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diff --git a/34603.txt b/34603.txt new file mode 100644 index 0000000..7d0b91e --- /dev/null +++ b/34603.txt @@ -0,0 +1,5147 @@ +The Project Gutenberg EBook of Epidemics Examined and Explained: or, +Living Germs Proved by Analogy to be a Source of Disease, by John Grove + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Epidemics Examined and Explained: or, Living Germs Proved by Analogy to be a Source of Disease + +Author: John Grove + +Release Date: December 9, 2010 [EBook #34603] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK EPIDEMICS EXAMINED *** + + + + +Produced by Bryan Ness, Keith Edkins and the Online +Distributed Proofreading Team at http://www.pgdp.net (This +file was produced from images generously made available +by The Internet Archive/American Libraries.) + + + + + +Transcriber's note: A few typographical errors have been corrected: they +are listed at the end of the text. + + * * * * * + + +Page numbers enclosed by curly braces (example: {25}) have been +incorporated to facilitate the use of the Table of Contents. + + * * * * * + + +EPIDEMICS + +EXAMINED AND EXPLAINED: + +OR, + +LIVING GERMS + +PROVED BY ANALOGY TO BE + +A SOURCE OF DISEASE. + +BY + +JOHN GROVE, M.R.C.S.L. + +AUTHOR OF "SULPHUR AS A REMEDY IN EPIDEMIC CHOLERA." + +LONDON: + +JAMES RIDGWAY, PICCADILLY. + +MDCCCL. + + * * * * * + + + "The tendencies of the mind, the turn of thought of whole ages, have + frequently depended on prevailing diseases; for nothing exercises a + more potent influence over man, either in disposing him to calmness and + submission, or in kindling in him the wildest passions, than the + proximity of inevitable and universal danger."--_Hecker's Epidemics of + the Middle Ages._ + + "The grand field of investigation lies immediately before us; we are + trampling every hour upon things which to the ignorant seem nothing but + dirt, but to the curious are precious as gold."--_Sewell on the + Cultivation of the Intellect._ + + * * * * * + + +TO + +BENJAMIN GUY BABINGTON, F.R.S., M.D., + +PHYSICIAN TO GUY'S HOSPITAL, + +AND + +PRESIDENT OF THE EPIDEMIOLOGICAL SOCIETY, + +ETC. ETC. + +THESE PAGES ARE, BY HIS KIND PERMISSION, + +Respectfully Dedicated, + +BY HIS OBLIGED AND FAITHFUL SERVANT, + +THE AUTHOR. + + * * * * * + + +{v} + +PREFACE. + +The following pages have been written with a view to render some aid in +establishing a sound and firm basis for future research, on that absorbing +topic, the Causes and Nature of Epidemic Diseases. + +The amount of information already published on Fevers, on the Exanthemata, +and on the Plague, is truly astonishing, and the more so when it is +considered, that at present no rational account or explanation is given of +the causes of these affections. + +It appears to me but reasonable to suppose that as every thing on this +earth has been created on a wise and unerring principle, Epidemic and +Infectious Diseases are only indicative of some serious errors in our +social arrangements and habits. The dangers and misery brought upon us by +disease, may, as shewn by Dr. Spurzheim and Mr. Combe, be warnings against +the infringement of the natural laws. + +Indeed, what is more rational than to suppose that the Seeds of Disease are +coeval with the fall of man. His first disobedience {vi} brought +death:--that his subsequent errors should hasten its approaches is not to +be marvelled at. The undetected murderer, though he may escape the +punishment human justice would inflict upon him for his delinquency, +suffers a penalty in the tortures of conscience, infinitely more horrifying +than the most ignominious death. The law of nature is triumphant. + +No less certain, though after a different manner, are the consequences of +minor forms of disobedience. It is so ordained, that certain diseases shall +arise, under peculiar conditions, which may have been brought about by a +train of causes, easily imagined, and difficult to be explained, but all +having their origin in the vices and errors of man in his moral and social +relations. + +If man neglects the cultivation of the ground; with rank vegetation, the +germs of fever will invisibly grow and multiply; if he harbours that which +is rotten and corrupt, he is himself consumed by those agents destined to +remove the rottenness and corruption; it is a part of the law of nature +that there should be active and energetic agents for this purpose. The +seeds of disease, like the seeds of plants, may be shewn to have {vii} +their indigenous localities; like them they may be spread and multiplied; +like them they may lie dormant, and after awhile spring as it were into +active existence; like them, when the soil and other conditions favour, +they are ever ready to make their appearance. And this is the law, the +germs of all disease exist, and have existed. Despise the dictates of +nature, be careless of yourself and those around you, neglect to use the +means which a noble intelligence has placed at your command, and above all, +transgress the laws of God, then will disease pursue and attend you, as the +conscience of the murderer pursues and attends him until he is finally cut +off. + +His wants and necessities, his sufferings and privations, are the basis of +the intellectual progress of man. The wonders of Omnipotence are revealed +through the whirlwind, the storm, the pestilence, and the famine. + +The constructive and perceptive faculties of man have been developed by the +necessity of protecting himself from injury by winds and rains; his +intellectual faculties have been cultivated, by the sufferings of disease +having led him to the study of {viii} organization and life, to discover +the cause,--and to chemistry, and other sciences for the cure of his +ailments. + +Famine and distress have aroused his emotions, and softened down his +asperities, so that what appears at first to be the infliction of a Curse +without Pity, is in reality a Judgment with Mercy. + +It occurred to me, that on the formation of the Epidemiological Society, +the first question for consideration should be, What is the nature of those +agents, which induce Epidemic Diseases? are they composed of animate or +inanimate matter? In other words, do the manifestations of these diseases +exhibit the operations of living or of chemical forces. + +Having, in my study, dwelt on the subject with an earnest desire to find +the truth, I put the suggestion, with my ideas, before the public to reject +or receive them. If they be rejected, I can but think a full discussion of +the enquiry will lead to the most important results. If they be received +with favour, I doubt not others, with more ability, will take up the strain +and resolve the discords into harmony. + + J. G. + + _Wandsworth, September, 1850._ + +{ix} + +CONTENTS. + + PAGE + INTRODUCTION 1 + + CHAPTER I. + + IS IT PROBABLE THAT EPIDEMIC, ENDEMIC, AND INFECTIOUS + DISEASES, DEPEND UPON VITAL GERMS + FOR THEIR MANIFESTATIONS? 11 + + CHAPTER II. + + THE NUMBER AND VALUE OF FACTS TO SUPPORT + THE PROPOSITION. + + SECTION I.--On Reproduction 22 + + SECTION II.--Historical Notice of Epidemic Diseases 34 + + SECTION III.--The Dispersion of Plants and Diseases 64 + + SECTION IV.--The Relation between Epidemic and Endemic + Diseases 96 + + CHAPTER III. + + THE REASONABLENESS OF THE APPLICATION OF + THE FACTS TO THE INFERENCE. + + SECTION I.--The Chemical Theory of Epidemics untenable 108 + + SECTION II.--The Animalcular Theory of Epidemics untenable 128 + + SECTION III.--Sketch of the Physiology and Pathology of + Plants and Animals 138 + + CHAPTER IV. + + RESULTS IN PROOF OF THE TENABLENESS OF THE + PROPOSITION. + + SECTION I.--Observations on some of the Laws of Epidemic + Diseases 155 + + SECTION II.--What is the nature of those Poisons which most + resemble the Morbid Poisons in their effects on the body? 166 + + SECTION III.--What results do we obtain from the effects of + remedial agents, in proof of the hypothesis? 176 + + CONCLUSION 189 + + * * * * * + + +{1} + +INTRODUCTION. + +It is one thing for a man to convince himself, but a very different thing +to be able to convince others. + +I am not now speaking of a conviction arising from the impression made by a +few startling facts, nor of one forced on the mind by early prejudices, or +by the dogmas of the schools, but of a conviction arising from careful +enquiry. + +In the course of that enquiry, the collector of facts, sees their relations +to the idea in his mind, in a multiplicity of ways, from their remaining, +each, as one succeeds the other, an appreciable time on the sensorium, and +undergoing a certain process of comparison and relation, with all other +facts and ideas which have been previously stored up. As the materials for +an edifice which have been shaped and prepared in accordance with the +completion of the design, so do the facts and ideas which are accumulated +{2} in the mind, become shaped and prepared for the elimination of a truth. +The ultimate design of the architect can no more be conceived by the +examination of the framework of a window, or the capital of a column, than +the whole truth of a proposition by the examination of separate facts; the +whole must be conceived and all the relations of all the parts thoroughly +understood, before the architect can be comprehended or the harmony of his +design appreciated. + +The process of thought in the minds of the architect, and in the framer of +a proposition, is never exactly the same as in those who contemplate and +examine their completed works. Much may be done, however, by both to aid +others in comprehending them. The more accurately they keep in view the +course their minds have taken, the more readily will their descriptions be +understood. + +To simplify the elements of our knowledge is to give others a ready access +to our thoughts. + +To arrange the course of our ideas in harmony with the elements of our +knowledge should be the end of all writing, as it is the only means of +multiplying knowledge. {3} + +It is not the mere accumulation of facts which constitutes science, any +more than a collection of building materials constitutes a house, it is the +arrangement and adaptation of the means to the end by which the house +becomes built and science cultivated. + +These reflections have been suggested by the circumstance that for the last +3000 years and upwards, Pestilences have at certain intervals done their +work of destruction, and opened the springs of misery to untold millions, +and yet I see not that we are much further advanced as to the knowledge of +the cause of these inflictions than the Jews in the time of Moses. In the +Levitical law, as I shall have occasion more particularly to shew +hereafter, were directions specially given in reference to the plague of +leprosy; what means should be adopted for the cure of the disease, and for +preventing its extension, and moreover pointing very significantly to +certain facts having connexion with the cause of the affection. Since that +time historians generally, and medical writers in particular, have +diligently recorded their observations and accumulated facts, on the +various desolating plagues which {4} have afflicted mankind. Some of these +men have grappled with the whole subject, and endeavoured to shew the +presumed relation of the supposed causes in all their intricacies, but it +is hardly necessary to say that all have signally failed in their attempts +to furnish us with any practical information. + +Satisfied in my own mind that the whole subject is beyond the labour of one +man, and impressed with the belief that the basis of the enquiry is in +anything but a satisfactory state, I have applied myself entirely to the +study of the groundwork only, as the primary proceeding for a solid +superstructure. + +The days are past, when imaginary spirits, ethers, and astronomical +phenomena, were believed to have any essential influence over our destinies +in a physical point of view; we have therefore to deal with _matter_ in +some form or other. + +The question, therefore, which I have proposed for enquiry, is, whether the +matter which causes epidemic and endemic diseases, exhibits the properties +of inorganic or organized matter. + +The properties and qualities of organized {5} bodies, as well as those of +inorganic matter, need but be stated, and in some instances we may picture +to ourselves the object, without having seen it, and not be very far from a +true conception. But for this purpose a clear and definite idea must be +previously formed, and have taken possession of the mind, of the great +general divisions of objects in the material world. + +Having made these preliminary remarks, I have suggested a certain mode of +procedure in making enquiries of this kind, not perhaps in strict +accordance with logical systems, but on the principle of nature's +operations in our own minds, which appears to me, when reduced to a +systematic and simple form, to be sufficiently clear and strict for +synthetical application, and so concise as to be usefully and practicably +applied. + +In endeavouring to establish a theory for the explanation of extraordinary +phenomena, there are certain rules which should guide us in the thorny and +treacherous path of speculation. But these rules readily flow from the +train of thought, and if we examine our own minds during their operations, +we {6} shall find that the following is the course of our instinctive +reflections. It is a course we adopt as the test of theories when formed, +and is a guide in all cases for their construction. + +We first commence with an idea, which exists in our minds in the form of a +proposition: then the following rules naturally suggest themselves:-- + +1. The probability of the value of our proposition from inference. + +2. The number and value of facts to support the proposition. + +3. The reasonableness of the application of the facts to the inference. + +4. What amount of information in the form of results can be produced in +proof of the tenableness of the proposition.[1] + +In illustration of the value of these rules the history of Dr. Jenner's +discovery affords an appropriate example. To use the words of Dr. Gregory, +"he appears very early in {7} life to have had his attention fixed by a +popular notion among the peasantry of Gloucestershire, of the existence of +an affection in the cow, supposed to afford security against the Small Pox; +but he was not successful in convincing his professional brethren of the +importance of the _idea_." + +The popular notion of the peasantry originated the idea in Jenner's mind, +and it became fixed there as a proposition. + +1. He commenced his enquiry by observing that the hands of milkers on the +dairy farms were subject to an eruption, and he _inferred_ that the notion +of the peasantry bore the stamp of probability, which strengthened the idea +in his mind and gave force to the proposition. + +2. His next step was to accumulate facts; he found on enquiry that the +persons engaged on these farms in milking, possessed an immunity from Small +Pox to an extent sufficient to strengthen the value of his proposition. + +3. The reasonableness of the application of the facts to the inference is +clear from the coincidence that the eruption on the hands of the dairy +people bore a striking {8} resemblance to the Small Pox, and as this +disease does not usually occur twice in the same individual, the inference +was most reasonable that this eruption protected the people from Small Pox. + +4. We have but to take the almost universal adoption of vaccination, and +its acknowledged prophylactic powers against the propagation of Small Pox +to shew the application of our fourth rule.[2] + +Between the conception of the idea and the accomplishment of Jenner's +designs, vaccination seems to have undergone an incubation of nearly twenty +years. During that period, with an energy and perseverance only to be +obtained by confidence, did this great man brood over and elaborate his +idea; and well might the 14th day of May, {9} 1796, be styled the birth day +of vaccination, for on that day was a child first inoculated from the hands +of a milker. + +In adopting the above method I have endeavoured to bear in mind M. +Quetelet's observations on the requirements necessary for medical +authorship; he says, "All reasonable men will, I think, agree on this +point, that we must inform ourselves by observation, collect well-recorded +facts, render them rigorously comparable, before seeking to discuss them +with a view of declaring their relations, and methodically proceeding to +the appreciation of causes." + + * * * * * + + +{10} + +{11} + +CHAPTER I. + +IS IT PROBABLE THAT EPIDEMIC, ENDEMIC, AND INFECTIOUS DISEASES, DEPEND UPON +VITAL GERMS FOR THEIR MANIFESTATIONS? + +It is, I believe, almost universally considered that Epidemic, Endemic, and +Infectious diseases, originate from some imaginary poisons of a specific +nature, each disease having its own peculiar poison. That this conception +should have taken possession of the minds of men, is most natural from the +symptoms which characterize these diseases, but when we come to enquire +into the nature of these agents, or supposed poisons, we are at once struck +with the idea that they exhibit one peculiarity which separates them in a +marked manner, from those poisons with which we are familiar; for the +poisons of Small Pox, Measles, Scarlet Fever, Hooping Cough, Fever, &c. +possess the power of multiplication, or spontaneous increase, a property +which attaches only to the organic kingdom, and is never known in the +inorganic kingdom. The source of most of the poisons is to be found among +mineral or vegetable products. A mineral in combination with an acid or +oxygen may become a poison, and {12} nitrogen in various combinations with +oxygen, hydrogen, and carbon, or with carbon alone, may become a poison; +these combinations are, however, in most instances the products of +vegetable life, others again are obtained from the animal kingdom, such as +the poison of the serpent, &c. but in all of these instances, there is not +one in which the power of self-multiplication is to be found. + +We are, therefore, constrained to admit that this feature, which +distinguishes poisons, is one well worthy attentive consideration. The +varieties of poisons may be classified into those which act topically as +escharotic poisons, those which act chemically on the blood, and those +whose effects are manifested in inducing a speedy annihilation of organic +or vital action, as in the case of hydrocyanic acid, which is supposed +specifically to affect the nervous centres from which originate the vital +manifestations. It is rather remarkable that the vital poisons (as I will +call them for distinction), seem to have their appropriate locality in the +blood, they do not primarily affect one organ more than another, all the +effects we witness resulting from them are to be traced progressively from +the blood to other parts of the body. When a person is inoculated with +small pox, a very minute portion (indeed it is impossible to say how minute +it may be) is sufficient, when absorbed, to excite a certain train of +symptoms, all due to absorption of the materies of the disease, and the +process by which {13} that materies arrives at maturity, is that known in +the vegetable world as the fructification; this process of fructification +is a process of development and increase. + +I here may repeat that among all the poisons known, constituted as they are +of various combinations of elementary matter, they are without exception +destitute of the power of development or increase. Now, it is pretty +accurately known what amount of these poisons is necessary to produce their +effects on the living body; we can say how many drops are sufficient of +hydrocyanic acid of Scheeles strength, to destroy a man instantaneously. +Again, how many grains of arsenious acid are sufficient to induce such an +inflammatory condition of the stomach and intestine as will end in death, +and how many grains of morphia, will bring about a fatal coma,--but who +shall say the amount of the vital poisons necessary to produce their +results? It far exceeds the limit of conjecture, to what extent the +dilution of miasmatic or contagious matter may be carried, and the poison +yet be capable of committing in a short time the most frightful ravages. + +We may fairly then infer, that if a quantity of matter inappreciable in +amount be sufficient to exhibit the characters of growth and increase, that +it is endowed with the properties of vitality. That the poisons of scarlet +fever, of measles, and of small-pox have this power of growth and increase, +is as much a matter of universal belief as that "the sun {14} will rise and +set to-morrow, and that all living beings will die." + +This power of individual increase, or reproduction, is the very summit of +vital manifestation; indeed Coleridge, in his Theory of Life, (in which he +says, "I define life as the _principle of individuation_, or the power +which unites a given _all_ into a whole that is presupposed by all its +parts,") places reproduction in the first rank, and expresses his +hypothesis thus: "the constituent forces of life in the human living body +are, first, the power of length or reproduction; 2nd, the power of surface, +or irritability; 3rd, the power of depth, or sensibility--life itself is +neither of these separately, but the copula of all three." + +Extensive research is not required to shew that many thinking men believe +in the existence of living organic beings, as the elements of contagious +and epidemic diseases; the idea indeed seems to flow spontaneously in that +direction. Whenever thought, and enduring contemplation, have been +concentrated on the subject, the result appears to have been the same, a +firm conviction in each individual mind that a vital force must be in +operation; or as Schlegel would define it, "a living reproductive power, +capable of and designed to develope and propagate itself."--"Its Maker +originally fixed and assigned to it the end towards which all its efforts +were ultimately to be directed." + +Referring further to beings having the property of reproduction and +propagation, he says, (using {15} the word nature here evidently as the +vital principle for want of a better term,) "Nature indeed is not free like +man, but still is not a piece of dead clockwork. _There is life in +it._"--"Thus we know that even plants sleep, and that they too as much as +animals, though after a different sort, have a true impregnation and +propagation." + +When Schlegel wrote this, how little could he have imagined the intricacy +of this proceeding among the lower forms of vegetation. It has been shewn +by Suminski, and verified by many others, that the mode of impregnation, +and the period at which it occurs in the ferns, do not at all correspond to +the general notion on this subject. He has discovered in the early +development of the frond of ferns certain cells, which he denominates +antheridia, or sperm cells; these contain in their cavity a number of +subordinate cells, each containing a spermatazoon. At a certain period of +the progress of the frond, the parent cells become ruptured and liberate +the spermatoza, these move about in a mucilaginous fluid, which bedews the +inferior surface of the frond, and become the means of impregnating the +germ cells, or pistillidia, with which they readily come in contact. Thus +the process of impregnation in these plants occurs during the germination, +or what corresponds to the period of germination in the seeds of exogenous +and endogenous plants. + +I have referred to the discovery of Suminski in {16} this place to recal to +the mind the great and incomprehensible wonders of creation, for who could +conceive it possible or feasible that even for the impregnation of an +inferior vegetable, animal life should form an indispensable and essential +appurtenant of the process. Truly may we say with Coleridge, of plants and +insects, "so reciprocally inter-dependent and necessary are they to each +other, that we can almost as little think of vegetation without insects, as +of insects without vegetation." + +I will make but two more quotations on the supposed vital character of the +germs of disease. "That the air and atmosphere of our globe is in the +highest degree full of life, I may, I think, take here for granted, and +generally admitted. It is, however, of a mixed kind and quality, combining +the refreshing breath of spring with the parching simooms of the desert, +and where the healthy odours fluctuate in chaotic struggle with the most +deadly vapours. What else in general _is the wide-spread and spreading +pestilence_, but a living propagation of foulness, corruption, and death? +Are not many poisons, _especially animal poisons, in a true sense, living +forces_?"--Schlegel.[3] + +It were useless to multiply quotations to shew {17} that the opinions here +entertained are matters of general belief among thinking men.[4] I will at +once then conclude with an observation of Dr. C. J. B. Williams: he puts +the question, "Does the matter of contagion consist of vegetable seeds? Are +infectious diseases the results of the operations and invasions of living +parasites, disturbing in sundry ways the structures and functions of the +body, each after its own kind, until the vital powers either fail or +succeed in expelling the invading tribes from the system?" + +And this expression, the seeds, is an universal expression, it is a +"Household Word" in connexion with disease. That it has obtained this +position in the popular vocabulary is alone a proof of the applicability of +the term to the thing intended to be {18} signified. Popular notions, as we +have seen in the case of Jenner's discovery, are not to be unheeded. An +instance occurs to me, it was a popular belief, that in acne punctata, the +matter of a sebaceous follicle, was itself, when pressed out, a worm, the +dark portion which results from the accumulation of dust upon the matter at +the mouth of the follicle was supposed to be the head of the maggot, as it +was called; subsequent observation, however, has proved that though this +matter is not a worm, it contains an animal within its substance, the +Acarus folliculorum. + +The popular notions found among savage tribes as to the efficacy of certain +remedies in the cure of disease have been the means of furnishing us with +some of our most valuable medicines, indeed it is almost impossible to say +whether originally man did not derive his remedies from the herbs and trees +by an instinctive faculty impelling him, as it does the animals when in a +state of liberty and with freedom of range, to seek certain plants as they +avoid others. + +It is well known that animals when indisposed will find out some spot as if +almost led to it by a visionary guide where the "healing plant" is to be +discovered. I am told that sheep have this faculty, and that they will, +when affected with the rot, feed upon some plant when they can discover it, +which eradicates the disease. + +Almost every one is familiar with the fact that cats and dogs will crop +herbage and eat it; I have {19} seen them frequently leave the house and +proceed to the grass in the most business-like manner, partake of some +quantity, and quietly return. + +A close observer of diseased animals might obtain some useful information +by noticing the plants cropped by them while in that condition. The +observations should be made in a variety of districts in consequence of the +uncertain distribution of some even of the most commonly scattered plants; +in one year they may be abundant, but in another they may be almost +entirely absent from the same spot.