito Net, 45 + + Mosquitoes, 273-80 + + Müller, Johannes (1807-58), 28, 211-13, 356 + + Murphy, J. B. (1857-1916), 248 + + Mustard, 323 + + _Mustelus laevis_, 28-9 + + Myrrh, 322 + + Myxoedema, 304-5 + + + Nägeli, Karl v. (1817-91), 221-2 + + Nature-Worship (Animism), 3, 12, 16 + + Natural Spirit, 56 + + Naval Medicine, 170-1 + + Near Sight, 317, 318 + + Nervous Integration, 308-11 + + Nestorians, the, 66 + + New York, 202, 248 + + Newton, Sir Isaac (1642-1727), 104, 136-8, 186 + + Nightingale, Florence (1820-1910), 291, 298-301 + + Nîmes, 42 + + Noguchi, 273-5 + + Norfolk, Va., 198 + + Nursing, 180, 295-301 + + Nutrition, 311-13 + + Nux vomica, 322, 326 + + + Obstetrics, 161-6, 236, 243 + + Oil of Wintergreen, 327 + + ‘Old Sight’, 316, 319 + + Ophthalmic Surgery, 320-2 + + Ophthalmoscope, 213, 319, 321 + + Opium, 326 + + Owen, R. (1804-92), 204 + + Oxygen, 126, 154, 156, 189 + + + Padua, 75, 86, 108, 110, 139, 157 + + Panama, 286 + + Pancreas, the, 215, 306, 325 + + Paré, Ambroise (1517-90), 92-4, 162, 247 + + Paris, 76, 85, 160, 288 + + Park, W. H. (1863), 266 + + Pasteur, Louis (1822-95), 148, 184, 202, 225-35, 239, 249, 253, 261, + 321 + + Pathology, Medieval, 77; + Modern, 301-13; + Cellular, 219-24; + Comparative, 251-2 + + Pavia, 149 + + Peel, Sir Robert (1750-1830), 191 + + Pelletier, Pierre Joseph (1788-1842), 326 + + Percival, Thomas (1740-1804), 170-1, 180 + + Percussion, 160 + + Pergamum, 52 + + Pest Houses, 180, 181 + + Petty, Sir William (1623-87), 166-7, 169 + + Pflüger, E. F. W. (1829-1910), 205 + + Pharmacology, 323, 328-9 + + Philadelphia, 171-2, 258 + + Philip of Macedon, 27 + + Philosopher’s Stone, the, 124 + + Phlogiston, 132, 151-4 + + Phthisis, 341-3 + + Physical Synthesis, 102-8 + + Physiological Synthesis, 203-11 + + Physiology: of Galen, 56-60; + Medieval, 77, 129; + Renaissance, 95, 99, 100, 108-15; + Earlier 19th cent., &c., 207-19; + Modern, 122, 127, 138, 142-51, 301-13 + + Pinel, Philippe (1745-1826), 288 + + Pisa, 104, 105 + + Plague, 80-1, 182, 185, 200-1; + Bacilli of, 253-5; + Immunization, 266 + + Plaster of Paris, 246 + + Plato, 14, 27, 29 + + Plethora, 39 + + Pneumatism, 38, 56, 58 + + Political Economy, 166-7 + + Polypharmacy, 324 + + Poppy, 323 + + Population, 176 + + Post-mortems, 156-9 + + Pravaz, C. (1791-1853), 329 + + Preventive Medicine, 192-203 + + Priestley, Joseph (1733-1804), 154-5, 189-90 + + Pringle, Sir John (1707-82), 169-70, 171, 180 + + Prison Medicine, 171-2 + + Prophylaxis, 265 + + Proteids, 215 + + Proteins, 206, 311 + + Protoplasm, 221-2 + + Prout, W. (1785-1850), 148 + + Psyche, the, 31-3, 133 + + Psycho-analysis, 293-5 + + Psychology, 293-5 + + Ptomaine, 259 + + Ptolemy, 36, 40 + + Public Health, 192-203 + + Puerperal Fever, 243 + + Pulmonary Tuberculosis, 341-3 + + Pulse Watch, 159 + + Pulsimeter, 109 + + Putrefaction, 225-8, 231-2, 239 + + Pyaemia, 239 + + + Qualities, the Four Primary, 33-4 + + Quarantine, 173, 182, 194, 197 + + Quetelet, Lambert (1796-1874), 168 + + Quinine, 281-2, 326, 330, 332 + + + Radcliffe Infirmary, 296 + + Radiography, 