[5] + +Were it only on the fact of reproduction, I would be contented to take my +stand that the force of life is the indwelling power of pestilential +matter. Reproduction is a law of nature, and the law of nature is the law +of God. And where do we find He prevaricates with us? The more we study His +laws the more harmony and perfection we find; what is seeming confusion in +the ignorance of to-day, is order in the knowledge of to-morrow. If any one +ignorant of the law which regulates the diffusion of gases were {20} told +that a heavier gas would ascend contrary to its specific gravity through +the septum in a vessel containing a lighter gas above the heavier, he would +naturally doubt your assertion, and say, "that is contrary to the law of +gravity;" but explain to him the principle by which this comes about, and +the objects of the law; the order and beauty of the design become manifest. +But this is no equivocation, it is evidence there, that subordinate laws +exist and nothing more. It has never been found that men have gathered +"grapes of thorns and figs of thistles," nor has it ever been discovered +that inanimate matter multiplies itself. The seed of disease "is within +itself," multiplying and propagating itself; whether it formed a part of +creation at the beginning or not, is rather a question to be solved by +divines than physicians. When we know, however, the latency of seeds and +even of entire plants, and that they may be dried and remain so for years +yet being brought again into conditions adapted to their active existence, +they, as it were, revive from their sleep, and renew again their +reproductive properties: can we wonder if, in the great scheme of nature, +existences new to mankind should make their appearance? When the New +Zealander saw the surface of his ground producing to him unknown plants, +and the skins of his children generating peculiar eruptions, and each +propagating its kind, would he look, think you, to the wood or the stones, +the air or the water,--for the solution of the {21} mystery? No, he would +naturally say these people brought the _seeds_ with them. From the property +of reproduction possessed by these forms of matter, we infer the value of +the proposition. + + * * * * * + + +{22} + +CHAPTER II. + +THE NUMBER AND VALUE OF FACTS TO SUPPORT THE PROPOSITION. + +-------- + +SECTION I. + +ON REPRODUCTION. + +It is inferred that the proposition, "_the matter which operates in the +production of Epidemic, Endemic, and Infectious Diseases, possesses the +property of vitality_," we proceed now to the enumeration of those facts +which further elucidate this subject. + +The facts must necessarily be such as illustrate the identity of properties +in the imaginary germs, that are known to exist in demonstrable germs: we +take therefore the law of reproduction to be to life, what the law of +attraction is to gravitation.[6] + +{23} + +But further; do those matters which engender disease furnish to our minds +the properties inseparable from life in the abstract? Though the faculty of +reproduction is essentially an evidence that the thing which reproduces its +kind must be a living body, yet it is only a property or power of living +beings and is not itself life, it therefore is necessary to establish the +fact that the _materies morbi_ not only has the power of reproduction, but +also those properties which in the abstract will prove as far as +demonstration can go, that it has the essential properties common to all +living bodies. + +I must again quote from Coleridge, he says: "By life I every where mean the +true idea of life, or that most general form under which life manifests +itself to us, which includes all its other forms. This I have stated to be +the _tendency to individuation_ and the degrees or intensities of life, to +consist in the progressive realization of this tendency. The {24} power +which is acknowledged to exist wherever the realization is found, must +subsist wherever the tendency is manifested. The power which comes forth +and stirs abroad in the bird, must be latent in the egg." + +The tendency to individuation cannot be more strongly marked than in the +simple experiment of vaccination: we insert a small particle of the +so-called vaccine lymph under the skin, and by this means we multiply to an +enormous extent, the power which, in the first instance, we had in the form +of minute corpuscles in a dry and apparently inert state; nevertheless, +though in this condition there must have existed the tendency to +individuation or multiplication of individual existence, and the germs are +here to their active existence, as seen in the development of the vaccine +vesicle, what the egg is to the bird,[7] as described above; we may, +therefore, say that the power which exhibits itself in the production of a +vaccine vesicle, must have been latent in the dried matter. It is the +opinion of Muller that the entire vital principle of the egg {25} resides +in the germinal disk alone, and since _the external influences which act on +the germs_ of the most different organic beings are the same, we must +regard the simple germinal disk, consisting of granular amorphous matter, +as the potential whole of the future animal, endowed with the essential and +specific force or principle of the future being, and capable of increasing +the very small amount of this specific force and matter, which it already +possesses, by the assimilation of new matter. + +After speaking of inanimate objects, Dr. Carpenter says; "and what compared +with the permanence of these is the duration of any structure subject to +the conditions of _vitality_? _To be born_, to grow, to arrive at maturity, +to decline, to die, to decay, is the sum of the history of every being that +lives; from man, in the pomp of royalty, or the pride of philosophy, to the +gay and thoughtless insect that glitters for a few hours in the sunbeam and +is seen no more; from the stately oak, the monarch of the forest through +successive centuries, to the humble fungus which shoots forth and withers +in a day." + +To be born, signifies the faculty of reproduction existing or having +existed in an antecedent being to that one born, and also that itself +possesses equally a like power. To be born, is the first expression which +must be used in speaking of the faculties or properties of living beings as +independent existences, the annual formation of buds, trees, and shrubs, is +a multiplication of the species; the coral {26} and various budding polypes +increase by this process, indeed what is the seed of a plant, or the egg of +a bird, or the ovum of mammalia, but cast off buds; in all, the new being +was originally a portion of its parent, and if we examine the ovary of the +vegetable, the bird, or the mammal, can we find any expression more fitting +to designate the process than that of budding. To be born then, is the +evidence of an act of one living being, and the commencement of a series of +vital phenomena in another, but all these are subsequent to reproduction, +and constitute another chain of vital acts, all tending to a similar +result, the multiplication of the species.[8] + +Now, whether we apply the philosophical language of Coleridge, or the +language of observation of Muller, in confirmation of the doctrine here +inculcated, we arrive at the same point. + +Do we not witness in the newly formed vaccine vesicle, an increase of the +specific force and principle? We certainly have acquired by the process of +vaccination a manifold multiplication of power, and is there not also +assimilation of new matter in {27} which this power resides? And does not +every particle of this new matter contain within itself the same force and +principle, as existed in that which generated it? + +"We revert again to potentiated length in the power of magnetism +(reproduction); to surface in the power of electricity, and to the +synthesis of both or potentiated depth in constructive, that is chemical +affinity."[9] + +Some may be at a loss to conceive, at first, how irritability may be +considered a property of all vegetable matter; that it does exist in some +vegetables is certain, but that it does exist in all living beings is +equally certain;[10] the term, however, which would appear more appropriate +when that irritability does not exhibit itself in an appreciable form, is +_impressibility_. Irritability, as commonly understood, is seen in its +highest condition in muscular tissue; but "the irritable power and an +analogon of voluntary motion first dawn on us in the vegetable world in the +stamina and anthers at the period of {28} impregnation."--"The insect world +is the exponent of irritability, as the vegetable is of reproduction." + +The property of irritability attains its acme in man, the most highly +organized of all beings; and its gradations pass downwards through the +whole scale of animate creation; not so reproduction, for this faculty +observes the very opposite direction, for in plants a single impregnation +is sufficient for the evolution of myriads of detached lives. + +Reproduction is a fact, it is an essential property of life, and is a +reality to us from observation; but irritability is not so tangible and +demonstrable a property. We nevertheless may assume its universality, from +the circumstance that we lose sight of it by imperceptible degrees; the +irritability of the sensitive plant is as much irritability as that of the +highly organized muscle; but because the faculty evades our perception, "in +tapering by degrees, becoming beautifully less," we have no reason for +pronouncing its total extinction at any one point of the vegetable +kingdom,[11] any more than we should have {29} in saying that we see the +end of the earth, when describing the extent of our vision as we stand on +the sea shore. The extreme limit of our vision is the tangent of the circle +in reference to our visual organs; but how many tangential points there may +be beyond, it is impossible to say without knowing the dimensions of the +circle. + +I think we are now in a condition to assume, as far as abstraction will +conduct us without proceeding to an extreme length, that the _materies +morbi_, or, as I will now call them for the sake of clearer distinction, +_semina morbi_, possess those properties which in the abstract are common +to all living beings. + +Another argument strikes me as capable of adding further strength to the +proposition. We need but be told that a small piece of iron was placed in a +certain position with regard to another piece of iron, and that the smaller +piece moved through a given space and became attached to the larger, to +infer that magnetic force was in operation. Supposing this magnet then to +be folded in paper, and that it {30} be promiscuously placed near a +compass, the deflection of the needle would indicate that some object in +the vicinity was the cause of the deflection; we may farther try what +positions the needle takes by varying the position of the packet, and thus +point out which is the north and which the south pole of the screw of +paper. If we may consider attraction then to be to gravitation what +reproduction is to life, we do not err in saying in the one instance that +there is a living being, and in the other there is a magnet. + +The nebular theory, from which some astronomers made the foundation of many +speculations, came with so much interest to our minds that the fascination +could not be resisted. It was most delightful to revel in the imagination +that we possessed a key to the mode of formation of the starry hosts, and +when speculation had taken its extreme limits in the "Vestiges of the +Natural History of Creation," and the nebulae had served as the ground work +of a gigantic scheme, Lord Ross's monster telescope swept the heavens of +its cobwebs. We can imagine this great promoter of science saying to us, +Gentlemen, the clouds which have obscured you, are composed of myriads of +stars, and comprise systems as vast and as luminous as our own, had you but +power of vision to discern them. A new light thus appeared to philosophers, +and though no great practical results may flow from the discovery, it is +instructive from the fact that the imperfectly aided or unaided vision, +should not limit legitimate {31} inference. The nebulae before Lord Ross's +discovery were to the astronomer what the materies of epidemic and +infectious disease are to medical men. In the absence however of a giant +microscope to reveal such great truths, we may yet dimly shadow them by the +light of our reason. It was predicted in 1849 that minute vegetable germs, +in all probability all of the same type, were the agents producing epidemic +and infectious disease. In 1850, Mr. Oke Spooner says,[12] "On examining +the matter of Small {32} Pox and Cow Pox in every stage, he finds its +essential character to consist of a number of minute cells not exceeding +the 10,000th part of an inch in diameter: being about one-fourth smaller +than the globules of the blood, containing within their circumference many +still more minute nuclei, and presenting beyond their circumference +bud-like cells of the same size and character as those contained within the +circle." + +Should these observations made by Mr. Spooner turn out to be correct, they +will but fulfil my anticipations. Then again shall we see the same +application of imperfect vision to the limitation or temporary obstruction +of solid and determinate knowledge. + +We may reasonably expect that these bodies, discovered by Mr. Spooner, +should be the elementary matters of disease. Their existence was predicted +from the probability that living matter must be the agent; moreover, that +this matter when discovered {33} would be cellular, most probably +resembling the yeast plant as described by Mr. Spooner. + +It was predicted that a planet would be discovered in a certain position in +the heavens, because the perturbations of a comet indicated an attracting +body in the path of the eccentric wanderer; the prediction and the +fulfilment were almost simultaneous. + + * * * * * + +{34} + +SECTION II. + +HISTORICAL NOTICE OF EPIDEMIC DISEASES. + +The earliest notices we have of Pestilences are contained in Holy Writ. The +plagues which smote the Egyptians in the time of Moses are not unworthy +some comment here. Of those ten plagues, four out of the number were due to +the miraculous appearance of myriads of the lower animal tribes, in three +instances of insects,[13] viz. lice, flies, and locusts; in the fourth, +when Aaron stretched forth his hand with his rod over the streams, over the +rivers, and the ponds, frogs came up and covered the land of Egypt. In +these instances living beings are made the instruments in God's hand for +the punishment of the wicked. These plagues include the second, third, +fourth, and eighth. The first plague is mentioned as a conversion of the +waters into blood. Now if we may take this expression as being literal, +there is no reason to suppose that this blood differed in any respect from +ordinary sanguineous liquid; we therefore may assume, as the blood is every +where in Scripture spoken of as the _life_, that this fluid was endowed +with vital properties. + +{35} + +The fifth plague is described as a murrain among beasts; and the sixth, as +exhibiting itself as "a boil breaking forth with blains, upon man and upon +beast."[14] Now these affections bear a resemblance to the diseases known +to us at the present day through authentic records. The Black Death of the +14th century affords in its history but too awful a picture of the horrors +of such pestilences. In the tenth plague, the smiting of the first-born, we +are not told by what means it was brought about; but we have something even +here to lead us to conjecture. In the second visitation of the Black Death, +there were destroyed a great many children whom it had formerly spared, and +but few women. The seventh plague of hail is within our conception; as is +also that of darkness, the ninth plague. + +It is not a little remarkable that of the ten plagues, seven of them +depended upon agents intelligible to our comprehension; we can conceive of +{36} the invasion of a country by myriads of loathsome insects and +reptiles, and can imagine the wrath of an offended Deity directing the +force of a supernatural storm of hail upon a disobedient people; and we can +conjecture, though faintly, the consternation of human nature on being +subjected to a total darkness of three days' duration, when we consider +_that_ darkness has been described, as "a darkness that might be felt." + +From this abstract we discover that the three plagues whose causes we +cannot understand, or rather upon which no light has been thrown by +Scripture, bear analogies to those which we recognise, in the writings of +modern authors, as fearful pestilences. + +It is now our province to reflect on the causes supposed to be in operation +in the three instances, which become naturally separated from the rest. + +We are told that a murrain appeared among the cattle, without any +preliminary step. When the blains broke out upon man and beast, Moses had +been previously directed by the Almighty to take handfuls of the ashes of +the furnace, and sprinkle them towards the heaven in the sight of Pharaoh. +"_And it shall become small dust in all the land of Egypt_, and shall be a +boil breaking forth with blains upon man and upon beast, throughout all the +land of Egypt." + +Another coincidence, in connexion with subsequent pestilences, arrests the +attention, on the subject of the mysterious appearance on these occasions +of {37} matter resembling dust being prevalent about the houses, and on the +clothes of the people. Clouds also, and showers of dust-like particles, +were not of infrequent occurrence. Indeed, in the summer of 1849, during +the progress of the Cholera, several phenomena of a similar nature were +observed and authenticated; I myself can bear testimony to one instance of +the kind. It was observed by many persons in my neighbourhood after the +passage of an ominous and lurid cloud, that as they walked their clothes +became covered with a singular dust-like matter of very peculiar +appearance. That this phenomenon was not destitute of significance may be +gathered from the fact, that on the night of that day several severe cases +of Cholera occurred, though our village had been comparatively free for ten +days. + +Hecker, in writing on the Black Death says, the German accounts expressly +speak of a "thick stinking mist which advanced from the east,[15] and {38} +spread itself over Italy; there could be no deception in so palpable a +phenomenon." It is not unworthy of mention, that in the East successive +invasions of locusts "which had never perhaps darkened the sun in thicker +swarms," preceded the great outbreak of this disease, for they left famine +in their train. + +From 1500 to 1503 in Germany and France, during the prevalence of the +sweating sickness, spots of different colours made their appearance, +"principally red, but also white, yellow, grey, and black, often in a very +short time, on the roofs of houses, on clothes, on the veils and +neckerchiefs of women, &c." Blood rain is also mentioned as having occurred +at this time, which consisted of the aggregation of minute particles of red +matter. + +In the seven plagues, miraculous operations of the Deity consisted in the +unusual manifestation of phenomena, but which in their effects are +recognizable as of clear and definite import. The miracles here are,--in +the _mode_ of producing the swarms of frogs, locusts, &c. but they are +manifest and unmistakeable _causes_ of plague and famine; in the other +three, on the contrary, we witness only the effects, the causes are hidden +from us; we may, therefore, as in current events, legitimately investigate +the subject, and what better course can be adopted than that which +classifies the traditionary past with all subsequent history. Presuming +such a method of research to be admitted, I have assumed that as {39} the +_causes_ of the seven plagues have been distinctly given, the others, +though only mentioned in their effects, were due to causes of a nature in +some way to be compared with their concomitants, that is to say, if a +special intervention of the Deity brought about a miraculous appearance of +frogs, lice, &c. there is but little reason to doubt that some other agent +was miraculously multiplied and concentrated to induce the murrain, +engender the blain, and smite the first-born: as if to lead us into this +enquiry, on the visitation of the blain in man and beast, the Bible History +tells us that Moses threw ashes of the furnace, which became a dust +throughout all the land of Egypt; we cannot imagine that this simply as +ashes could have caused the blain, we may conclude that by some special +miracle, either the ashes were converted into a specific form of matter +capable of inducing the effects recorded, or that an independent septic +matter was generated for the purpose. If the latter, the act of throwing +the ashes of the furnace into the air may have been intended to signify +that the extremely minute division of the particles when thus cast into +space, typified the inscrutable and hidden nature of the matter endowed +with such marvellous properties.[16] + +{40} + +Further on in the book of Leviticus are passages which I cannot forbear +transcribing, for they point out to us most indubitably a line of enquiry +in reference to diseases of a contagious nature. + +"The garment also that the plague of leprosy is in, whether it be a woollen +garment, or a linen garment, whether it be in the warp or woof, of linen or +of woollen, whether in a skin, or in any thing made of skin, and if the +plague be greenish or reddish in the garment ... it is a plague of leprosy, +and shall be shewed unto the Priest, and the Priest shall look upon the +plague and shut up it that hath the plague seven days; and he shall look on +the plague on the seventh day; if the plague be spread in the garment, +either in the warp, &c. ... the plague is a fretting leprosy, it is +unclean. He shall therefore burn that garment ... wherein the plague is, +for it is a fretting leprosy; it shall be burnt in the fire. And if the +Priest shall look, and behold, the plague be not spread in the garment ... +then the Priest shall command that they wash the thing wherein the plague +is, and he shall shut it up seven days more: and the Priest shall look on +the plague, after that it is washed: and behold if the plague have _not_ +changed his colour, and the plague be not spread, it is unclean; thou {41} +shalt burn it in the fire; it is fret inward; whether it be bare within or +without. And if the Priest look and behold the plague be somewhat dark +after the washing of it, then he shall rend it out of the garment ... and +if it appear still in the garment either in the warp or the woof ... it is +a spreading plague: thou shalt burn that wherein the plague is with fire. +And the garment ... which thou shalt wash, if the plague be departed from +them, then it shall be washed the second time and shall be clean."--Chap. +xiii. 47-58. + +Again in Deuteronomy. The curse for disobedience: "The Lord shall make the +pestilence cleave to thee until he have consumed thee from off the +land.--The Lord shall smite thee with a consumption, and with a fever, and +with an inflammation, and with an extreme burning, and with the drought, +and with blasting, and with _mildew_, and they shall pursue thee until thou +perish.--The Lord shall make the rain of thy land _powder_ and _dust_: from +heaven shall it come down upon thee until thou be destroyed." + +It may be said, and I doubt not will be said, all this is unnecessarily +dragging the sacred volume into an enquiry totally foreign to its general +tenor; on the contrary, however, I maintain by that Book we are to learn +the ways of God to man, and further, that no study can impress mankind with +so awful, so terrific an idea of his responsible position, as that which +leads him into the investigation of the causes {42} by which the Almighty, +doubtless in His wisdom, has thought fit at various epochs of this world's +history, to place man face to face with pestilence, famine and sudden +death. + +There is no man would less willingly than myself introduce profanely the +revelations of Scripture. The observations here made are not, therefore, +intended for light or heedless controversy; if they have a significance of +any import, let them be alluded to in the same spirit with which they have +been quoted; if they convey nothing for approval to the reader, let silence +rest upon them. To those who would fain disregard my request, let me recall +to their minds the veneration which from childhood I trust we have always +felt on hearing or seeing those two words--Holy Bible. + +It is yet to be determined, whether the greenish or reddish appearance of +the garment spoken of, as being contaminated with the plague of the leprosy +had any specific relation to the disease itself. The priest orders that the +garment shall be shut up seven days, and on the seventh day, if the plague +be increased, by which, of course, is meant if the greenish or reddish +colour have increased, and from which we may gather that a power of +spontaneous increase was possessed by the matter, such a result indicated a +fretting leprosy, and the garment was to be burnt. Again, though there may +have been no increase, but a persistence of the coloured matter after +shutting up and washing the garment, it is to {43} be burnt, for it is fret +inward, signifying, that the germs of the affection are still there, and +may soon increase. Other rules follow in reference to the plague of +leprosy, and the mode of deciding whether an article be unclean or clean is +definitely laid down, but our purpose is served in mentioning the above, to +shew that in the time of Moses the spontaneous increase of certain minute +multiplying germs was supposed to have a close connexion with disease. It +is equally clear, that the priests were aware by the order given them, that +if the ordinary modes of purifying articles of clothing failed in their +effect, the safest and surest method of destroying infectious matter was to +resort to the practice of consuming by fire all materials capable of +propagating an infectious malady. + +The facts above noticed, accurately correspond to what we now know as +applicable to the matter of infectious and contagious maladies. It is a +rule, I believe universally adopted throughout the Poor-houses of this +country, to put the clothes of all persons about to become residents in +these establishments, into ovens, where they are submitted to a temperature +incompatible with the existence of either animal or vegetable life. By this +means all living matters are destroyed, but the fabrics and inorganic +matters retain their properties intact. This simple proceeding, I am +credibly informed, is an effectual preventive of contamination by articles +of clothing, a desideratum of no small importance, when it is {44} +remembered that the diseases among the poor owe much of their inveteracy to +the accumulation of effete organic matters about their persons and clothes. + +A few more observations are called for on the quotation from Deuteronomy, +in which allusion is made to living matter being an agent in the production +of disease. In the curse upon the children of Israel for disobedience, we +read that they are to be smitten with mildew. No further information, +however, is vouchsafed to us, nevertheless, we can conceive the wretched +condition of those on whom the curse might fall. Again, we find in a +continuation of this curse that the Almighty uses means such as He adopted +in the sixth plague of the Egyptians. The ashes of the furnace became a +small dust in all the land of Egypt, breaking forth with blains upon man +and beast. In the curse of the Israelites the words are: "The Lord shall +make the rain of thy land _powder and dust_: from Heaven shall it come down +upon thee until thou be destroyed." + +It might be conjectured that the absence of rain would be sufficient to +account for the extinction of the people on whom the curse was pronounced, +by the famine and drought necessarily attendant upon the loss of moisture. +But this does not appear to be the meaning of the passage, for the powder +and dust are mentioned as the agents of destruction; besides, in the +continuation of the curse, the locust is to destroy the grain, the worm the +grapes, and {45} the olive is to shed his fruit; we may thus take for +granted that drought and famine are not to be caused by the showering of +powder and dust, it must consequently be supposed that the effects of the +dust in the instance of the Egyptians are to be compared and classified +with those of the dust which smote the Israelites. + +As far then as Sacred History conducts us in the enquiry, concerning the +causes of pestilences, we gain encouragement in the belief that living +germs are the active agents, for in the case of the leprosy, we have +evidence of reproduction in connexion with infection, which, if our line of +argument be tenable, amounts to demonstration; then, in the other instances +of the plagues, by boils and blains, they distinctly bear comparison with +the accounts given by profane writers, of the visitations of pestilences on +the earth, subsequently to those mentioned in Scripture history. + +This leads now to the consideration of recorded facts observed and noted +during the various Epidemics in the early and subsequent periods of Man's +History, as given by those on whom reliance may be fairly placed. + +Setting aside the uncertain information contained in the writings of the +Chinese,[17] a people whose {46} progress in the science and practice of +Medicine has nothing to commend it (even as it is at the present day) to +the notice either of the physician or the historian, unless it be to the +latter as a mark of peculiarity both in a social and political point of +view,--passing also over the Egyptians, the Arabians, and the Greeks,--and +even Hippocrates himself, we are driven to the Romans for any authentic or +precise notice of Epidemic Affections. It has been attributed to +Hippocrates that he predicted the appearance of the Plague at Athens, {47} +and that when it was introduced into Greece he dispelled it, "by purifying +the air with fires into which were thrown sweet-scented herbs and flowers +along with other perfumes."[18] But little advantage can be derived from +enquiries concerning the first appearance of any disease, for the +probability of discovering the primary cause is certainly a {48} hopeless +case, if attempted by means of the writings of ancient authors, when it is +recollected that with all the science and learning of the ancient +Egyptians, the use of optical instruments was not comprised among the +paraphernalia of their arts. The knowledge that was limited to the powers +of natural vision, where the foundation of knowledge is based upon facts +obtained through the aid of that penetrator of nature's secrets, the +microscope, offers no advantages to the student of the present day. + +To say that a disease commenced in the East and travelled westward, and at +length found a habitation and a name in every part of the globe, is no more +than to say that disease is coeval with the fall of man. The cause is as +much hidden in the region of its birth, as in that where it sojourns for a +time. The cause of the sweating sickness was as much a mystery in England +as in all the other nations of Europe, which were visited by its +devastating power. And these observations apply with as much force to one +disease as another; for even our indigenous ague, originating in some +places so limited that the shadow of a passing cloud may mark the boundary +of its dwelling place, as inscrutably evades our vigilance, with all the +appliances that art can bring to our assistance, in endeavouring to evoke +its extraordinary properties under the cognizance of our senses. + +If we weigh the air which carries the poison, or analyze it by the most +delicate chemical tests, or {49} take the weight of the atmosphere which is +charged with it, or if we take the blood which carries the germs of the +disease to the tissues of the body, and submit them after the work of +destruction is accomplished, to the most rigid inspection, we can but +exclaim, + + "These are Thy marvellous works!" + +and confess our total inability to fathom the unbounded. + +If then no practical advantage can accrue from investigating the writings +of the ancients on these subjects, beyond comparing their historical +statements with those of more recent date, our purpose will be served by +occasionally embodying any remarkable observations of the former with those +of the latter. + +In proceeding with this course it were better to confine our minds chiefly +to two diseases which appear from history to have been known from the +earliest periods, these are the Plague and the Small Pox, mentioning other +diseases only _en route_. + +Passing then, to the sixth century of the Christian era for the first +distinct and connected account of the Plague, it appears from a host of +testimony, that the history of this disease, as given by Procopius, well +merits our attention. Drs. Friend and Hamilton, in their Histories of +Medicine, and Gibbon, in his History of Rome, are equally warm in their +praise of Procopius: the latter says, he "emulated the skill and diligence +of Thucydides in the {50} description of the Plague at Athens." The account +given by Procopius of this disease, does not differ materially from that +given by subsequent eye-witnesses of similar pestilences. Its point of +origin is clearly marked, and its mode of dispersion in all directions +distinctly traced from "the neighbourhood of Pelusium, between the +Serbonian bog and the eastern channel of the Nile." It commenced in the +year 542. It raged in Constantinople in the following year, and it was in +this city that our historian gathered the materials which are handed down +to us. When, however, we anxiously look for any explanation as to the cause +of the malady, we are told that it must have been a direct visitation from +Heaven, in consequence of the eccentric characters exhibited in its +wide-spreading influence, in not yielding to the scrutiny nor bending to +the laws known to prevail, and to regulate the course of other diseases: +neither country nor clime, age nor sex, the strong and healthy, nor the +weakly and previously diseased, could be said to be free from its +indiscriminate destruction. + +But some phenomena preceding the outbreak of the pestilence are observed as +coincidences by all authors. Gibbon thus writes: "I shall conclude this +chapter with the comets, the earthquakes, and the plague which astonished +or afflicted the age of Justinian." From the accounts given by this author, +earthquakes for some years had been threatening and destroying many +portions of the globe, {51} that in the ruins of cities and in the chasms +of the earth, great was the sacrifice of human life. Constantinople, which +suffered so severely from the plague is said to have been shaken for forty +days. These great disturbances of the globe have been always looked upon as +indicating other and important influences of a secret or hidden nature; +these impressions on the minds of the people are traceable throughout the +histories of all epidemics, and have been sufficiently distinct among the +people of our own time, preceding and during the period of infliction. + +From this short notice of the Plague of 543, I pass to the ninth century, +when Rhazes, the Arabian physician, endeavoured to enlighten the world on +the subject of Small Pox.[19] In quoting his opinions, I am not to be +understood as subscribing to them, but merely endeavouring to point out +some peculiar and interesting observations. + +First, then, Rhazes attributes the disease to a condition of the blood, +which he thus describes, to shew how it happens that in infancy and +childhood the disease is most prevalent, and that old age is {52} least +liable to the affection.[20] "The blood of infants and children may be +compared to _must_, in which the coction leading to perfect ripeness has +not yet begun, nor the movement towards fermentation taken place; the blood +of young men may be compared to must which has already fermented and made a +hissing noise, and has thrown out abundant vapours and its superfluous +parts, like wine which is now still and quiet, and arrived at its full +strength, and as to the blood of old men, it may be compared to wine which +has now lost its strength, and is beginning to grow vapid and sour." + +"Now the Small Pox arises when the blood putrifies and ferments, so that +the superfluous vapours are thrown out of it, and it is changed from the +blood of infants which is like must, into the blood of young men which is +like wine perfectly ripened: and the Small Pox itself may be compared to +the fermentation and the hissing noise which take place at that time." + +But the cause of the disease is simply alluded to by this author, as +depending upon "occult dispositions in the air," and as he speaks here of +Measles with the Small Pox he goes on to say--"which necessarily cause +these diseases and predispose bodies to them." This notion of Rhazes that +there is some peculiar condition of the blood which favours a process +resembling fermentation is not without interest. The circumstance that +individuals are not {53} usually liable to a second attack of the disease, +no doubt directed the attention of this physician to compare the process of +fermentation with disease of such a nature, seeing that when the whole of +the saccharine matter was converted into spirit, the hissing noise, as he +calls it, or the disengagement of carbonic acid gas would cease, and the +capacity for fermentation be entirely gone. So that the occult conditions +of the air, their power of inducing a disease, and multiplying the matter +capable of engendering a similar affection, stood in the mind of Rhazes as +analogous if not identical phenomena. + +We pass now without further comment to the epidemics of the Middle Ages; +and here the work of the philosophical Hecker leaves us little else to +desire in the way of information, as far as it is obtainable from published +records. From the manner in which he has grouped the facts which presented +themselves to his mind in the course of a most laborious research, he has +saved the student of this subject much toil in acquiring matter for +reflection; he has here but to read and digest. + +I know not how to select from this invaluable work the most striking +passages, to strengthen and support my hypothesis, for not a page is +destitute of facts corroborative of the doctrine that vital germs are the +material agents of pestilential disorders. The opening paragraph to the +Black Death is a most cogent illustration of the assertion; it is, as it +were, the theme of the work. "That {54} Omnipotence, which has called the +world with all _its living creatures into one animated being_, especially +reveals himself in the desolation of great pestilences. The powers of +creation come into violent collision; the sultry dryness of the atmosphere; +the subterranean thunders; the mist of overflowing waters are the +harbingers of destruction. Nature is not satisfied with the ordinary +alternations of life and death, and the destroying angel waves over man and +beast his flaming sword." + +I must here apologise for large transcripts from Hecker's work, for neither +could I command the amount of knowledge there displayed, nor use such +appropriate language as the learned translator has employed. + +It is not doubted that the Black Death was an Oriental plague, only of more +than usual severity, and wider spread influence of the infectious nature of +this disease, and the active properties of the matter producing it. Hecker +says, "articles of this kind--bedding and clothes--removed from the access +of air, not only retain the matter of contagion for an indefinite period, +_but also increase its activity, and engender it like a living being_, +frightful ill consequences followed for many years after the first fury of +the pestilence was past."[21] + +{55} + +As extraordinary atmospheric and telluric phenomena preceded the Plague in +the time of Justinian, so do we find similar instances recorded as the +precursor of a similar visitation 700 years later. I am concerned more with +those circumstances which refer more especially to my subject, _viz._ the +development of organic matter, and the peculiar odours of the atmosphere, +the latter being evidence of some foreign and unusual production in our +respiratory media. "On the island of Cyprus, before the earthquake, a +pestiferous wind spread so poisonous an odour, that many being overpowered +by it, fell down suddenly and expired in dreadful agonies. A thick stinking +mist advanced from the east, and spread itself over Italy." + +{56} + +It is probable that the atmosphere contained foreign and sensibly +perceptible admixtures to a great extent, which, at least in the lower +regions, could not be decomposed or rendered ineffective by separation. In +1348 an unexampled earthquake shook Greece, Italy, and the neighbouring +countries. During this earthquake the wine in the casks became turbid, a +proof that changes causing a decomposition of the atmosphere had taken +place. "The insect tribe was wonderfully called into life, as if animated +beings were destined to complete the destruction which astral and telluric +powers had began." + +"The corruption of the atmosphere came from the east, but the disease +itself came not upon the wings of the wind, but was only excited and +increased by the atmosphere where it had previously existed." + +"The most powerful of all the springs of the disease was contagion; for in +the most distant countries, which had scarcely yet heard the echo of the +first concussion, the people fell a sacrifice to organic poison, the +untimely offspring of vital energies thrown into violent commotion." + +"After the cessation of the Black Plague, a greater fecundity in women was +every where remarkable, a grand phenomena, which from its occurrence after +every destructive pestilence, proves to conviction the prevalence of a +higher power in the direction of general organic life." {57} + +In the article Contagion, of the Essay, Sweating Sickness: "Most fevers +which are produced by general causes, propagate themselves for a time +spontaneously." "The exhalations of the affected become the germs of a +similar decomposition in those bodies which receive them, and produce in +these a like attack upon the internal organs, _and thus a merely morbid +phenomenon of life, shows that it possesses the fundamental property of all +life, that of propagating itself in an appropriate soil. On this point +there is no doubt, the phenomena which prove it have been observed from +time immemorial, in an endless variety of circumstances, but always with a +uniform manifestation of a fundamental law._" + +Mead, in his Essay on the Plague, makes many observations of great interest +and worthy a physician of eminence; and where, in recent times, shall we +look for any more definite information concerning the causes of +pestilences? It is not a little singular that at the time this book was +published, it was read with such avidity that it went through seven +editions in one year.[22] From this circumstance we may gather that the +public generally took a lively and proper interest in a subject that was +not only of domestic, but national importance. Whether this interest was +stimulated by the fact that the work was written expressly by order of the +{58} government, it is now impossible to say, at any rate much credit is +due to the Lords of the Regency for having placed so important a duty upon +one so thoroughly and in every way so duly qualified for the task as Dr. +Mead. It had been well if some of the advice given at that time, as means +of protection against the Plague, had been applied and put in force during +the late visitation of epidemic Cholera, for, however the minds of some may +be convinced of the non-contagiousness of Cholera, there are many who hold +a different opinion, and all will acknowledge, that if not strictly a +contagious affection, it is clearly proved to be capable of being carried +from place to place, or to use Dr. Copland's words, it is "a portable +disease." But this is not the place to discuss the subject of contagion, +allusion will be made to it hereafter. To return, Mead's expressions are +singularly illustrative of the vital power possessed by the germs of +disease; he says, "There are instances of the distemper's being stopt by +the winter cold, and yet the seeds of it not destroyed, but only kept +unactive, _till the warmth of the following spring has given them new life +and force_. His confession as to the hidden cause of the disease, is worthy +transcribing: "We are acquainted too little with the laws, by which the +small parts of matter act upon each other, to be able precisely to +determine the qualities requisite to change animal juices into such +acrimonious humours, or to explain {59} how all the distinguishing symptoms +attending the disease are produced."[23] + +On the spread of the Plague is the following:--"The plague is a _real +poison_, which being bred in the southern parts of the world, maintains +itself there by circulating from infected persons to goods, that when the +constitution of the air happens to favour infection, it rages with great +violence." Contagious matter is lodged in goods of a loose and soft +texture, which being packed up, and carried into other countries, let out, +when opened, the imprisoned seeds of contagion, and produce the disease +whenever the air is disposed to give them force, "otherwise they may be +dispersed without any considerable ill effects." Gibbon thus speaks of the +above quoted work: "I have read with pleasure Mead's short but elegant +Treatise concerning Pestilential Disorders;" many also might read it at the +present day with infinite advantage. Mead most satisfactorily combats the +opinions of the French physicians who maintained the non-contagiousness of +the Plague. Experience proves beyond doubt, that certain conditions of +atmosphere, of {60} which we are ignorant, favour the growth and increase +of pestilences as they do of all vegetation. + +Dr. Bancroft was of opinion that specific contagions are each and severally +creatures of Divine Wisdom, as distinctly and designedly exerted for their +production, as it was to create the several species of animals and +vegetables around us. + +The indigenous fever of Ireland, which has several times shewn itself in an +epidemic form, appears to have been as fatal, as the Plague in the South of +Europe. Its devastations have generally been associated or preceded by +famine and general distress. Dr. Harty, writing in 1820, says that thrice +within the last eighty years has the same fever appeared in its epidemic +character. In the year 1741 Ireland lost 80,000 of her inhabitants from +this cause. It is a maculated typhus, and considered to be a special +product of the Emerald Isle. It has been shewn that fever began to exceed +its ordinary rate in those places first where famine and want of employment +were most severely felt,[24] and that in such places and under such +circumstances, it was most prevalent and fatal. The physicians generally +believed it to have been spontaneously produced and not to have been +imported. In the last Famine Fever of Ireland, Liverpool and several other +places suffered severely from the {61} importation of their Channel +neighbours with the disease in some instances, and the infection in others +about their persons. Hitherto these have to all appearance been the limits +of the affection; we know not, however, how soon the time may come when the +invisible bonds which have thus chained the disease to certain localities +may be severed, and spreading itself like other pestilences in an +aggravated form, attack this country as a last and crowning act of +retributive justice. At present it has but cost us money and regrets, but +if the history of pestilences is to be heeded, there are many tokens which +seem to indicate that a few slight concurrent circumstances only are +wanting, to bring the full force of this disease upon us; then will there +be a sacrifice of life. Edinburgh and other towns of Scotland have had some +visitations already, ourselves but slightly, but let our labouring +population suffer to any large extent for want of work, and we shall +inevitably be the sufferers from that fever which in consequence of general +destitution is now always more or less prevalent in Ireland. + +The Sweating Sickness prevailed in England alone at first, but at length +sought foreign victims. The Cholera is an exotic disease, as well as the +Plague, but they occasionally have visited our shores, and their seeds +remain among us. The Small Pox is now even not known in some parts of the +world, but when once it is established, who can predict the period of its +first appearance in an {62} epidemic form. The history of the disease +informs us that in all the countries where it has been introduced, sooner +or later an epidemic has seized the inhabitants. + +A disease previously unknown in India appeared at Rangoon in the year 1824, +which obtained the name of Scarlatina Rheumatica. Four years afterwards it +attacked the Southern States of North America, and though the disease was +so impartial as scarcely to spare a single individual of any town to which +it extended its influence, it was not accompanied with that mortality which +has usually been the characteristic of wide spread epidemics. + +There is one peculiar feature of all epidemics which may be here mentioned +as indicative of some definite, though at present unaccountable cause, +operating in the sudden suppression of the disease after a certain period +of duration. This distinctive character may almost be considered as a law +in reference to these affections; if we take three distinct diseases, the +Plague, the Irish Fever and the Cholera, we find the rule apply to all. Of +the latter disease we have so recently been witnesses, that I need not +quote authorities on this point concerning it. In Dr. Patrick Russell's +work on the Plague at Aleppo I find the following remarkable passage. After +alluding to the great increase of pestilential effluvia that there must be +towards the close of an epidemic, compared with the amount at the onset of +the disease, and expressing his {63} astonishment that so many escape +infection, he says: "The fact, however unaccountable, is unquestionably +certain; the distemper seems to be extinguished by some cause or causes +equally unknown, as those which concurred to render it more or less +epidemical in its advance and at its height." He then mentions that in +Europe the sudden cessation may be partly attributable to the measures +adopted for preventing its extension; but "at Aleppo, where the disease is +left to run its natural course, and few or no means of purification are +employed, it pursues nearly the same progress in different years; it +declines and revives in certain seasons, and at length, without the +interference of human aid, ceases entirely." + +The expressions of Dr. Harty on this subject, in connexion with the Irish +Fever, would apply as well to all other epidemics: "It is a fact, that +though every diversity of management was resorted to for effecting the +suppression of the disease, yet, nevertheless, there was an almost +simultaneous and apparently spontaneous decline of the epidemic in the +various and most remote parts of Ireland. It is not an easy matter to offer +a satisfactory explanation of this circumstance, _some general cause must_ +no doubt have influenced the subsidence of the disease, yet that cause +could not be atmospheric, inasmuch as the decline, though it might be said +to be simultaneous, was not sufficiently so to admit of that explanation." + + * * * * * + +{64} + +SECTION III. + +THE DISPERSION OF PLANTS AND DISEASES. + +The dispersion of Diseases and the dispersion of Plants, exhibit analogies +which might be little expected, on a superficial view of the enquiry. + +We are led to believe, that