245 + + Ragusa, 81 + + Raphael, 83 + + Réaumur, René Antoine de (1683-1757), 146-7, 148 + + Reed, W. (1851-1902), 279 + + Registration Act (1838), 195 + + Research, Method and Meaning of, 135 + + Respiration, 151-6, 205 + + Reymond, E. Du Bois-, (1818-96), 151 + + Rhazes of Basra (860-932), 67, 70 + + Rheumatism, 98, 358-9 + + Rhubarb, 323 + + Rickets, 181, 312, 313 + + Rochester, Minn., 248 + + Röntgen, Wilhelm Conrad (1845-1923), 244-5 + + Röntgen Rays, 244-5 + + Rokitansky, Karl (1804-78), 158-9 + + Roman Empire: Medical Teaching, 41-4; + Medical Services, 45-8; + Hospitals, 48-50 + + Ross, Ronald (1857-), 283 + + Roux, Pierre (1853-), 263 + + Royal Society, 104, 118, 124, 167 + + Rush, Benjamin (1745-1813), 171-2 + + + St. Luke, 63 + + St. Bartholomew I., 49, 51 + + St. Bartholomew’s Hospital, 178-9 + + St. Gall, 50 + + St. Thomas’s Hospital, 298 + + Salerno, 64-5 + + Salicin, 327 + + Salts of Copper, 322 + + Salts of Lead, 322 + + San Francisco, 201 + + Sanctorius (1561-1636), 107-9, 159 + + Sanitary Commission, 195 + + Sanitation, 45, 194 + + Saragossa, 42 + + Scarlet Fever, 185, 201, 270, 349 + + Schaudinn, Fritz (1871-1906), 331-2 + + Schick, B., 264 + + Schiff, Moritz (1823-90), 304 + + Schleiden, Matthias Jakob (1804-81), 219-20 + + Schmiedeberg, Oswald (1834-1921), 328 + + Schultze, M. (1825-74), 222 + + Schwann, T. (1810-82), 220-1 + + Scurvy, 170, 181, 313 + + Seamen’s Hospital Society, 198 + + Secretions, Internal, 302-8 + + Semmelweis, Ignaz (1818-65), 243 + + Septicaemia, 239 + + Serpent, Cult, 4-5, 8, 11 + + Sertürner, Adolf (1783-1841), 326 + + Sesame, 323 + + Sex organs, 306 + + Shaftesbury, 7th Earl (1801-85), 290 + + Shakespeare, William, 26 + + Shattuck, Lemuel (1793-1859), 202 + + Sherrington, Sir Charles, 309 + + ‘Shock’, Nervous, 310-11 + + Sierra Leone, 276, 278 + + Sight, Deficient, 316-20 + + Simon, Sir John (1816-1904), 196-7 + + Simpson, Sir James Young (1811-70), 235 + + =606=, 332 + + Sleeping Sickness, 234, 272, 332 + + Sleepy Sickness, 272 + + Small-pox, 182-5, 198, 200, 261, 265, 343 + + Smith, Thomas S. (1788-1861), 171, 178, 193-6 + + Smyrna, 52 + + Spallanzani, Lazaro (1729-99), 147-8 + + Specialization, Scientific, 186-92, 359 + + Specific Energies, Law of, 212-13 + + _Speculum matricis_, 164 + + Spencer Wells, _see_ Wells + + Spencer Wells Forceps, 244 + + Spinal anaesthesia, 236-7 + + _Spirochaeta pallida_, 331-2 + + Spotted Fever, 269-70 + + Sprue, 272 + + Stahl, George Ernest (1660-1734), 132-3, 151, 288 + + Starling, E. H. (1866-1927), 308 + + Statistics, Medical, 334-50; + Vital, 166-8 + + Stavesacre, 323 + + Stethoscope, the, 160-1 + + Stoic Philosophy, 54 + + Stomach, Ruminant, 28 + + Storax, 323 + + Strychnine, 326 + + Sublimation, 294-5 + + Superstition, 3, 6 + + Suprarenal bodies, 306-7 + + Surgery: Greek, 49; + Medieval, 76-7; + Renaissance, 92-4; + 18th cent., 161-6; + Modern, 243-9 + + Süssmilch, J. P. (1707-82), 167-8 + + Swammerdam, J. J. (1637-80), 39, 121-3, 140, 143 + + Switzerland, 303 + + Sydenham, Thomas (1624-89), 96, 100-2, 282, 342 + + Sylvius, Franciscus (1614-72), 131-2, 139, 148 + + Syphilis, 98-9, 162, 251, 269, 291, 330-2, 337 + + + Telescope, the, 105 + + Temperaments, Four, 97 + + Terebinth, 323 + + Tetanus (Lockjaw), 23, 256-8, 260, 264, 265; + immunization, 266-7 + + Thaddeus of Florence (1223-1303), 72 + + Theophrastus (372-287 B.C.), 35 + + Thermometer, the, 108-9; + clinical, 159 + + Theseus, 12 + + Thessaly, 14 + + Thyroid Gland, 303-6, 325 + + Thyroxin, 305 + + Tiberius, Emperor (1st c.), 42 + + Tobacco, 95, 99, 323 + + Toulon, 182 + + Tours, 185, 253 + + Toxins, 259-60, 262-7, 330-3 + + Trachoma, 321-2 + + Tragacanth, 323 + + Trephining, 18-19, 20, 63, 64, 72 + + Tropical Diseases, 198 + + Tropical Hygiene and Medicine, 170, 270-86 + + Tuberculosis, 234, 250, 330, 359 + + Tübingen, 220 + + Tuke, W. (1732-1822), 288 + + Turpentine, 322 + + =205=, 332 + + Typhoid Fever, 185, 201, 258-61, 265; + immunization, 267-70; + death-rate, 271; + state, the, 25 + + Typhus, 98, 258-9, 271 + + + United States, 171, 290; + Preventive Medicine in, 197-203; + Public Health Service (1912), 201; + Sanitary Commission, 300 + + Universities, Medieval, 70-2 + + Urea, 205, 214 + + Uterus, Aristotle’s nomenclature of, 28, 29 + + Utilitarian Philosophy, 190 + + + Vaccination, 184 + + Vaccines, 261-2, 265, 266, 268, 325 + + Vaso-Motor Mechanism, 215 + + Venereal Disease, _see_ Syphilis + + Venice, 81 + + Ventilation, 146, 147 + + Vesalius, Andreas (1514-64), 85-92, 108, 135, 140 + + Vespasian, Emperor (1st cent.), 42 + + Victoria, Queen, 195 + + Vienna, 158, 160, 215, 236, 243 + + Virchow, R. (1821-1902), 222, 238, 253, 258, 264 + + Vital Spirit, 58 + + Vital Statistics, 166-8 + + Vitalism, 127, 132-3 + + Vitamins, 311-13 + + Volta, Alessandro (1745-1827), 149-50 + + Voltaic pile, 149 + + + Waller, A. V. (1816-70), 238 + + Wassermann, August von (1866-), 269 + + Water, 156 + + Water Supply, 178 + + Wells, Horace (1815-45), 237 + + Wells, Thomas Spencer (1818-97), 243-5 + + Whooping Cough, 98 + + Widal, F. (1862-), 268 + + William of Saliceto (1215?-1280?), 72 + + Withering, W. (1741-99), 328 + + Wöhler, Friedrich (1800-82), 206, 214, 327 + + Wormwood, 323 + + Wright, A. (1861-), 223 + + Würzburg, 222 + + + X-rays, 244-5, 247 + + Xavier, Marie François (1771-1802), 219 + + + Yellow Fever, 172, 194, 198, 200, 201, 272; + history of, 273-80 + + Yersin, Alexandre (1863-), 253, 263 + + York, 288-9 + + Young, Thomas (1773-1829), 217, 319-20 + + + Zürich, 215, 253, 294 + + +Transcriber’s Notes. + +Italic text is indicated with _underscores_, bold text with =equals=. +Small/mixed capitals have been replaced with ALL CAPITALS. + +Evident typographical and punctuation errors have been corrected +silently. Inconsistent spelling/hyphenation has been normalised. + +The usage of "cholestrol" is the author’s. + +A half-title and chapter title reiteration have been discarded. + +To improve text flow, illustrations have been relocated between +paragraphs. + +Cover art created for this eBook is granted to the public domain. + + +*** END OF THE PROJECT GUTENBERG EBOOK 78966 *** |