the earth as a whole, was not covered with +vegetation in a day, the geological history of this planet is one of +development, and though at first sight this expression of opinion may +appear to savour of doubt in the Mosaic record, a more extended +acquaintance with the subject, favours rather and confirms Scripture +history. + +As the peopling of the earth has been a gradual process with the animal +creation, so has it been also with the vegetable kingdom. We see at the +present day, that plants by various means of transit from place to place, +multiply themselves on new soils and in new climes, the same with animals. +By other means we observe, or can trace, the extinction from various +localities and countries, of members of both the animal and vegetable +kingdom. + +We learn that originally this planet had a temperature much higher than at +present, and that the variation of temperature between the equator and the +poles, which we now witness, did not obtain in the earlier condition of the +globe. We are given to understand, and not without considerable proof, {65} +if not demonstration, that the earth was a vast bog, in which rank +vegetation grew, and in which the ichthyosauri and plesiosauri, must have +floundered about as unwieldy and loathsome bodies. We can readily conceive +a condition of atmosphere at this time to have been loaded with pestiferous +vapours of an organized nature; it is entirely in accordance with all we +know, that it should have been so. Allied forms of plants to those now in +existence, are found in the form of fossils, by which comparisons are made, +but how the transition into the present Flora took place, or at what +period, it is impossible to say. That these plants should have been +entirely destroyed during the revolutions of the earth by earthquakes, and +their consequences; the collection of waters into the vacuities formed, and +their draining off from other places by elevations of the land, is not to +be dwelt on without astonishment; then again the ultimate changes of +temperature on the surface of the earth, may have been another element in +the history of their extinction. But if we may be allowed to imagine that +there were organic germs floating in the vapours of the atmosphere, these +would hardly be subject to the same influences as those which depended +solely on their fixation to the soil for subsistence. The atmosphere, their +native element, being influenced by the commotions from below, would be +agitated; vortiginous currents would be established, hurricanes would sweep +over the stagnant pool and reeking morass, {66} and the higher regions of +the air might have thus given protection to these subtle germs, while +almost a total extinction of the elegant ferns, the stately palm, and the +towering cane was in course of procedure. Then when the strife of the earth +and elements had subsided, these would descend with the gentle breezes, and +again find in various spots a local habitation-- + + "Where blue mists, through the unmoving atmosphere, + Scatter the seeds of pestilence _and feed unnatural vegetation_." + +In the new era, when the earth took its present physiognomy, who shall say +whether much of the pestiferous matter may not have been enclosed and +condensed in the bowels of the earth, and when it is remembered, that +earthquakes and convulsions of nature,[25] have invariably preceded the +outbreak of {67} any great pestilences, that stinking mists, coming from +some unknown regions, and unusual vegetations have made their appearance in +concert at these times, what I ask is more natural than to imagine, that +they have been let loose during the general convulsion? It may be asked, +what is to be said about that revolution of the earth, when the great +Deluge spread over the whole face of the globe? It can only be replied, +that this is a part of the scheme of cosmogony into which we are not called +upon to enter. There are yet strenuous supporters of the partial as well as +total submersion of this planet, but whether it be true that the vast +torrents which appear to have swept the surface uniformly in a southern +direction, were of a date coeval with the deluge, and constituted an +essential portion of the phenomena, of which one was, that "the fountains +of the great deep were broken up," or whether they were anterior to this +catastrophe, will not at all interfere with the conjecture of a very early +formation and propagation of the germs of pestilential diseases, for the +commotions of a deluge were less likely to interfere with the vapours of +the atmosphere, than extensive volcanic and electric disturbances. +Moreover, it is rather in favour of this theory, that the {68} regions +where the temperature and exhalations most nearly resemble those of the +former condition of the earth, are those in which pestilential disorders +most frequently arise, and where their virulence has always been most +strongly marked. + +After the various commotions which left the globe, with its present +physiognomy of mountains, plains, valleys, rivers, lakes, and oceans; a new +Flora and Fauna appeared to adorn and animate the scene of man's existence. +Plants and animals were created apparently in adaptation to the numerous +climes, which the seasons in the various latitudes or the elevations of the +soil, were prepared to render fruitful and useful each in its own sphere. +Besides this, the plants of the same latitude, in some instances, differ +materially from each other; in this case it seems that the soil has much to +do with this peculiarity, for it is certain that the soil and the +contiguous atmosphere, have a close and intimate relation; the drought of +the desert depends upon the sand, as humid atmosphere is connected with the +morass. To illustrate the tendency which vegetation shews in appropriating +one locality more than another, I may quote the following: "Some of the +volcanic masses of the Aeolian or Lipari Islands, that have existed beyond +the reach of history, are still without a blade of verdure; while others in +various parts, of little more than two hundred years date, bear spontaneous +vegetation, and the same is seen on two lavas of Etna near each other, for +the one {69} of 1536 is still black and arid, while that of 1636, is +covered with oaks, fruit trees, and vines." + +In comparing the diffusion of plants, and the diffusion of diseases, the +different modes by which this generally has been effected may be considered +under heads, that the comparison may be more readily traced. + +_First_, seeds are diffused by the atmosphere, either by the prevalence of +certain currents, which are produced by known laws, in which case, no +difficulty occurs in the explanations; or in a more imperceptible manner, +as by those more uncertain atmospheric currents of a partial nature, which, +though they seem to have laws governing them, are not yet understood. + +_Second_, seeds are transported by water across oceans, &c. when they can +be floated on any material by which they are preserved, as by wrecks and +masses of wood, which have been washed down the rivers. + +_Third_, they are conveyed by man to all parts of the globe. + +_Fourth_, a period of latency is observed to apply to them, that is, they +require certain essential conditions before germination occurs; so that +even in some localities, a plant may not have been known to exist in a +particular neighbourhood, but by a train of circumstances, it may make its +appearance, and again be a centre of development. + +1st. I shall not here wander into the speculation, {70} whether plants had +originally one birth-place, as a centre from which they spread by various +agencies, as supposed by Linnaeus, nor into any enquiry beyond those facts, +which may fairly come within our own comprehension, and within our own +means of demonstration. + +Many seeds are provided with means adapting them for floating in the +atmosphere, these are by pappi, or winglets and hairs, but it cannot be +doubted that the agency of atmospheric currents, is productive of +considerable effects in the dispersion of lighter seeds, such as those of +mosses, fungi, and lichens--lichens have been discovered in Brittany, which +are peculiar to Jamaica, and Monsieur De Candolle concludes, that their +seeds had been carried thence by the south-westerly winds, which prevail +during a great part of the year on this portion of the French coast. + +But Humboldt's testimony on the subject of winds is most satisfactory, for +he says, "Small singing birds, and even butterflies, are found at sea, at +great distances from the coast (as I have several times had opportunities +of observing in the Pacific), being carried there by the force of the wind, +when storms come off the land." It is generally believed, from abundance of +proofs, that the trade winds, and other continuous currents, are means by +which plants are conveyed from one country to another.[26] + +{71} + +As to the partial currents, Humboldt further says, "The heated crust of the +earth occasions an ascending vertical current of air by which light bodies +are borne upwards. M. Boussingault, and Don Mariano De Rivero, in ascending +the summit of the Silla, one of the gneiss mountains of Caraccas, saw in +the middle of the day, about noon, whitish shining bodies rise from the +valley to the summit of the mountain, 5755 feet high, and then sink down +towards the neighbouring sea coast. These movements continued +uninterruptedly for the space of an hour. The whitish shining bodies proved +to be small agglomerations of straws, or blades of grass, which were +recognized by Professor Kunth, for a species of vilfa, a genus, which +together with agrostis, is very abundant in the provinces of Caraccas and +Cumana." + +On the plague of locusts we read, that "the Lord brought an east wind upon +the land, all that day and all that night, and when it was morning the east +wind brought the locusts." + +On the Black Death we read, "There were many locusts which had been blown +into the sea by a hurricane, and a dense and awful fog was seen in the +heavens, rising in the east, and descending upon Italy." + +Of the Plague of 542, Gibbon says, "The winds might diffuse that subtle +venom, but unless the atmosphere be previously disposed for its reception, +the plague would soon expire in the cold or {72} temperate regions of the +north. The disease alternately languished and revived, but it was not till +a calamitous period of fifty-two years, that mankind recovered their +health, or the air resumed its pure and salubrious quality." + +In the history of the Sweating Sickness, of which there were five distinct +visitations, we find ample allusions to the atmosphere, and the mode in +which the disease was conveyed by this medium. + +I quote again from Hecker: "It seemed that _the banks of the Severn_ were +the _focus of the malady_, and that from hence, a true impestation of the +atmosphere, was diffused in every direction. Whithersoever the winds wafted +the stinking mists, the inhabitants became infested with the sweating +sickness. _These poisonous clouds of mists were observed moving from place +to place_, with the disease in their train, affecting one town after +another, and morning and evening spreading their nauseating insufferable +stench. At greater distances, these clouds being dispersed by the wind, +became gradually attenuated yet their dispersion set no bounds to the +pestilence, and it was as if they had imparted to the lower strata of the +atmosphere, _a kind of ferment which went on engendering itself even +without the presence of the thick misty vapour_, and being received into +men's lungs, produced the frightful disease everywhere."[27] + +{73} + +Mr. K. B. Martin, harbour-master of Ramsgate, in a communication to Lord +Carlisle on the Cholera of last autumn, says, "At midnight of the 31st +August (1849), the Samson (steam-tug) proceeded to the Goodwin Sands, where +the crew were employed under the Trinity agent, assisting in work carried +on there by that corporation. While there, at 3 A.M. 1st September, _a hot +humid haze, with a bog-like smell_, passed over them; and the greater +number of the men there employed instantly felt a nausea. They were in two +parties. One man at work on the sand was obliged to be carried to the boat; +and before they reached the steam vessel at anchor, the cramps and spasm +had supervened upon the vomitings; but here they found two of the party on +board similarly affected. Here then is a very marked case without any known +predisposing local cause. Doubtless it was atmospheric, and in the hot +blast of pestilence which passed over them." + +Many more instances might be quoted, to shew that the germs of disease, as +well as of plants, are borne on the wings of the wind from place to place +{74} in one country, and from one country to another, the distance being no +obstacle, however great that may be.[28] "Dust and sands," says Sharon +Turner, "heavier than many seeds, are borne by the winds and clouds for +several hundred miles across the atmosphere, falling on the earth and seas +as they pass along." "The clouds not only bring us occasionally meteoric +stones, hail, and _epidemics_, but also vegetable seeds."[29] + +2nd. The transportation of seeds of plants by water requires very little +notice; every one is familiar with the mode in which coral islands, which +gradually rise out of the sea, become covered with vegetation. "If new +lands are formed, the organic forces are ever ready to cover the naked rock +with life.--Lichens form the first covering of the barren {75} rocks, where +afterwards lofty forest trees wave their airy summits. The successive +growth of mosses, grasses, herbaceous plants and shrubs or bushes, occupies +the intervening period of long but undetermined duration." + +The following may be cited as an instance of the transportation of disease +by water. "Cyprus lost almost all its inhabitants, and ships without crews +were often seen in the Mediterranean, or afterwards in the North Sea, +driving about, _and spreading the plague wherever they went on shore_."[30] + +It requires no argument to enforce the conviction that cottons, woollens, +furs, skins, &c. will retain the matter of infection for almost an +indefinite period; instances of the kind have been already given; it is +therefore easy to understand that portions of wrecks and ship's goods would +be a frequent though unsuspected source of infection. Dr. Halley mentions a +case, in which a bale of cotton was put on shore at Bermuda by stealth; it +lay above a month without prejudice, where it was hid, but when opened and +distributed among the inhabitants, it produced such a contagion that the +living scarce sufficed to bury the dead. Dr. Walker found seeds dropt +accidentally into the sea in the West Indies cast ashore on the Hebrides. +He says, "the sea and rivers waft more seed than sails." The waters of many +rivers induce diarrhoea and dysentery.[31] Well water also in many {76} +places has a similar effect, especially if any surface drainage happens to +find its way into the well. + +3rd. The part performed by man himself in the communication of disease to +his fellow creatures, is perhaps the most fruitful source of the extensive +spread of epidemic and contagious diseases. + +In the time of Moses, restrictions were laid on those who had the plague of +the leprosy to avoid contagion; the dictum for one so affected was, "he +shall dwell alone; without the camp shall his habitation be."[32] All the +ancient authors believed in the {77} infectious nature of pestilential +fevers, and some other diseases; but, according. to Mr. Adams, they held +that no specific virus was the cause, and merely a contamination of the +surrounding air by effluvia from the sick. Thucydides, Hippocrates, +Procopius, Galen, Plutarch, all recognized the property of communicability +from one individual to another of the plague; and Hecker, on the epidemics +of the middle ages, abounds with instances in support of contagion. As +regards small-pox and measles, Rhazes observes particularly the connection +that exists between the condition of the air and the severity or mildness +of these diseases, remarking that small-pox seldom happens to old men, +except in pestilential, putrid, and malignant constitutions of the air in +which this disease is usually prevalent. + +The history of the introduction of Scarlet Fever, Hooping Cough, Lues, and +other diseases into the various countries of the globe, is sufficiently +convincing that men carry about with them the seeds of disease; that while +these attach themselves to the persons and clothing of those who introduce +them into new climes, and flourish independently of cultivation, yet the +exotics which they foster with so much care, often disappoint their most +sanguine expectations; and these "languishing in our {78} hothouses can +give but a very faint idea of the majestic vegetation of the tropical +zone." Art in this procedure fails to accomplish here, what nature but too +sadly, under some circumstances, effects most readily. The germs of some +diseases though of an exotic character, under congenial influences of +various kinds, appear to flourish with native vigour: is it not so, also, +with some forms of vegetation? The aloe, a native of Mexico, which lives, +but does not thrive well, or reproduce under ordinary circumstances in this +country, will occasionally send forth a most luxuriant blossom;[33] so rare +is this, that some say it occurs every 50 or 100 years, but no law seems to +be established on this point, any more than the statement that we may +expect pestilential diseases at certain intervals. But that there are +intervals of _uncertain_ duration when the aloe will blossom, when the +grapes will ripen, and a general productiveness of exotics will occur, is +as certain as that seasons will occur when contagion will be rife, and a +most unusual multiplication of disease prevail. This is not an imaginary or +speculative notion,--all observers of seasons and diseases within the last +twenty years, may fully verify the statement. + +In 1846, a large vine, the black Hambro-grape, {79} ripened its fruit out +of doors, and was as fine as any green-house production; but during nine +years that the vine has been under my inspection, this was the only time I +have witnessed such a result. + +We are apt to attribute an abundant or scarce fruit season to temperature +alone, but this is an error--for we have before remarked, that though +certain lands may be in the same degree of latitude, the plants which +thrive well on one land, will not do so on the other: in fine, that where +reason and analogy would lead one to expect a particular form of +vegetation, a totally different Flora is presented to the view. These facts +are indeed suggestive of new and important deductions. Is it yet explained +why the town of Birmingham should be free from Cholera? There is a large +manufacturing population, a great number of poor, the usual overcrowding of +individuals in small chambers, a considerable amount of destitution and +depravity; irregular habits of living, and unwholesome diet, and doubtless +many parts of the town, which on investigation would have yielded all the +elements usually considered necessary for the localization of the disease: +but no--here was some repelling cause, some opposing agent to the +generation and propagation of the pestilential seeds. There are no known +laws by which inorganic matter could be supposed to observe such a +selection, or such an antagonism. Electricity, magnetism, ozone, gases, +exhibit no such elective properties that here they will destroy, and {80} +there they will spare; that they can almost depopulate small villages, and +scarcely find a victim in Birmingham and Bath. But if we suppose a living, +and multiplying matter as the cause of disease, many local causes may +conspire to arrest the development of the germs, or perhaps, even utterly +destroy them. + +4th. As to the time of latency, facts crowd upon us indefinitely, as +elements of comparison between vegetation generally, and disease in its +early stages and history. The seeds of plants are extraordinarily tenacious +of life. What a mysterious arrangement of the ultimate particles of matter +must there be, by which the vital force remains apparently inactive for +many years, and yet when the conditions arise favourable to its +manifestation, as it were by an extraordinary fiat, life appears. + +Previous to the year 1715, no broom grew in the King's Park, at Stirling; +but in that year a camp was formed there, and the surface of the ground +consequently was broken in many places. Wherever it was broken, broom +sprang up. The plant was subsequently destroyed; but in 1745 a similar +growth appeared after the ground had been again broken for a like purpose. +Some time afterwards the park was ploughed up, and the broom became +generally spread over it. "In several places in the neighbourhood of +Edinburgh," says Professor Graham, "the breaking of the surface produces an +abundant crop of Fumaria parviflora, {81} although the same plant had never +before been observed in the neighbourhood. It is impossible to say the +lapse of time since these were buried, before they were again excited to +the performance of all their vital functions." Dr. Graham also gives +another proof of the vital force existing in seeds. "To the westward of +Stirling there is a large peat bog, a great part of which has been flooded +away by raising water from the River Teith, and discharging it into the +Forth,--the under soil of clay being then cultivated. The clergyman of the +parish standing by while the workmen were forming a ditch in this clay, +which had been covered with fourteen feet of peat earth, saw some seeds in +the clay which was thrown out of the ditch; he took some of them up and +sowed them: they germinated and produced a crop of Chrysanthemum septum. +What a period of years must have elapsed while the seeds were getting their +covering of clay, and while this clay became buried under fourteen feet of +peat earth!"[34] + +{82} + +What limit can there be to the dispersion of seeds when their vital +properties may remain so long unimpaired? The seeds of which we have been +speaking were, no doubt many of them, washed away with the waters of the +Teith, and carried by the stream into the Forth; and who shall then mark +their destination; for we have seen that by such means the most distant +lands are supplied with vegetation; for whence come the plants which cover +the Coral Islands, unless by the air and the water, and that both +contribute, has been incontestably proved. Dr. Lindley states that melon +seeds have been known to grow when forty-one years old; maize thirty years, +rye forty years, the sensitive plant sixty years, kidney-beans a hundred +years. But seeds in general have an indefinite period, apparently, at which +they can retain their power of germination; for many of the seeds which had +been kept in the herbarium of Tournefort for more than a century, were +found to have preserved their fertility. + +It has now to be shewn that the germs of disease also retain their vital +powers in a state of dormancy during a lengthened period. + +{83} + +Mead has very judiciously observed, "to breed a distemper, and to give +force to it when bred, are two different things." He further remarks, that +the seeds of the Plague may confine themselves to a house or two during a +hard frosty winter, and be preserved, and again put forth their malignant +quality as soon as the warmth of the spring gives them force. It is +certainly very remarkable that the Plague of London, which commenced at the +latter end of the year 1664, should "lie asleep," as Mead says, from +Christmas to the middle of February, and then break out in the same parish. + +It has been also known that an infected bed laid by for seven years had +done infinite mischief on being again brought into use. Indeed, it is quite +uncertain for how long a period woollen, fur, linen, cotton, and other +articles may retain infectious matter in a dormant state. It has been +supposed by some that in closely packed bed and body clothes a +multiplication of the germs may and does take place, nor do I see any +reason why this should not be the case, for these articles contain within +their structure the effluvia of the animal body, and they may possibly +there find sufficient nutriment for their development. Nees von Esenbeck +believed that some of the minute Cryptogamia were re-produced in the air, +we are not therefore exceeding philosophical conjecture when we imagine a +basis and substratum, though an unusual one, for the germs of vegetation. +Exclusion from air and light, {84} however, as would be the case in +packed-up clothes, would _a priori_ give a better colour to the conjecture, +as these are the usual conditions necessary for the growth of seeds. + +Small Pox and Cow Pox matter, which are now proved to be the same virus, +the former modified by having been through a process of growth and +maturation in the cow, are both remarkable for exhibiting their active +properties after having lain dormant for a considerable time. And each, +though so closely allied, retaining its specific properties. + +This peculiarity in the history of Small Pox virus suggests a comparison +with some phenomena of vegetation, _viz._ that of grafting or budding. The +lower Cryptogamia in their fructifications resemble rather multiplication +by buds than by seeds. M. Moyen's idea is that every spore or little +globule, independently of its neighbouring one, lives, absorbs, +assimilates, grows, and re-produces on its own account; this is certainly +the characteristic of the Torula and the Uredo, and doubtless is so of many +other of the Cryptogamia, the Protococcus nivalis is another instance. +Other modes of cultivation produce also great varieties of results of an +unexpected kind. + +Would any one, says Dr. Walker, imagine that cabbage, cauliflower, savoy, +kale, brocoli, and turnip-rooted cabbage, were the same species? yet +nothing is more certain than that they are only varieties produced by the +cultivation of the Brassica oleracea, {85} a plant which grows wild on the +sea-shores of Europe. + +These varieties in vegetables have now become permanent, and though it is +supposed that each is liable to return to its original condition, I am not +yet certain that such is the tendency. A deterioration is not unlikely to +ensue in the course of time, because the propagation by seeds must +necessarily very much approach the system of intermarriage, on which Mr. +Walker has so ably written and clearly shewn that as a result we may +invariably expect a deterioration of the species. Dr. Darwin has also +poetically described what his experience taught him. + + "So grafted trees with shadowy summits rise, + Spread their fair blossoms and perfume the skies, + _Till canker taints the vegetable blood_, + Mines round the bark and feeds upon the wood; + So years successive from perennial roots, + The wire or bulb with lessened vigour shoots, + Till curled leaves or barren flowers betray + A waning lineage verging to decay; + Or till amended by connubial powers, + Rise seedling progenies from sexual flowers." + +The minute nature of the germs of disease preclude all possibility of their +being submitted, as far as we know at present, to the inspection of the +physiologist, but we may infer many facts from results. In the same way, +though with humbler {86} ideas, as Cuvier could build up an animal from a +single bone, can we by a combination of facts infer the existence of living +beings and conjecture their forms. "The re-production or generation of +living organized bodies is the great criterion or characteristic which +distinguishes animation from mechanism." We find the virus of Small Pox, +according to Mr. Ceely's experiments, developing itself as a constitutional +disease upon the cow, and becoming modified into a form known as the Cow +Pox; this resembles the process of cultivation by which a species is +converted into a variety, this variety remains for a certain time +persistent; the time is not yet known, but it is known that by degrees, as +stated above, a deterioration occurs, and fertility becomes impaired, "a +waning lineage verging to decay," and this has been observed as a feature +in the result of vaccination. I believe Dr. Gregory was one of the first to +notice this fact, and deemed it necessary to obtain fresh lymph from the +cow; this has been done, and it is not improbable, if the analogy we have +drawn be correct, that the slowly spreading scepticism regarding +vaccination may be arrested in its progress. If we can explain the +deterioration of cow pox virus on this principle we have a hold at once +upon the public, and can assure them that the efficacy of the proceeding is +as certain as in the time of Jenner. The people, I contend, have a right to +demand of us the reason why vaccination is not so efficacious as formerly, +and I {87} affirm as unhesitatingly that we are bound to give the subject +our most earnest attention.[35] + +Now concerning the re-production of Cow Pox matter, and assuming it to +resemble that of the lower Cryptogamia, we can easily understand how +degeneration in a course of years should ensue, for we find that though the +Small Pox is a constitutional disease, that produced by vaccine lymph is a +local affection, so that it bears the relation that grafting does to +vegetation, and it is not improbable that such a modification takes place +in the germs by passing through or becoming generated in the blood of the +cow, that they entirely lose their original and characteristic form of +reproduction: the seeds of the disease were originally capable of +vegetating, if I may be allowed to use the term, by diffusion through the +atmosphere; they now, however, have lost that property, and require to be +grafted to exhibit any manifestation of vitality. + +How often will the seeds of a cultivated fruit grow? If you bud it upon +another plant, you obtain a being exactly like the parent, but this, as we +have seen, deteriorates in a course of years, we have also seen that the +virus deteriorates; but not to stretch this point to an unseemly length, I +cannot avoid expressing my conviction, that these are elements of +comparison, possessing an interest and a practical utility of no small +value. + +{88} + +I have before said, that the reproduction in the Cryptogamia, rather +resembles budding than seeding. If we observe the Torula, or take the +process of all formation, generally it will be found to accord more exactly +with the budding than the seeding process, and this peculiarity is not +confined to vegetation, it is also a marked feature in the reproduction of +infusoria, sponges, polypes, &c. + + "New buds surround the microscopic plant." + +The reproduction of plants and animals appears to be of two kinds, solitary +and sexual; the former occurs in the formation of the buds of trees, and +the bulbs of tulips. + +The microscopic productions of spontaneous vitality propagate by solitary +generation only. + +We have but reached the threshold of this vast and interesting subject, the +experiments which suggest themselves to the mind while reflecting upon it, +would alone occupy a whole life of leisure, and I can but feel how forcibly +Mr. Sewell's words apply to us: "The grand field of investigation lies +immediately before us, we are trampling every hour upon things which to the +ignorant seem nothing but dirt, but to the curious are precious as gold." + +It is difficult, perhaps, to bring many instances, in which the germs of +disease have lain dormant for a lengthened period, because many may take +exception to them, from the fact, that sporadic cases of {89} most epidemic +and infectious diseases, are rarely absent from any country in which those +diseases have become indigenous, and these cases may be said to be the foci +whence originates the epidemic constitution of the air; this, however, +would not invalidate the supposition, because one of two inferences must be +drawn, either that the germs of disease always exist in a dormant state, +requiring circumstances and conditions only for their development, or that +the germs are imported from some distant locality, where the disease has +occurred, and finding a nidus there, grow and multiply.[36] Whichever +notion we take, however, matters very little to the fact of the dormancy of +the germs, for in both, a certain period elapses between their transmission +and their propagation. It may fairly be presumed, that sometimes one method +may apply {90} and sometimes the other, perhaps both during general +epidemic conditions of the atmosphere. + +The Oidium vitis attacked the vines partially last year, and I believe +generally spared other forms of vegetation; but this year in my vicinity, +cucumbers, melons, and vegetable marrows, are all suffering more or less +under the disease.[37] How shall we say, whether are the seeds of last year +the cause of the general diffusion at the present time, or were there a +sufficient number of old and dormant seeds, universally diffused, and only +waiting opportunities for multiplying themselves? We are here on the horns +of a dilemma; and spontaneous generation, from which one naturally shrinks, +can alone extricate us, if we do not admit diffusion and dormancy. I think +I may, without undue assumption, affirm that a period of latency of +indefinite duration, applies as cogently to the germs of disease as to +those of plants. + +There is yet one other point in connection with this subject, and that is +the apparent extinction of some diseases, at any rate their non-appearance +in certain localities, which had been at one time congenial to them, and in +which they flourished. We have seen, in illustrating the dormancy of seeds, +that the broom must have been a common plant at {91} some considerable +period back, in the King's Park at Stirling, or on that site. + +Then again, the appearance of Fumaria parviflora in the vicinity of +Edinburgh, in several places where the ground is broken, is sufficiently +convincing that this plant must once have been a common form of vegetation +there; and as it had never before been observed in the neighbourhood, there +must have been a combination of peculiar circumstances capable of rendering +germination impossible, otherwise a continued multiplication, as in other +forms of vegetation, would have followed of necessity. + +But besides these instances, how many are passing under our own eyes of the +disappearance of plants under the influence of cultivation, and the +generation of the noxious fumes arising from different and innumerable +manufactories. In the vicinity of large cities and manufacturing towns, how +rarely do we see healthy vegetation; shrubs and animals drag on a sickly +and almost unprolific existence, and their term of natural life is much +shortened. + +And if we compare diseases with this peculiar feature of vegetation, how +very close do we find the analogies. The Sweating Sickness which appeared +in the latter part of the fifteenth century, and at certain intervals +multiplied and extended itself at first only in this country, but +ultimately more or less over the continent of Europe, has {92} never since +the year 1551 shewn any symptom of productiveness, indeed for all we know +the disease may be extinct; on the other hand, it is impossible to say +whether or not circumstances may arise, under which it may commence again, +to put forth its energies and again desolate the land.[38] + +Since 1665, the Bubo-plague has not found a congenial soil in this country, +or if the seeds be here, which is more than probable, the necessary +conditions to excite them to activity do not exist. + +It cannot be imagined that with all the merchandize which comes into this +country from the Mediterranean, but that an abundance of the germs of the +disease are annually brought into our ports, and disseminated throughout +the land. The law by which we have seen that they possess a power of +vitality and reproduction, holds now as it did in former times;--the +properties of matter never alter, but the conditions under which they exist +may be so modified, as to influence their properties, and the usual course +of their operations. It is therefore to {93} an alteration or modification +of conditions that we are to look for the exemption, during the last two +centuries, from an invasion of the Plague. To say what those conditions may +be in their totality is difficult, perhaps impossible. We may generalize on +the subject, and imagine the reason discovered, but all those causes which +were said to have conspired to favour the spread and contamination with +Plague, were as distinctly specified and attributed, as the cause of our +late infliction with Epidemic Cholera. Why then did we have the Cholera and +not the Plague? To what particular element was it--in the mode of living, +of destitution, of filth and want of drainage--can it be ascribed that we +suffer under one disease, and not under the other? + +We have made some few observations and comparisons on the mode of +dispersion of plants and diseases,--but there is yet one more point which +invites notice. Not only do seasons vary in their effects on vegetation in +a remarkable and unexplained manner, but there are many localities to which +some special form of vegetation attaches, and which appear to have a power +of exclusion of other forms; and as yet I have not been able to trace the +connexion, nor can I discover it in the writings of botanists and +travellers, who would be most likely to have sought an explanation of so +interesting and curious a fact. Dr. Prichard has on this subject some very +apposite illustrations. "Still further southward, the austral temperated +zone completely {94} changes the physiognomy of vegetation, and the Isle of +Norfolk has, in common with New Holland, the Auracania found also in the +harbour of Balade, and with New Zealand, the Phormium tenax. It is however +remarkable, that this vast island, composed of two lands, separated by a +channel, though so near New Holland, and lying under the same latitude, +differs from it so completely, that they display no resemblance in their +vegetation. Yet New Zealand, so rich in genera peculiar to its soil, and +little known, has some Indian plants: such as Pepper, the Olea, and a +reniform Fern, which is said to exist in the Isle of Maurice." + +I must quote one more passage from Dr. Prichard's excellent work. "We have +one instance of an island at no great distance from a continent, having a +peculiar vegetation. Mr. R. Brown has remarked, that there is not even a +single indigenous species characterising the vegetation of St. Helena, that +has been found either on the banks of the Congo, or on any other part of +the Western coast of Africa. Does the diversity of marine and atmospheric +currents more completely separate this island from the continent, than its +situation would imply; or are the nature of soil and other local +circumstances, the cause of so marked a diversity? The last supposition +seems the most probable; because not only the species of plants, but +likewise the genera in St. Helena, are different from those of the African +coast." {95} + +We are not without instances of diseases, observing this peculiarity which +attaches to plants; but their specific characters have hardly been +sufficiently considered in reference to climate and situation, together +with diet and local influences, to afford us accurate data for comparison. +It has, however, been remarked, in every country where Epidemics have +prevailed, that some districts or tracts of country, though supposed to +possess all the qualities favourable to the development of the diseases, +have nevertheless been entirely or nearly free from them. The following +passage on the course of the Cholera gives an example of this peculiarity. +"Whenever the malady deviated, so to speak, from its normal direction, and +passed towards the west, it seemed incapable of propagating itself; and +_died away spontaneously, even in places which appeared to be well fitted +for its reception_.--The rich fertile and densely peopled countries to the +right of the Dneiper, enjoyed an equal freedom from attack, which can only +be explained by the fact that they were situated _beyond the line of the +disease_." With this I close the subject of the diffusion of plants and +diseases, though it would require a volume of itself, to record all that +has been noticed. I have endeavoured to select such instances as shall mark +distinctly the features which point to comparison without overloading the +enquiry. + + * * * * * + +{96} + +SECTION IV. + +THE RELATION BETWEEN EPIDEMIC AND ENDEMIC DISEASES. + +Epidemic diseases, which multiply their germs in any climate, and under +apparently the most varying conditions of temperature and hygrometric and +electrical states of atmosphere, offer many points of contrast with Endemic +affections, and many of relationship. The latter are traceable to a certain +extent, to geological and geographical positions of the localities where +they are observed to prevail, in combination with atmospheric vicissitudes +and peculiarities, as well as to extent of cultivation of the soil: it has +been remarked that the sickly island (as it is called) of St. Lucia has +certain salubrious parts, but these are where sulphur abounds; this +geological peculiarity has been deemed sufficient to account for the +absence of endemic affections in these parts, and with much force of +reason; for in the neighbourhoods where sulphur or sulphurous acid, a +compound of sulphur, is an element prevalent in the soil or atmosphere, +vegetation and the ague disappear together. + +Now ague, and other endemic fevers, doubtless originate from some allied, +if not identical cause; for the localities in which they appear have so +many {97} features in common, that we are constrained to acknowledge that +endemic fevers have some relations and analogies, though not yet +unravelled. + +Geographical situation, together with certain vegetation, particularly of +grounds which grow rice, is one remarkable for the production of endemic +affections. But the soil which generates or gives force to the +contaminating matter, is not alone the part where human beings feel its +influence most severely. A low marshy ground, prolific of malaria, may be +comparatively free; while some neighbouring elevated land, to which +prevailing currents of air waft the volatile elements of disease, may be +desolated by their virulent and concentrated action. "Malaria may be +conveyed a considerable distance from its source, _and be condensed_ in the +exhaled vapour, when attracted by hills or acclivities in the vicinity, and +when there are no high trees or woods to confine it, or to intercept it in +its passage." + +The inhabitants of the city of Abydos were at one time subject to disease, +arising from malaria, generated in some neighbouring marshes; by draining +these marshes, which suspended the growth of rank vegetation, the city +became healthy. + +Rome is in like manner even now subject to fevers, having a similar origin. +Sir James Clark says, "Among the more prevalent diseases of Rome, malaria +fevers are the most remarkable, and claim our first notice." He considers +the fevers to be of exactly the same nature as those of Lincolnshire {98} +and Essex in this country, of Holland, and certain districts over the +greater part of the globe. To the climate, the season, or the concentration +of the cause of these fevers, he attributes their varieties. It is the same +disease, he says, whether from the swamps of Walcheren, or the pestilential +shores of Africa. + +From July to October the inhabitants of Rome are most subject to these +affections. + +Sir James Clark further says: "It may be stated as a general rule, that +houses in confined shaded situations, with damp courts or gardens, or +standing water close to them, are unhealthy in every climate and season; +but especially in a country subject to intermittent fevers, and during +summer and autumn. The exemption of the central parts of a large town from +these fevers, is explained by the dryness of the atmosphere, and by the +comparative equality of temperature which prevails there." + +In this respect there is a marked difference between an epidemic and an +endemic affection; for when an epidemic disease attacks a city or town we +do not discover that the central parts are more exempt than others; indeed, +it is rather the contrary; for the most crowded parts of towns and cities +are those, if not exactly in the centre, which would be comprised in a +space nearer to the centre than the circumference; and it has been in those +parts generally where the epidemic influences seem to have exercised the +most potent sway. One would more naturally suppose, that a city surrounded +by {99} paludal miasm, and not itself being capable of generating the +poison, should be more affected at the circumference, from the simple fact +that the paludal germs, which rise in the air, are suspended in the fogs +and dews of the atmosphere. These, unless widely dispersed by the winds, +would remain within a comparatively confined space; and those situations +nearest to them would be most subject to their influence. Besides, it has +been shewn, that a small wood or hill, or even a wall, has been sufficient +to cut off or obstruct the paludal miasm. + +Without enumerating all the known endemic diseases, two or three may be +alluded to for our present purpose; viz. that of shewing that endemic and +epidemic diseases have a similar origin.[39] + +It is well known that under certain favouring conditions an endemic may +become a malignant and pestilential disease; that Yellow Fever, which is +always endemic in the west, Cholera in the east, and the Plague in the +south of Europe and north of Africa, every few years takes on an epidemic +form, and desolates considerable tracts of country.[39] + +The Pestilence which raged in the summer and autumn of 1804 in Spain, +commenced at Malaga, and remained for a considerable time confined to its +{100} boundaries, in consequence of the measures of precaution that were +used, in preventing all communication between the inhabitants of the +infected city and those living in the surrounding country. It was only in +consequence of persons escaping through the cordon, and passing into the +interior of the country, that the disease spread, and extended its ravages +to distant places. + +It appears to be quite clear, that this disease may properly be considered +in the first instance of endemic origin; but the tendencies, atmospheric +and otherwise, were such as to favour its multiplication in other districts +than that in which it first came into active existence. From this we may +infer, that the seeds of the disease were dormant, and only became roused +into vital activity by fortuitous circumstances. Dr. Rush states, that the +endemic disorders of Pennsylvania were converted, by clearing the soil, to +bilious and malignant remittents, and to destructive epidemics. Dr. Copland +says, it has been observed, especially in warm climates, and in hot seasons +in temperate countries, that when the air has been long undisturbed by high +winds and thunder-storms, and at the same time hot and moist, endemic +diseases have assumed a very severe and even epidemic character. + +Dr. Robertson also confirms this view. "Endemic diseases, in cases of +neglect and preposterous management, are found to become more malignant +even in the most temperate climates; and to {101} generate a matter in +their course, capable of producing a particular disease in any +circumstances. _Indeed the origin of every_ contagious fever unattended +with eruptions, with the exception of Plague, must commence in this way." +Why Dr. Robertson should except eruptive Fevers and Plague I cannot +understand, for they must have had a commencement; and their many points of +similarity indicate, if not an identical, an analogous source to other +endemic fevers. + +It will doubtless be generally acknowledged that endemic and epidemic +diseases depend upon some unknown agents, having their source in malarious +districts, and being capable of assuming either a contagious or +non-contagious character, according to circumstances. + +If, therefore, we find that under any conditions an endemic affection +becomes capable of being propagated by contagion, the same law will hold +with regard to it as to the Plague; that the power of reproduction in this +matter is evidence of life, according to the doctrine laid down in the +earlier part of this work. But whether or not infection be admitted, a +matter generated in a malarious district, if confined in its effects to +that district alone, would not necessarily imply an inorganic nature of the +poison; for it is difficult to understand how inorganic poison, prevailing +generally over a certain tract of country, could select particular +individuals for its victims. If chloroform, chlorine, carbonic acid, +sulphuretted hydrogen, or even spores of poisonous fungi, (as {102} +supposed by Mitchell, which, as he regards their effects, would act in a +similar manner to inorganic compounds) were the agents, all persons would +suffer more or less, and the majority be similarly affected. We do not find +that uniformity of symptoms, which attend upon the exhibition of poisons in +the ordinary acceptation of the term, poisoning. This subject shall be more +particularly considered, when treating of the influence of organic germs on +animals and plants. + +The history of the Eclair steamer is particularly interesting, as shewing +the extraordinary tenacity with which the germs of disease attach +themselves to vessels, which we may call floating houses. + +The crew of the Eclair contracted Yellow Fever on the coast of Africa, and +a number of them died. The remainder, sick and well, landed at Bona Vista, +one of the Cape de Verde Islands, and the vessel underwent a process of +washing, whitewashing, and fumigating. Nevertheless, on the return of the +ship's company, the disease broke out again with equal intensity, and the +vessel was ordered home. Sixty-five out of 146 officers and men, who +composed the crew, died of the disease before reaching Portsmouth, and +twenty-three were sick at the time of arrival. + +Eight days after the Eclair left Bona Vista, a Portuguese soldier who had +mixed with her crew died in the fort which had been occupied by them. Other +soldiers then fell sick, and the fort was abandoned. The fever still +spread. + +From the 20th September, when the first soldier {103} was attacked, to the +first week in December, the fever continued to rage, and at that period it +had found its way into almost all the country villages. The fever was +believed to be the genuine black vomit fever; it proved contagious almost +without exception to the nurses of the sick. + +This is an abstract of Mr. Rendell's letter to Lord Aberdeen, Mr. Rendell +being British Consul at Bona Vista. + +Now at the time the fever broke out in the island the weather was +extraordinarily hot, and much rain had fallen, and the town itself was +badly drained and in a filthy state; can it be imagined then that the seeds +of a disease liable to assume a pestilential character should lie dormant +or be annihilated under circumstances the most favourable for their +development, especially when we know that endemic diseases may assume a +malignant character? + +This is just one of many cases which confirm our opinion in this respect, +that plants and diseases are not long in making their appearance where the +soil and atmosphere are congenial. + +The tenacity with which the disease attached itself to the Eclair is +sufficiently explained in the absence of due ventilation; in fact, that in +the first instance there was no ventilation at all in the hold of the ship. +This also the more readily affords a clue to the disaster through all its +stages, first in the contraction of the disease as an endemical affection +in the vessel; secondly, in the multiplication of the {104} germs in the +damp ill-ventilated hold, in a warm climate; and thirdly, the persistence +and entire localization of the disease to the vessel when it arrived in the +climate of the British shores; while, fourth and lastly, in the unusually +hot and damp island of Bona Vista, the seeds of the disease were sown, and, +as we might expect, multiplied indefinitely. + +The consecutive attacks of the crew of the Eclair shew that here a noxious +gas or a vaporized inorganic poison could not have been the cause of the +disease, for as I have before said, in this case the attacks should have +been simultaneous; we find, on the contrary, that as the depressing effects +of the melancholy condition of the crew was almost hourly undermining the +health of the stoutest of them they as surely became the victims. The +Kroomen, or natives on board the ship had not suffered, shewing that they +were inured to the miasm, or were destitute of that condition of blood +which would be favourable to a propagation of the materies of the disease. + +The Eclair we learn had left Bona Vista eight days when the first victim +breathed his last; this would give perhaps three or four days for the +incubation of the disease in the patient, or supposing he had not +contracted the germs of the disease before the crew of the Eclair left the +fort, some local favouring conditions were the means of keeping the germs +in a fertilizing state, for it is clear from this spot the infection spread +as from a centre or focus. {105} Such instances as these might be +multiplied to extend the length of the enquiry, but, I think, to little +advantage. The chief facts to be gathered are that an endemic affection +became epidemic and pestilential, contrary to its usual mode, for the +Portuguese official physician, on being consulted by the Governor of the +Island as to the safety of landing the contaminated crew, said, "No danger +at all; I have often brought sick men on shore coming in vessels from the +African coast, and I never knew any ill effects to arise." Putting the most +reasonable construction on this emphatic and straightforward language, we +may presume that ordinary, remittent, and yellow fever had been commonly +imported into the island, for it is not to be supposed but that both forms +of disease must have existed among those sick men who had "_often been +landed_," under the sanction of the Portuguese physician. + +To take another instance; intermittent fever or ague, is a disease known +among almost all nations of the world, but it usually occurs in the endemic +form only. It is universally supposed to depend entirely upon marsh +effluvia, and we are accustomed to consider it as attaching only to low +lying countries;[40] but this is not always the case, for disease in {106} +this respect, like vegetation, may be found in various latitudes, to +accommodate itself at varying altitudes, to the temperature and climatic +relations, so as to appear indigenous. But though our prejudices are in +favour of a simple miasmatic source of ague, as its sole cause, there are +some who believe in its infectious nature. M. Sigaud, in his work on the +Climate and Diseases of Brazil, speaks of Epidemics of _grave intermittent +Fever_, and Dr. Copland says, that the epidemic prevalence of ague is a +better established fact than its infection, and has been admitted by most +writers.[41] We have, therefore, but to go one step further to arrive at +infection, after having found that an endemic disease under peculiar +circumstances, though but rarely, becomes {107} epidemic. The number of +persons attacked by ague in a malarious district, in proportion to the +population, is not so great as might be expected, considering that they are +always subject by night and day, more or less, to respire the air +containing the germs of intermittent fever; we might, therefore, deny the +paludal source of the affection, as reasonably as deny infection, if we +found that occasionally, persons, though subject to all the usual +influences, yet escaped all injurious consequences. + +There are grades and varieties of infectious diseases, from the most +inveterate to the most mild and doubtful; but that all, without exception, +which can in any way be traced to a specific generating and organic cause, +may assume an exalted infectious character, and that the most inveterate, +on the contrary, may more resemble the mild and doubtfully infectious +forms, is a conviction that must be forced on all who pursue this enquiry +with unbiassed interest. + + * * * * * + + +{108} + +CHAPTER III. + +THE REASONABLENESS OF THE APPLICATION OF THE FACTS TO THE INFERENCE. + +-------- + +SECTION I. + +THE CHEMICAL THEORY OF EPIDEMICS UNTENABLE. + +It has been inferred that the germs of disease possess the property of +vitality, and a number of facts have been adduced to support the +proposition that vitality is the indwelling force by which the matter +generating epidemic and endemic disease exercises its influence over man +and animals. The reasonableness of the application of these facts to the +end in view has now to be considered. Chemistry cannot account for +epidemics. + +Our first subject of reflection points to the chemical discoveries of the +last few years, and particularly to those of the great German chemist +Liebig. We find in the first paragraph of his Organic Chemistry applied to +Physiology and Pathology, the following words: "In the animal ovum, as well +as in the seed of the plant, we recognize a certain remarkable force, _the +source of growth_ or increase in the mass, _and of reproduction_ or of +supply of the matter consumed; a force in a state of rest. By the action of +external influences, by impregnation, by the presence of air and moisture, +the condition {109} of static equilibrium is disturbed. This force is +called the _vital force_, _vis vitae_, or vitality." + +The doctrine of Liebig, that the vital force manifests itself in two +conditions, or rather, that it is known to be in two different states, that +of static equilibrium as in the seed, and in a dynamic state, as in that of +growth and reproduction, is perfectly applicable to the germs of disease; +the static equilibrium is referrible to the matter of vaccine lymph when +dried and preserved for use, and the dynamic forces of the matter are known +to be in operation during its reproduction and growth in the system of the +vaccinated child. + +Then as to reproduction of matter by any chemical process, our author can +furnish us with no examples, for even in his explanation of the causes of +disease he is quite silent on this point, merely acknowledging that +diseased products must be either rendered "harmless, destroyed, or expelled +from the body." He further says, that "in all diseases where the formation +of contagious matter and of exanthemata is accompanied by fever, two +diseased conditions simultaneously exist, and two processes are +simultaneously completed," and that it is by means of the blood as a +carrier of oxygen that neutralization or equilibrium is established. Liebig +thus admits that an agent exists in the blood, capable of deteriorating it +at the expense of the oxygen, which he maintains is contained in the red +globules; he further acknowledges that two processes of diseased {110} +action are going on at the same time, and though he does not explain them, +I imagine him to mean that new contagious matter is generated and +eliminated from the blood, and that at the same time, there is that +condition of body which he would call simply a diseased state, and +characterizes it thus: "Disease occurs when the sum of vital force which +tends to neutralize all causes of disturbance, (in other words, when the +resistance offered by the vital force) is weaker than the acting cause of +the disturbance." + +If I rightly apprehend his notions, they perfectly harmonize with my ideas, +to a certain extent, on the subject. They accord, at any rate, most +completely with the theory attempted to be established, and fully confirm +the reasonableness of the application of the facts recorded to the +inference drawn from other sources. The difference only rests on the +question whether vitalized or non-vitalized matter is the _fons et origo +mali_. + +How is the production of new matter, resembling that originally causing the +disease, to be explained by any known hypothesis, except on the assumption +of living organized matter? Though Liebig and Mulder both deny the fact, +that the Torula cerevisiae is the sole agent in the process of +fermentation: they both equally fail in shewing upon what it does depend, +and their difficulty rests entirely on their incapacity to explain the +uniform reproductive properties of the matter engaged in this, as well as +in all other allied operations. Liebig's statement {111} however on this +matter requires notice--he says, "that _putrifying_ blood, white of egg, +flesh and cheese, produce the same effects in a solution of sugar, as yeast +or ferment. The explanation is simply this; that ferment or yeast is +nothing but vegetable fibrine, albumen or caseine, in a state of +decomposition." + +This state of decomposition, however, involves a much more complex +proceeding, than simply a reduction of matter into its elementary forms of +gases, earths, and minerals; for we nowhere find decomposition of this kind +going on without the development of some organized bodies, either animal or +vegetable: and since we have seen that the spores of the cryptogami are +always in existence in the atmosphere, and making their appearance under +favouring conditions, and especially when we find that fermentation is +invariably accompanied, and I may safely say, preceded by the deposition in +the fluid of the sporules of the Torula, we can hardly believe that they +are any other than the sole agents of the process. I have now a +considerable quantity of the Torula obtained from the urine of a diabetic +patient, in which they appeared, as it were, spontaneously. After the urine +had been allowed access to the air for a certain time, and the whole of the +saccharine matter was converted into new compounds, reproduction of the +Torula ceased;--and those which remained when the process was completed, +still continue as organic cells, deposited {112} in the bottle in an inert +state, but ready, on the addition of fresh sugar, as has been proved, to +resume an active existence. These germs, it is now well known, may be dried +into powder, so as to be blown away like dust without any, or but little, +detriment to their vital energies; and there is now no doubt that they +exist in this condition in the air, as do the spores of mucor, aspergillus, +oidium, agaricus, and all other fungi. + +Mulder, however, does allow some properties to the yeast vesicle; he says, +"a variety of strange ideas have been entertained respecting the nature of +yeast; recent experiments have convinced me that it undoubtedly is a +cellular plant consisting of isolated cells. They resemble the composition +of cellulose in some respects, but differ from it in many." "These +vesicles, consisting of a substance resembling that of cells, do not +contribute in the least to the fermentation, but are exosmotically +penetrated during fermentation by the protein compound." These chemists +seem to have an instinctive horror of allowing any active properties to the +yeast vesicle, that is as far as the conversion of sugar into carbonic acid +and alcohol is concerned in the act of fermentation. Dr. Carpenter, as if +desiring to conciliate the chemical and physiological disputants, considers +that the truth is to be found in the mean of the two extremes,--that is, +that the process of fermentation is neither entirely dependent on chemical +laws, nor on those laws which preside {113} over the growth of reproductive +matter, but is a process in which both perform certain offices, each +depending on the other to produce the combined result; he thus approaches +more nearly to the theory of Mulder, than that of Liebig. + +But to revert to Mulder, he speaks of the Torula cells being "exosmotically +penetrated during the process of fermentation by the protein compound." Now +the Torula is acknowledged to be one of the Fungals, and the chemical +constituents of the Fungi approach very nearly that of animal tissues. They +contain a peculiar principle, residing in and obtainable from them, termed +Fungin, which is as highly azotised as animal fibre. The protein compound +alluded to, Mulder says, is not gluten, because insoluble in boiling +alcohol, and not albumen, because it is very readily dissolved in acetic +acid, and he regards it as a superoxide of protein. This superoxide of +protein can only have been produced by a vital action in the cells of the +Torula, and as the fungi consume oxygen, and give out carbonic acid, we +clearly have all the elementary conditions for their growth in almost all +decomposing animal and vegetable matters. It is the nature of the fungi to +live on organized matter, but always when it has a tendency to decay; it is +for this reason they have been called "Scavengers." Again, we can +understand why some animalized or nitrogenous matter should be necessary +for fermentation, otherwise fungi could not grow, nitrogen being an +essential constituent of {114} their structure, and further fermentation +does not commence without the presence of oxygen, and like as in animals, +this gas supports their existence. The conversion of sugar into alcohol is +represented by the following formula:-- + + RESULT. + Sugar. Alcohol. Carbonic Acid. + Hydrogen 3 3 + Oxygen 3 1 2 + Carbon 3 2 1 + +If therefore the process were merely of a chemical nature, where is the +necessity for atmospheric oxygen to accomplish the end? it is quite certain +that fermentation cannot go on without its presence. Let us compare the +action of ferment or yeast in a dried state to the action of albumen, which +Liebig says is sufficient when decomposing to set up fermentation. "The +white of eggs when added to saccharine liquors requires a period of three +weeks, with a temperature of 96deg F. before it will excite +fermentation."[42] But any saccharine liquor on exposure to the air, though +entirely destitute of albumen or gluten, will ferment, and the Torula may +be found in it. I have found the Torula in a great variety of syrups which +have spontaneously undergone fermentation. I have also discovered that the +development of the cells is delayed or accelerated by the nature of the +ingredient used in flavouring {115} the syrups, with other peculiarities +which need not here be mentioned. + +But the conversion of starch into sugar by means of gluten requires some +notice, as by some persons it is associated in their minds with the organic +process of fermentation.[43] Mulder ascribes the latter in the first +instance to the action of heat, evidently believing that the +pseudo-catalytic operation of gluten upon starch is the type of all such +actions, and regarding them all as simply chemical, but we here distinguish +a wide difference; in the latter instance the gluten is decomposed, and +rendered unfit for a repetition of the chemical phenomenon, and if it is +desired to renew the action fresh gluten must be obtained, and a certain +temperature kept up, otherwise the experiment fails. How different is +fermentation: in the ordinary temperature of the atmosphere the yeast +vesicle will multiply, no incremental or unnatural addition of heat is +requisite, and it is one of the commonest and most natural instances of +vegeto-chemistry: the grape cannot shed its juice, nor the sugar cane its +sap without admitting these germs, which, under certain {116} conditions +multiply themselves and convert the saccharine elements into new compounds. +The method by which the conversion of starch into sugar is accomplished is +thus described by Dr. Ure. He says that if starch one part be boiled with +twelve parts of water and left to itself, water merely being stirred in it +as it evaporates, at the end of a month or two in summer weather it is +changed into sugar and gum, bearing certain proportions to the amount of +starch used. But "if we boil two parts of potato starch into a paste, with +twenty parts of water, mix this paste with one part of the gluten of wheat +flour, and set the mixture for eight hours in a temperature of from 122deg +to 167deg F. the mixture soon loses its pasty character, and becomes by +degrees limpid, transparent, and sweet, passing at the same time first into +gum and then into sugar."--"The residue has lost the faculty of acting upon +fresh portions of starch." + +Four points of contrast present themselves for notice as elements of +comparison with true fermentation. 1st. The starch solution has to be +boiled, so that heat, by which it is to be supposed that the starch globule +is ruptured, seems to be an essential portion of the chemical change, and +even this may in fact alone be sufficient in such a case to produce some +elementary change in the starch, and may prepare it for the subsequent +catalytic action of some related organic, though not vital material.[44] +{117} 2nd. Not only a summer heat is necessary, but a period of one or two +months time must elapse before the starch with the water simply becomes +converted into sugar, and if artificial heat is to be used to hasten the +operation, a temperature from 122deg to 167deg F. must be resorted to in +order to obtain the desired result. 3rd. When even this is accomplished +there is no reproduction of the fermenting matter, and artificial and +chemical means must again be applied to repeat the experiment. 4th. The +conversion of starch into sugar can be accomplished without the presence of +gluten at all, by the aid only of temperature and time. It seems to me, +therefore, to be entirely unnecessary to occupy more space in the +elaboration of a proof of the doctrine that the germs of the Torula are the +sole agents in the conversion of saccharine fluids into alcohol and +carbonic acid. By another chemical process starch can be converted into +sugar, but I am not aware that hitherto any method has been discovered by +which sugar can be converted into alcohol except by the process of +fermentation proper. + +I have been thus particular in commenting on this subject, as it bears, in +an especial manner, on the question under consideration. + +{118} + +The physiologist cannot afford to lose this process from the category of +chemico-vital, or biochemical manifestations.[45] The philosophy of the age +has a tendency to make every thing chemical; it is true that the Divinity +is as much seen in the laws which govern the elementary particles of +matter, as in those laws which preside over the transmutation and +sustentation of those elementary and inorganic particles, when compounded +in the tissues which are engaged in the formation of living beings. The +laws by which acids and alkalies neutralize each other, and the affinities +single, double and elective, which the particles of matter exhibit, +together with the influences of light, heat, and electricity upon almost +every condition of matter, are as truly wonderful as the creative power. +Man may, in many instances, imitate the processes of nature, he can render +iron magnetic, and form alkaloids, but the {119} laws which govern the +particles of matter are still the secret of the whole proceedings. We do +but interpret the language of nature in discovery, the book is ever open +before us, and every atom of the world is a word and a theme, capable of +occupying the short span of sublunary existence allotted to man. We have +read of "sermons in stones," but a book has been written on a "pebble."[46] + +To return, as we every where in nature find a gradual transition in the +forms, arrangements and properties of matter, so we may expect to find a +link between the inorganic and vital chemistry of nature. The fungi, by +which we contend this transition appears to be accomplished, are also a +link in chemical composition, between the animal and vegetable kingdom, and +not only in that, but in their subsisting upon matter which has been +organized, they are deoxidizers and reducers, as the vegetable kingdom in +its highest function is a compounder. To their functions and offices in the +great scheme of creation, we may fairly apply ourselves with a sure and +certain result of the most interesting discovery. Is it no hint that +wherever decaying organic matter is found, there do we find fungi? is it no +hint that they are found in all parts of the world? that even in snow the +germs of fungi will grow and multiply to such an extent, according to Capt. +Ross, that the protococcus was seen {120} by him, clothing the sides of the +mountains at Baffin's Bay, rising, according to his report, to the height +of several _hundred feet_, and extending to the distance of _eight miles_? + +Even stones contain in their interior, or interspaces of their structure, +the germs of fungi. A species of Tufa is found in the vicinity of Naples of +a porous texture, which, when moistened and shaded, produces vast +mushrooms, four or five inches high, and eight or ten inches broad.[47] +This author further says: "In the Maremma, where the volcanic tufa is the +basis of the soil the surface is intermixed with the animal remains of +departed empires, and the ordure of cattle, is covered with grasses of old +pasturages, and is wet with heavy dews. Everything, therefore, conspires +there to a fungiferous end." + +They are found growing in and upon both vegetables and animals. Nees von +Esenbeck imagined, that minute forms multiplied themselves in the +atmosphere; and really, when we consider the amount of effluvia composed of +the atoms cast off from the bodies of living or decaying organic matters, +which are incessantly passing into the atmosphere, the conjecture is not an +unreasonable one. The minuteness of those, which we know are always found +growing on decomposing bodies, does not preclude the possibility, nay, +further favours {121} the probability, that others infinitely more +minute,[48] may be destined to remove the more subtle and vaporous +particles which escape into the air. + +We can, therefore, I think, conclude, that the lower tribes of vegetation, +may consistently be regarded as capable of existing in almost any +condition, and almost under any circumstances, they may be made to grow in +plants by inoculation, as shewn by De Candolle, and Dr. Hassall. If the +stem of wheat also is inoculated with vibriones, they will make their +appearance in the grain.[49] If the seed contain them and have not lost its +germinating properties, these worms will be found again in the grain. If +the grain containing them be dried for years, and moistened again with +water, these animalcules, according to Bauer and Steinbach, will present +all the phenomena of life. This experiment I have witnessed, and can +confirm the statement. These animalcules in the diseased grain, have under +the microscope the appearance of an immense {122} number of eels crowded +together in a small space, and presenting a movement more, perhaps, +vermicular than any other, and it is continued for a considerable time. Now +if these animalcules, or their ova, can be proved to pass with the sap to +the seed, there can be no difficulty in comprehending how germs, +considerably more minute and of a vegetable nature, should be found subject +to the same peculiar mode of obtaining an entrance into animals and +vegetables for sustenance. "It is usually imagined," says Dr. Carpenter, +"that the germs liberated by one plant are taken up by the roots of others, +and being carried along the current of the sap, are deposited and +developed, where vegetation is most active." + +The chemical theory of disease would be better sustained by a comparison of +"the artificial formation of alkaloids," and the phenomena of +transformation of blood into the tissues of animals, and their degeneration +into effete matters, and of sap into the tissues of plants and their +degenerations. + +Professor Kopp of Strasburg, says, "In a chemical point of view, the +alkaloids are remarkable for their composition, for their special +properties, both physical and chemical, and for the interesting reactions +to which many of them give rise, when exposed to the influence of different +reagents. Considered medically, the organic bases are distinguished by +their energetic properties. They {123} constitute at the same time, the +most violent and sudden poisons, and the most valuable and heroic +remedies." + +Upon this very intricate and interesting part of chemical philosophy, it is +rather dangerous to enter without a thorough and practical knowledge of the +subject. This, however, falls to the lot of few men. We, who are engaged in +the study of disease, and of the best methods of cure, are obliged to take +the investigations of the analytical chemist, and examine them for +ourselves in the intervals of leisure allowed us during the active exercise +of our calling. Though with less advantages for the study of these +transcendental relations of organic and inorganic matter, we are not, +nevertheless, precluded from forming our opinions on their practical +bearings to the phenomena and treatment of disease. + +That there is a matter of a poisonous nature concerned in the production of +endemic and epidemic affections, cannot be doubted by any one; I believe +indeed, that the chemical theorists admit this, at all events Liebig does, +for he says, "The morbid poison changes in the blood are fermentative, just +such as occur in beer making." If we start, then, with the consideration +that poisons, in a chemical point of view, are the objects of our research; +the obvious course to take is to enquire what is the source of poisons +generally, and what their effects on the animal economy? The mineral +poisons are entirely excluded from the enquiry by their {124} inaptitude +for diffusion, and their uniform effects upon all persons, differing only +in degree in their operation. The same objections apply to gaseous poisons, +except that to them the property of diffusion would be admitted.[50] We +come then to the alkaloids, which constitute, as Kopp says, the most +violent and sudden poisons. For the production of alkaloids by artificial +means, organic products of some kind are required. Artificial heat, +powerful chemical agents or length of time, are, as far as information at +present extends, the indispensable requirements to induce these peculiar +changes in matter. The only instance I can find, in which elementary +matters can by artificial means be combined, so as to resemble the products +of nature, is that of the conversion of carbon and nitrogen into cyanogen. +But the process by which this is accomplished, leads rather to doubt +whether it be really and simply by a combination of _elementary_ carbon and +nitrogen. I extract the following from the Annual Report of the Progress of +Chemistry, for 1848. "H. Delbruck has performed some experiments on the +important subject of the formation of cyanogen. He confirms the statements +of Desfosses and Fownes, inasmuch as a _weak but distinct_ formation of +cyanogen was observed on igniting {125} _sugar-charcoal_[51] with carbonate +of potassa in an atmosphere of nitrogen." The use of sugar-charcoal, may be +perhaps an explanation of the weak formation of cyanogen, for in these +numerous and successive chemical changes of matter, it is impossible to say +how many sources of error may arise. The constant contradictions of each +other, and the opposite statements made by chemists, of equal eminence, +leave us in a wilderness of doubt, from which we are not likely to be +freed, until definite laws shall be discovered to act as a guide in the +comprehension of the higher branches of Chemical Philosophy. + +But supposing that the generation of alkaloids could take place in the +body, or some analogous poisonous matter, we have yet to imagine a whole +host of peculiar and essential conditions to effect this change, besides an +atmospheric agent or agents to set in motion those compositions and +decompositions, capable of bringing out these new products from the +elements of blood. We are aware that in the blood, carbon and nitrogen are +sufficiently abundant as well as saline compounds, to generate cyanides, +and, with hydrogen also there in plenty, hydrocyanates, and thus from them +many other poisonous products, but how is all this to be effected? And even +if effected, it is yet a question if such compounds can in any way simulate +the attacks of epidemic disease. We have {126} already shewn that the +amount of most poisons necessary to destroy an individual, can be pretty +clearly estimated, and their _modus operandi_ is tolerably well understood. +Again, the most essential part, in which all chemical theory fails, is an +explanation of the reproduction of contagious matter. + +The catalytic process, by which decompositions are said to be effected, and +in which Liebig includes the various fermentations, is one of those +chemical relations of matter to matter, considered by some as the probable +cause of infection. Mr. Simon, in a late lecture, has said, "I consider the +phenomena of infective diseases, to be essentially chemical, and I look to +chemistry to enlighten the darkness of their pathology. Qualitative +modifications, affecting the molecules of matter as to their modes of +action and reaction, are such as form the subject of chemical science; and +those humoral changes which arise as the result of infection clearly fall +within the terms of its definitions." Further on he adds: "The phenomena of +infected diseases appears then, in many respects, to be sui generis. +Certainly they are chemical. _Probably_ they belong to that _class_ of +chemical actions called _catalytic_."[52] + +{127} + +It is not improbable that something resembling a catalytic action may take +place in the blood in those diseases of endemic and epidemic origin, but +that it can be by a chemical process alone is contrary to all experience of +catalytic operations, for except in the instance of fermentation proper, +there is no multiplication of the fermentative matter. The action of the +matter of contagion seems to stand on the confines between electro-chemical +and bio-chemical manifestations, and so long as no chemical explanation can +be given for the multiplication of the matter of infection, the most +rational course to adopt is to assume that life under some unknown form is, +as we every where find it, the sole reproductive agent. + + * * * * * + +{128} + +SECTION II. + +THE ANIMALCULAR THEORY OF EPIDEMICS UNTENABLE. + +The animalcular theory of disease, after remaining almost unnoticed for +nearly two centuries, has been again revived under the auspices of Dr. +Holland in this country, and Henle of Berlin. And though not entirely +buried in obscurity, this theory had completely failed to modify the +practice of physicians in the treatment of those diseases which were +supposed to owe their existence to these invisible atoms of created being. +The resuscitated notions and all their amplifications, to which the advance +of science has contributed so much, are threatened with a like fate, an +absence of all practical results. + +Though I would not attempt to deny the possibility, nay, even the +probability, that insect life may yet be discovered as the cause of some +diseases,[53] still {129} there are many and cogent reasons against both, +and which are at variance with facts and observations. Where insect life +has been found associated with disease, it more especially appears as a +consequence than as a cause. + +Disease, in its most enlarged sense, is a conversion of one form of matter +into another; it is a transformation of healthy blood and tissue into new +and abnormal products. Where insects in all their variety of forms are +discovered, their voracious propensities are their chief characteristics, +they are the consumers of matter after its partial disintegration, if +animal matter be their food, unless they be carnivorous and predacious, or +if herbivorous they usually feed upon the tender shoots of plants. Thus far +we are certain of the manner in which insects destroy living matter; it is +a process the unassisted eye may every where witness, and which experience +has amply attested. To take, however, the animalcular world as it presents +itself to us under the microscope, and as the intermediate step between the +manifest and the hidden for a fairer and more direct method of reaching the +truth, what do we observe to be the ruling law of infusory instinct? They +live to feed; the term polygastrica sufficiently implies their natural +tendency to consume. The simplest form of animalcular life, seen in the +genera of monads, still preserves the animal character by possessing a +stomach or stomachs in which the food is received, to be digested for the +nourishment of the {130} system; and even some of these minute objects +which vary in size from one _two-thousandth_, to one _three-thousandth_ of +a line in diameter, are said to be carnivorous and predacious. Upon this +fact alone, I would place the improbability of insects being the cause of +epidemic disease. Each insect doubtless has its own peculiar food, and +whether it be a vegetable or animal feeder, it consumes the matter already +organized for conversion into its own tissue, and the only change which +could be affected by them in the blood, would necessarily be that of +appropriation of some one of the constituents as an element of food; when +that food is digested, (taking digestion generally as an identical +process,) the excrementitious matter is composed of secretions and +disorganized matter, mixed together as an _effete_ product, and destined +then for reorganization by the vegetable kingdom. Now all animals, whether +they be large or small, live on organized matter,--they convert that matter +into an inorganic form, and I cannot help imagining that if epidemic +diseases and fevers depended upon animalcular growth and development in the +blood or tissues of the body, the excretions or secretions from them would +have yielded some information to the searching enquiries of the chemist, +supposing that these excretions and secretions were capable of reaching to +a sufficient amount in quantity, to bring about those fatal effects of +poisoning, we witness in Cholera and other epidemic affections. Insects, I +{131} believe are poisonous only by their secretions, and though they are +known to multiply with exceeding rapidity, I can hardly imagine that by +their development, however rapid, they could produce such a change in the +human body, as to bring about the speedy dissolution, and generally +gangrenous appearance, that has invariably been observed in those suddenly +dying under the influence of epidemic poisons. The vibriones, whose +destructive effects on wheat are so well known, are a genus of animalcules, +which at first would seem to favour the animalcular theory in a remarkable +manner; for on examining them, they do not appear to possess any other +structure than a gelatinous absorbing mass, in this respect resembling a +vegetable. + +But Ehrenberg's scrutiny corrected the error of De Blanville, and shewed, +that they were far from being agastria, or stomachless animals. The Rev. +William Kirby says, "Ehrenberg has studied the vibriones in almost every +climate, and has discovered, by keeping them in coloured waters, that they +are not the simple animals that Lamarck and others supposed, and that +almost all have a mouth and digestive organs, and that numbers of them have +many stomachs." All the discoveries indeed which have been made on the +minuter forms of animal life, have tended to confirm the doctrine that the +stomach is the exponent organ of an animal; that is, in all animals there +exists, in a variety of modified conditions, a receptacle for food. Some of +the {132} animalcules, however, are still supposed to exist by absorption, +as the vinegar eel, _vibrio anguilla_,[54] but when we find that the law +is, generally speaking, that the receptacles of food become multiplied in +number in these minute beings, and the vibriones which were supposed to be +stomachless, have been proved to emulate their associates in the number of +these organs; it would be more reasonable to conclude that our imperfect +vision is the barrier to their detection, rather than to suppose that they +do not exist. Besides, when we are told on undoubted authority that some of +the animals of this class, have as many as _forty or fifty_ stomachs; the +least we can do, is to allow that all of them possess, at least one +digestive organ, though we may not be able to detect it.[55] + +So far then for the consideration of animalcular structure: let us now more +particularly enquire into their destructive habits, and their functions, +inasmuch {133} as they may be supposed capable of engendering epidemic +diseases and fever. The truly carnivorous animalcules, or those truly +herbivorous in their instincts, we may presume to be beyond the limits of +our enquiry. We have rather to do with those which take an intermediate +position, namely, those which feed upon matter undergoing decomposition, or +upon fluids containing organic matters in solution, or suspension. If we +take Entozoa generally, they may be considered as most conveniently to be +placed in this intermediate class; and here we find still the digestive +apparatus, and more than this,--for upon the modifications of the organs +appropriated to digestion is their classification founded. "Rudolphi +divided the Entozoa into Sterelmintha, or those in which the nutrient tubes +without anal outlet are simply excavated in the general parenchyma, and +into the Coelelmintha, in which an intestinal canal with proper parietes +floats in a distinct abdominal cavity, and has a separate outlet for the +excrements."[56] + +How do these animals obtain their sustenance, and what changes can they +produce upon the vital fluid of the body? Analogy is here our only guide. +If the trichina spiralis is examined, it is found to be enclosed in a cyst +containing fluid; and this is, {134} doubtless, the source of its +nutriment, and contains in solution the elements for its nutrition; but in +this instance there is no selection, and there can be no locomotion to an +extent sufficient to imply searching for food, as the animalcule in its +natural state, when taken from the human muscle, is found coiled upon +itself, making about two and a half turns. The fluid of the cyst is thus in +all likelihood prepared by endosmosis, for the immediate and appropriate +nutrition of the parasite. The cyst is thus the part which performs the +diseased process, the containing animalcule is merely the consumer of what +is prepared for it by the cyst. And this would seem to be the rule with all +parasites, of the encysted kind. + +We have alluded to the vibriones which are found in the fluids of living +bodies, and the trichina which is found in the solid muscle; we have now to +refer to those which infest the cavities. It was, I believe, Ehrenberg, who +shewed that the tartar which accumulates on the teeth is composed of the +debris of minute animalcules; in fact, that it consists of calcareous +matter, having once formed a portion of the structure of their bodies, the +ubiquity of these creatures is therefore as much and clearly established as +the lower forms of vegetation. The intestinal worms, of which perhaps the +Taenia is the most curious and important to be noticed, are from the +locality in which they are found, chiefly injurious by the irritation they +set up, and by appropriating {135} to themselves the nutrient juices +elaborated in the process of animal digestion, thus depriving the +individuals they infest of that which was destined for their own +nourishment. In this, as in all associated instances, the character by +which these parasitic animals are marked is their consuming propensity. +There is, however, one more observation to make upon parasitic growths; but +the question is yet unsettled in what kingdom of nature is the +acephalocyst, or hydatid, to be placed. Mr. Owen says, "As the best +observers agree in stating, that the acephalocyst is impassive under the +application of stimuli of any kind, and manifests no contractile power, +either partial or general, save such as results from elasticity, in short, +neither feels nor moves, it cannot, as the animal kingdom is at present +characterized, be referred to that division of organic nature." + +We thus arrive at the simple cell, and the multiplication of living beings +by cell buds; it is the point at which the confines of the animal kingdom +are reached, and at which we are driven to speculation. The hydatid lives +like a plant, by imbibition; and procreates, like a plant, by budding, +either endogenously or exogenously, as regards the original or parent +cell.[57] + +{136} + +This condition of being, suggested the notion of Protozoa, or first +animals, in the same way that the purely cellular plants, that is, each +individual, consisting of a single cell, gave the idea of Protophyta, or +first plants. Mr. Kirby thus expresses himself on this subject: "The first +plants, and the first animals, are scarcely more than animated molecules, +and appear analogues of each other; and those above them in each kingdom +represent jointed fibrils." + +Admitting, then, that animals as well as plants exist in the form of simple +cells, and that their multiplication proceeds apparently upon the same +principle in each, it is nevertheless abundantly manifest, that the +cellular form of perfect individuals is infinitely more numerous in the +vegetable than in the animal kingdom. + +{137} + +From the mosses downwards to the fungi, the whole structure of the plants +consists of an aggregation of cells, more or less in number and complicate +arrangement, until, through a variety of gradations, we reach the single +cell as a perfect individual. + +It is rather remarkable, that the lower forms of vegetables and animals +seem to derive their nutriment from matter of a similar kind; and though +the office of plants is as a rule, to convert inorganic into organized +matter, it appears that some of the fungi may live as animals do on organic +matter when in a state of solution. This, however, is uncertain; for we do +not know what are the first signs of decomposition in organized bodies, and +for aught we can tell, it may be perpetually going on; so far as the +disengagement of carbon from the system is concerned, this is certain; but +whether the nitrogenous compounds also are subject to a resolution into +their elements in the living body, is another question, and not so easy of +solution. The partially decomposed elements of animal structures are, +however, particularly adapted for the nutrition of the lower forms of +vegetation; it is, indeed, from the decaying organic matters that the fungi +derive, it may be said, their entire food. + + * * * * * + +{138} + +SECTION III. + +SKETCH OF THE PHYSIOLOGY AND PATHOLOGY OF PLANTS AND ANIMALS. + +Animals and plants depend for their existence upon a nutritive fluid, which +permeates their structure; it is the element from which all their +secretions are formed, and their organs are nourished. + +The food of animals is composed of previously organized matters, and is +conveyed into a reservoir called a stomach, where it undergoes a process of +solution, previously to entering the circulation. At this period, the +animal and the plant again present points of resemblance, the lymphatics or +absorbent vessels take up the products of digestion, and convey them to the +blood-vessels, where mingling with the current of the blood, they are +conveyed to the lungs, there to undergo a process of oxygenation before +they become fitted for the renovation of the tissues of the body. Such is +the nature of the food of man, that it contains all the elements necessary +and adapted for transformation into bone, muscle, brain, and parenchyma, as +well as the other tissues of the body; besides other elementary matters, +which, though they form a very insignificant portion of {139} animal +textures, from their constant presence in the vital fluid, evidently +perform some important offices in the general economy of life; they are +partly, perhaps, occupied in forming constituents of secretions. + +Plants do not require a stomach,--the humus or soil to which they are fixed +is the laboratory, where the nutritive matter is prepared in a state fit +for absorption by the spongioles of their roots, and these correspond to +the lymphatics of animals; after being taken up by the spongioles, this new +fluid mingles with the sap, and passes to the leaves or breathing apparatus +of plants, where carbonic acid gas combines with the crude vital liquid, +and converts it into a condition fit for all the offices to be performed by +the plant: viz. the growth of tissues, and the elaboration of secretions. + +The tissues, however, of plants, though more simple in their nature, +present a much more varied character than those of animals, when the +different species are compared. + +The bones of animals which give them their form, are invariably constituted +of phosphate and carbonate of lime, deposited in a matrix of gluten; +muscle, nerve, brain, tendons, and ligaments, have nearly, if not +completely, an identical composition throughout the whole range of the +animal kingdom: their secretions, however, vary much more considerably, as +also do the secretions of vegetables. But vegetable tissue may contain, as +in the stems of {140} grasses, a considerable amount of silex, and some +notable quantity of sulphur, and so essential to their existence is the +former element, that they cannot live without its presence in the soil, and +also with it an alkali, to render it soluble. A large amount of soda, is an +invariable attendant upon the structure of marine plants, as potash is of +those growing on the land. + +Thus, whether we regard the health of animals, or vegetables, we discover, +that besides the matters which are absolutely indispensable for the +nutriment of the tissues which undergo rapid transformation, those of a +more permanent and durable nature require in an almost insensible degree, a +restitution of elements; and though not apparently absolutely necessary to +preserve vitality in the being, yet have so marked an influence over it, as +to indicate an extensive bearing of each individual part, on the whole +associated entity. + +The elementary tissues of both kingdoms have been traced, in whatever form +they may be found, to a cellular origin. The minutest vegetable germ, is a +cell containing a granular matter within it, and even man himself, in his +embryonic state, may be represented as an insignificant point in the realms +of space; and might be placed side by side with the smallest particle of +living matter, without suffering by the comparison. + +The laws by which the development of these elementary cells is regulated, +so that each advances {141} to its limit, and fulfils its destination, is +one of those inscrutable and overwhelming mysteries of nature, which leads +the admirer of creation on and on into the abyss of the future, and fills +his soul with aspirations for that time, when the veil of ignorance shall +be withdrawn. But this is not my subject. + +The organization of the two animated kingdoms, is then regulated by +definite laws, and all matter, whether acting upon them as agents of +nutrition or destruction, are equally under their dominion; to investigate +and to endeavour to fathom some of these laws, is the aim I have in view. + +The sap is to the plant, what the blood is to the animal,--the elements of +nutrition and secretion are contained in it, and whatever interferes with +its normal constitution by subtracting from, or adding to it, deteriorates +its qualities, and retards or accelerates the functions of the individual. +Excess or deficiency of the natural elements may also be a source of +disturbance; if carbonic acid be too abundantly liberated in the soil, as +Dr. Lindley expresses it, "plants become gorged;" and if, on the other +hand, the elimination be too slow, they become starved. It has been also +shewn, that plants though they give out oxygen from their leaves, do not +throw it off as animals do carbonic acid from their lungs; but that this +arises as a result of digestion, and the fixation of carbon in the system, +and that they really respire oxygen as {142} animals do, and give off +carbonic acid, both by day and night. + +That light is the stimulant of the digestive functions, and that, +therefore, during the day, the amount of oxygen thrown off, far exceeds the +amount of carbonic acid liberated during the same period. + +The great and important distinction between animals and plants is, that the +former possess a nervous system, by which they are subject to a very +extended series of psychological relations; it is in these chiefly, if not +entirely, that we are to look for the distinctive and well-marked +differences of diseased action. In animals there are special media of +communication between the sources of dynamic power, and the parts upon +which the force is exercised: and again, a return communication exists, +which conveys impressions to the source of power, and to use a simple +comparison, a system of telegraphing is in incessant and watchful +operation. This force is influenced and modified in its action, when +exercised in the regulation of nutrition, growth, and reproduction of +tissues, by the passions and emotions of the mind. All the secretions and +functions of the body are more or less susceptible of being accelerated, +retarded or modified by the psychical relations of mind and matter. Though +we are apt to imagine that in man alone, these phenomena obtain much +importance--there can be but little doubt, that wherever a {143} nervous +system exists, whether in the form of aggregated or diffused ganglia, the +interdependence of force and organization, each upon the other, bears a +certain and definite physiological comparison; the more aggregated the +ganglia, the more close, intimate, and extensive the psychical connexions, +and the gradations pass downwards, until they appear to be lost on the +confines of the vegetable kingdom. + +The diseases of plants and animals deserve a more careful comparison than, +I think, has hitherto been bestowed upon them.[58] If the study of +physiology, or an enquiry into the laws which regulate the functions of +living beings in a state of health, has been materially aided by the +intimate knowledge of vegetable physiology, which, from the simple +structure of plants, so favours the experiments of the student, there is +every reason to suppose that vegetable pathology may also lead us to an +equally important and useful result. + +It is quite certain, that if a healthy seed, or leaf-bud, be placed in such +a situation, that, according to the laws known, it will in all likelihood +germinate, if all the elements for its sustenance exist in the soil, and +the temperature and hygrometric {144} condition of the atmosphere are +adapted to it, a healthy plant will be the result. Light, heat, moisture, +and soil are therefore to be considered as the agents required to exist in +a certain balance, or proportion, in reference to the health or power of +vitality of the plant. Within a certain amount of variation, health may +persist in virtue of the power of selection, which appertains to the +spongioles of the root in absorbing nutriment; and also as regards light, +from the tendency which most plants have to accommodate themselves to any +deficiency of this element, by presenting their leafy expansion in that +direction where the most of its influence may be obtained. But beyond a +certain limit an unhealthy condition sets in. If the soil contain not the +inorganic elements, which are absolutely indispensable for the tissues of +the plant, or even if they be there and not in a state to be absorbed, a +dwindling and degeneration ensue; if light be deficient in quantity, +pallor, feebleness, and elongation of tissue follow, with more fluidity and +general softness of texture. These conditions of plants have their +analogues in the ill-fed and ill-nourished children in some of our +manufacturing districts; they are stunted and diseased. Transport a healthy +country lad, with the bloom of health on his cheek, from his native hills +and valleys, or woods and fields, to the stool behind a desk for eight +hours a day, in a narrow street in any city, where the rays of the sun +rarely penetrate, it will not be long before {145} the skin of the animal +and the cuticle of the plant may be submitted for comparison, when both +will testify to the importance of the solar rays, as an indispensable agent +in supporting the normal processes of organic life. So far common +observation is competent to a solution of the facts; but beyond this we +come to the enquiry, what resemblances are there in the early conditions of +plants and animals. Each originates from nucleated cells, endowed by the +All-seeing Power with a blind impulse of progressive development; the most +simple cell of a vegetable multiplies itself by a generation of new cells +within it, when the parent dies, and liberates the offspring. Here +progression is simply multiplication; it is, as it were, progression in +length only. The original cell, however, of animals, which is styled the +germinal vesicle, extends or becomes developed into dissimilar parts; and +whatever may be the variety, all alike proceed from the original germ cell, +and the _tout ensemble_ of parts constitutes the one and indivisible whole; +in this instance there is addition besides multiplication, tissues and +organs are added in all variety, until the maximum of organic development +is attained in the wonderful being, man. + +Yet how many points of resemblance are there between the vegetable cell and +the fully developed human being, in a physiological and pathological point +of view. There must be nourishment to sustain both; both require a certain +amount of light {146} and heat for their growth and increase, and are +dependent upon various unknown causes for active and healthy existence; and +when a certain time has expired, all alike return to a condition, in which +the particles composing them are subject only to the dominion of the laws +which preside over inorganic matter. + +But during the existence of plants and animals, we discover other features +of comparison; plants, as well as animals, are liable to disease; they are +subject to functional and organic affections. The former, among plants, are +usually traceable to atmospheric vicissitudes or irregularities, changes of +situation, &c.; and in man to irregularities of diet, and mental and bodily +excesses, as well as to atmospheric vicissitudes.[59] + +The organic diseases of plants and animals depend upon a repetition, or +continuance, of functional derangement. As a consequence of this, the +nutrition and reproduction of tissues lose their normal and definite +character, wherefrom an indefinite and abnormal result is obtained. There +is a limit to abnormal productions, and they are apparently {147} subject +to laws, though not yet understood. In animals, they may be either +excessive development of natural tissue in natural localities, as obesity +and fatty tumours; they may be natural products in unnatural situations, as +fatty degenerations of muscular tissue; or altogether new and unnatural +products, as tubercle and cancer. + +In plants, from their greater simplicity of structure, organic affections +are perhaps entirely limited to the two first forms of animal organic +disease; viz. to undue development of tissue in natural situations, and to +the formation of natural tissue in parts of a plant where they are not +usually found in a state of nature. The variety of excrescences seen on the +stems, branches, and twigs of plants, may be given as instances of the +former; and the conversion of stamina into petals, as in double flowers, as +an instance of the latter. + +We derive our sustenance from vegetables, and they from us; they produce +for us the soothing opiate and the deadly strychnia; we for them the +animating ammonia, and the distortions and sterility of excessive culture; +we engender in them, by the latter, debility, disease, and death; and in +our turn we become their prey. All this indeed is but a cycle of events, +that requires no learned mind to fathom, and to comprehend; it is a matter +of every day occurrence, and, though perhaps not entirely unheeded, is not +dwelt upon in the fulness of its bearings and importance. {148} + +Let us now consider the diseases of plants, as a study progressive to those +of man; and as their physiology has so extensively served us, we may +possibly also find in their pathology much material for instruction; not +that it will be attempted to shew that the same diseases affect both +kingdoms, but that diseases, though dissimilar in effects, may have similar +sources. + +Unfortunately, there are not many men in this country, who need go further +than their own gardens to find abundance of disease among their fruit trees +and vegetables. The vine, the apple and the potato, common to most gardens, +will furnish specimens. + +It is an error of a serious kind to suppose, that the parasites which +infest plants are not essentially the cause, or, perhaps, more properly +speaking, the elements of disease. I confine myself here to disease of +parasitic origin, as that is the subject of which I am chiefly treating. + +That parasitic growths are the elements of disease in some instances, is +now beyond dispute. The experiments of Mr. Hassall, detailed in Part II. of +the Transactions of the Microscopical Society of London, are most +conclusive; and they are of that simple nature, that any one may convince +himself of their accuracy, by a repetition of them from the directions +there laid down. + +He says, the decay is communicable at will "to any fruits of the apple and +peach kind, no matter {149} how strong their vital energies may be, by the +simple act of inoculation of the sound fruit with a portion of decayed +matter, containing filaments of the fungi. We may use with success the +sporules of such fungi; but in this case the decomposition does not set in +so quickly; in the one case, the smaller filaments of the fungi have +advanced several stages in their growth; while in the other, the sporules +have yet to pass through the several stages of their development." + +Mr. Hassan, however, seems to speak doubtfully as to the mode in which the +disease becomes naturally introduced;[60] how the spores enter the fruit, +"is not very clear--though probably, it is by insinuating themselves +between the cells of which the cuticle is composed, or perhaps by means of +the stomata, where they are present. I may here state that the experiments +were made on fruit, while living, and attached to the tree." + +But why should there be a doubt as to the parts by which the sporules of +minute fungi enter the plant, when it is clear, that not only can they +enter {150} by the spongioles, but by the stomata of the leaves, and mingle +with the sap. It is true, that they make their appearance and grow upon the +leaves and the fruit; but these are the situations most adapted for their +fructification. I have seen the spores of the fungi which attack the +cucumber and vegetable-marrow, in the cells of the hairs, and even their +filamentous prolongations; these appropriate the fluids conveyed to the +cells of the hair, rupture them, and at length fructify. + +On referring to Dr. Lindley's Medical and Economic Botany, I find that many +fungi are the active elements of disease, and in a manner which renders it +highly improbable that they are so in any other way, than by obtaining an +entrance to the sap of the plants. Of the microscopic fungus which destroys +wheat, the Uredo caries of De Candolle, we find the habitat to be within +the ovary of the corn, and that 4,000,000 may be contained in a grain of +wheat,--now this and another fungus, the Lanosa nivalis, are said to +destroy whole crops of corn: we cannot imagine that such an extensive +affection, can have any other source than by means of the spores through +the sap, seeing that bruising of the surface, or rupture of the cuticle of +the apple, a comparatively soft fruit is necessary to produce the disease +artificially in them; besides, a grain of corn containing vibriones, when +grown and having fruited, the new fruit also contains them--now here, as +this is I believe almost invariably the {151} case, either they or their +ova must be carried with the sap to the new germs. + +It is rather a remarkable fact, that these entophytes appropriate the +nutriment destined for the plant in which they grow, they are consequently +the means in many instances of its entire destruction, though only +partially so in others. + +There are many Fungi which have this tendency. The Puccinia gramienis, +"preys upon the juices of plants, and prevents the grain from swelling." +The Aecidium urticae, common on nettles, deprives the plant on which it +grows, of the organizable matter, intended for its own nutrition. The +Erysiphe communis, overruns and destroys peas. The Botrytis infestans, +"attacks the leaves and stems of potatoes." The Oidium abortifaciens, +attacks the ovaries of grasses--and the Oidium Tuckeri, "a formidable +parasite, destroys the functions of the skin, of the parts it attacks." The +latter has been most injurious to the vines, during the last two years. I +have known instances in which the vines have been cut down, and every means +taken to rid the houses of the disease; but this year, it has made its +appearance, with all its former virulence, in the new shoots. + +This, however, is sufficient to shew that plants are liable to disease, +depending upon parasitic growths, which affect their vital powers, and +deprive them of their natural nutritive fluids. + +But somewhat similar diseases belong also to {152} warm climates; in a +letter from Cuba, dated Dec. 1843,--Mr. Bastian writes, "_a plague_ has +appeared among the orange trees--a mildew attacking the leaves and the +blossoms, which finally dry up. It most frequently kills the trees. None of +the orange family are exempt; lemons, limes, and their varieties, with the +shaddock and forbidden fruit, have all suffered." This disease has +continued without intermission, till the present year,--when the same +gentleman writes, Feb. 20th, 1850: "The evil exists, although in a +diminished degree, so much so, as to have allowed the trees to produce me +30,000 oranges again. In old times, the same plantations produced me +100,000." + +The West India sugar-canes are also liable to a disease, which the Rev. Mr. +Griffiths, in his Natural History of the Island of Barbadoes, speaks of, in +the following manner: "This, among diseases peculiar to canes, as among +those which happen to men, too justly claims the horrible precedence." This +disease is called the Yellow Blast. It is difficult to distinguish the +Blast in its infancy, from the effect of dry weather. + +There are often seen on such sickly canes, many small protuberant knobs, of +a soft downy substance. It is likewise observable, that such blades will be +full of brownish decaying spots. The disease is very destructive to the +canes. It is observed, that the Blast usually appears successively in the +same fields, and often in the very same spot of land. {153} + +This Blast is often found far from "infected places," and the infection +always spreads faster to the leeward, or with the wind. + +"_It is remarkable if canes_ have been once infected with the Blast, +although they afterwards to all appearance, seem to recover; yet the juice +of such canes will neither afford so much sugar, nor so good of its kind, +as if obtained from canes which were never infected." + +I may here allude to the circumstance, that in the island of Cuba, the +destructive mildew is commonly called, _la pesta_. + +It were needless to multiply instances of other endemic and epidemic +diseases of vegetables; they are well known by practical observers to be +very numerous, and I believe, in most instances, depending upon fungoid +growths. The destruction of vegetables by insects, is of a very different +nature to that produced by the fungi; it would be as unreasonable to +consider the consumption of corn and herbage by locusts, as a disease of +vegetation, as the massacre and devouring of human beings by cannibals, a +disease of the human body. + +It is true that insects are exceedingly destructive to plants, but as far +as I am able to obtain information, they appear to be so chiefly by their +voracious propensities; they consume the structure of the plant in its +entity, and do not primarily interfere with its vitality. The instance of +the vibriones, before-mentioned, seems at first to be an exception {154} to +the rule, but this is rather apparent, than real; and it may be made to +apply more as a confirmation, than an obstacle to the vegetable theory: for +if we may fairly compare the diseases of animals with those of plants, the +existence of entozoa in the latter, would be considered an essential point +to be substantiated. + +Having now considered the question as to the infeasibility of supposing +that chemical fermentation is the basis upon which a theory of diseases can +be sustained, and having shewn that life is inseparable from infection, and +miasmatic generation;--having explained the phenomena of the dispersion of +diseases by comparison with the dispersion of plants, and finally, having +demonstrated that the physiology and pathology of plants bear so close a +relation to each other, and that their epidemic affections depend upon +minute organic germs, I submit to the judgment of my readers, whether there +is not much reasonableness in the application of the facts to the +inference--that living germs are the cause of epidemic disease in man and +animals. + + * * * * * + + +{155} + +CHAPTER IV. + +RESULTS IN PROOF OF THE TENABLENESS OF THE PROPOSITION. + +-------- + +SECTION I. + +OBSERVATIONS ON SOME OF THE LAWS OF EPIDEMIC DISEASES. + +The results obtained by comparing certain facts connected with Epidemic +Affections of animals, with analogous affections in plants, afford, from +the few instances I shall here notice, a very strong presumption, that +analogous causes operate in the production of these affections. I have +already quoted from Hecker, to shew that previously to, and during the +Epidemics of the Middle Ages, the minuter forms of animal and vegetable +life appeared to be called into existence, much more abundantly than usual; +that famines prevailed in consequence of failure of cereal crops, no doubt +depending then, as now, upon the various forms of fungiferous growth. I +cannot refrain quoting here, a passage or two from our old friend Virgil; +for he confirms not only the fact of peculiar showers in {156} connexion +with diseases, but he also refers to the rust of corn, thus: + + 150. "Mox et frumentis labor additus; ut mala culmos + Esset rubigo ... + ... Intereunt segetes." + + _Georg. 1._ + +Then: + + 311. "Quid tempestates autumni et sidera dicam? + + . . . . . . + + 322. "Saepe etiam[61] immensum coelo venit agmen aquarum + Et foedam glomerant tempestatem imbribus atris + Collectae ex alto nubes." + + _Georg. 1._ + +The occurrence of black showers in this country has been observed during +the present year, and I understand that in the fenny countries of the East, +the corn has suffered much from the Uredo. I am not mentioning the +circumstances as cause and effect, but merely to call attention to the +fact, that unusual phenomena of this kind have been generally associated +with disease of the animal and vegetable tribes. + +The same causes also predispose plants as well as animals, to epidemic +attacks of disease. The repeated observations in the public journals on the +subject of ventilation, drainage, and over-crowding, render all notice from +me needless, to shew that these, though they do not produce the diseases +{157} treated of, yet that under the influence of bad air, bad drainage, +and over-crowding, epidemics are fostered and spread. + +Lastly, says the Count Philippo R['e], "I would remark that if _bad +cultivation, and especially bad drainage, does not produce bunt or smut, it +is certain that those fields, the worst treated in these respects, suffer +the most from these diseases_." + +It has been remarked by many observers, that a greater fecundity has +attended upon Pestilences, and this has been proved by comparison, that the +births in proportion have far exceeded the ordinary limit.[62] In +juxtaposition with this observation, I will place the following, not as a +proof, but as a remark made quite independently of the subject of which I +am treating. "From the first the diseased ears are larger than the healthy +ones, and are sooner matured. What appears singular, but which I have not, +perhaps, sufficiently verified, is _that the seeds are more abundant than +in a sound ear_." + +{158} + +Now these are facts which require amplification, and if these two alone +should be shewn upon an extensive field of observation, to apply not only +to corn, but to other members of the vegetable kingdom, as I doubt not will +be the case, though I am not fully prepared to prove it, it would be +difficult to dissociate the fertility of the two living kingdoms from the +operations of one and the same, or an analogous law. + +The epidemic diseases of plants are both infectious and contagious, at +times they are observed to be endemic only, and then depending particularly +upon some local causes. This is a law of diseases which applies equally to +those of men and animals. In connexion with this law is another, which, as +far as I am aware, has not hitherto been noticed in connexion with plants. +The potato disease, which excited so much interest and created so much +anxiety for the poorer classes of society, led the Government of this +country to employ the most learned men to investigate the subject, in the +hope of propounding some reasons which should explain the cause of the +calamity, and thereby deduce a method of eradicating the evil, or, in other +words, discover a cure for the disease. Many were the opinions as to the +cause of the distemper, which it were useless here to recount, but a method +was suggested, to which most people, I believe, looked forward with great +anticipations, and this was to obtain native seed, and to sow it on virgin +soil. Was the end accomplished? No. {159} For though the seed was sown, and +the plants grew, the disease still appeared among the newly imported +individuals, to as great an extent, as among the native or domesticated +plants. + +As a parallel to this, it may be stated, that, as regards either endemic or +epidemic disease, those persons newly arrived, either in a district or +country where these prevail, are even more liable to them than the +residents.[63] Again, I have learned, that where the potato disease has +been so bad as to render the crop almost valueless, the best plan to be +adopted is, to allow the plants to remain in the earth, and thus leave such +as retain their germinating powers to come up spontaneously the following +year. I certainly saw one large field treated in this way, yield a crop +almost without disease. + +{160} + +The seasoning, in this instance, seems to bear a comparison with the +seasoning of animals and man, under a variety of diseases, which for a time +renders them insusceptible of another attack. It therefore does not appear +so improbable, that these affections may be regarded, as Unger, the German +botanist supposed, the Exanthemata, or Eruptive Fevers of vegetables. + +Another feature seems to associate the Epidemics of plants and animals, in +a manner suggestive of analogous causes operating in both instances. + +The lungs of animals and the leaves of vegetables, are their respiratory +organs, by means of which, the blood in the one case and the sap in the +other, derive gas from the air, and impart gas to it, each taking what is +thrown off by the other. + +Now the epidemics among vegetables, have a remarkable tendency to exhibit +their effects primarily on the leaves, and particularly on those parts +which are appropriated to the function of respiration. It is from the +stomates that many of the fungi commence to germinate, and their +fructification may be seen sprouting from the opening composed of a chink, +surrounded by a peculiar arrangement of cells, which constitute the +breathing apparatus of their victim. + +In the earlier epidemics, of which we read, one of the most remarkable +circumstances, was the extraordinary influence the poisonous matter +appeared to {161} exercise over the lungs,[64] and they again, were the +means of propagating the disease, and spreading the contagious particles +through the atmosphere, for we read: "Thus did the plague rage in Avignon +for six or eight weeks, and the pestilential breath of the sick, who +expectorated blood, caused a terrible contagion far and near, for even the +vicinity of those who had fallen ill of plague was certain death; so that +parents abandoned their infected children, and all the ties of kindred were +dissolved."[65] "The like was seen in Egypt. Here also inflammation of the +lungs was predominant." "Here too the _breath_ of the sick spread a deadly +contagion." + +It is more than probable that all infectious matter obtains an entrance to +the system through the lungs. Inspiring the air containing the pestilential +semina is, indeed, the only plausible explanation of infection; for though +the skin is indubitably an absorbing {162} surface, and capable of taking +up and conveying to the blood any noxious matter applied to it, yet it is +far more probable that the lungs would effect this process with greater +rapidity. Then the stomach, the only other absorbing surface to which +extraneous matter can be applied, is not likely to be the part where the +elements of disease would obtain an entrance to the system, for many facts +prove, that infectious matter may be swallowed without any injurious +consequences, unless in a very concentrated state. Instances are not easily +found of diseased matter having been swallowed, except where diseased +vegetables have formed under some combination of circumstances, a portion +of diet.[66] + +Many facts are on record which prove the powerful effect of diseased grain +when made into bread, and taken for any length time as a principal article +of food. The history of Ergot of Rye is too fresh in the memory of most +people to require more than an allusion here. The stomach had no power over +the secale, its poisonous properties were retained, after having been +submitted to the digestive process, as was evidenced by the abortions and +gangrenes it occasioned. + +But diseased wheat is also capable of inducing {163} gangrene, and it is +more than probable, that many diseases might be traced to the use of +infected grain of various kinds. An interesting account of a family who +lived at Wattisham, near Stowmarket, in Suffolk, and all of whom suffered +more or less from living on bread made of smutty wheat, may be found in the +Philosophical Transactions. The mother of this family and five of the +children, consisting of three girls and two boys, all suffered from +gangrene of the extremities; the father lost the nails from his hands, and +had ulceration of two of his fingers.[67] Dr. Woollaston wrote thus in a +letter on this case: "The corn with which they made their bread was +certainly very bad: it was wheat that had been cut in a rainy season, and +had lain on the ground till many of the grains were black and totally +decayed, but many other poor families in the same village made use of the +same corn without receiving any injury from it. One man lost the use of his +arm for some time, and still imagines himself that he was afflicted with +the same disorder as Downing's family." It is not unlikely this was the +case, for numbness and loss of power was one of the well marked characters +of the disease. + +What other afflictions may be due to diseased vegetation and adulterated +articles of food, and what loss of life may accrue from cheap and +adulterated {164} drugs and chemicals is hardly yet dreamt of.[68] The +systematic practice of adulteration of almost every article of diet which +comes to table has become a serious question for the legislature to +consider. Take only the article of milk, upon which the young children of +large towns and cities, make their chief meals, with the addition of bread. +How much milk comes into London from the country, how much is obtained from +stall and grain-fed cows in the metropolis, and how much is said to be +consumed, would be an interesting calculation. It is pretty well known that +a mixture is sold by which a retailer of milk may increase his supply by +one-third or one-half. It was discovered in Paris that the brains of +animals, when prepared in a particular manner, formed, when mixed with a +certain proportion of milk and water, a very fine and deceptive cream; in +that city this system was carried on to a considerable extent. I could not +help alluding to these facts while speaking of diseased grain, for who +shall say to what extent a miller in a large way of business, may be able +to "work in," as it is called, a considerable amount of smutty corn in the +manufacture of flour? Now, as diseased grain is known {165} to induce +abortion, it is impossible to tell how small a portion may in some cases +produce the effect; we may therefore say with Thomas of Malmesbury, "There +is no action of man in this life which is not the beginning of so long a +chain of consequences, as that no human providence is high enough to give +us a prospect to the end."[69] + +To return,--associated with these observations are other facts of +considerable weight. Before and during pestilences, abortions are more +frequent than in ordinary times; infectious and contagious diseases induce +abortion; besides this, and independently of disease, conditions of the +atmosphere have been known to exist when abortion has been an epidemic +affection; of this Dr. Copland says, "to certain states of the atmosphere +only can be attributed those frequent abortions sometimes observed which +have even assumed an epidemic form, and of which Hippocrates, Fischer, +Tessier, Desormeaux, and others have made mention." With this reference I +will close the subject of comparison between the affections of the +breathing apparatus in animals and plants, merely alluding to the +probability that under some conditions of atmosphere, independently of +heat, &c. vegetables without any other assignable cause will become +abortive. + + * * * * * + +{166} + +SECTION II. + +WHAT IS THE NATURE OF THOSE POISONS WHICH MOST RESEMBLE THE MORBID POISONS +IN THEIR EFFECTS ON THE BODY? + +In the early part of this book, I considered the nature of poisons +generally, and had occasion to remark upon the characters which separated +poisons into two distinct classes. 1st, Those which have the power of self +multiplication; and 2nd, Those destitute of this property. + +Of the first we have seen that the poisons of epidemic diseases multiply +both in and out of the body. + +The poisons of infectious diseases, not usually epidemic, do the same. +Those of endemic affections, such as ague and some fevers, usually become +multiplied out of the body only, but under some circumstances, and peculiar +atmospheric conditions, they may be also multiplied within the body. The +amount of these poisons necessary to produce their specific effects, may be +inappreciable. Of the second class, there are two kinds, those derived from +the organic kingdom and those derived from the inorganic kingdom. Of these, +the amount necessary to produce their specific effects is appreciable and +pretty well known. + +But among those poisons, consisting of organic {167} products, there is one +which seems to hold an intermediate place. This is derived from one of the +Fungals, and as it takes this remarkable position as a link of connexion +between the two classes of poisons, I may be excused quoting a passage of +some length upon this agent, from Dr. Lindley's Vegetable Kingdom. "One of +the most poisonous of our fungi, is the Amanita muscaria, so called from +its power of killing flies, when steeped in milk. Even this is eaten in +Kamchatka, with no other than intoxicating effects, according to the +following account by Langsdorf, as translated by Greville. This variety of +Amanita muscaria, is used by the inhabitants of the north-eastern parts of +Asia in the same manner as wine, brandy, arrack, opium, &c. is by other +nations."--"The most singular effect of the amanita is the influence it +possesses over the urine. It is said, that from time immemorial, the +inhabitants have known that the fungus imparts an intoxicating quality to +that secretion, which _continues for a considerable time after taking it_. +For instance, a man moderately intoxicated to-day, will by the next morning +have slept himself sober, but (as is the custom) by taking a teacup of his +urine, he will be _more powerfully intoxicated_ than he was the preceding +day. It is, therefore, not uncommon for confirmed drunkards to preserve +their urine, as a precious liquor against a scarcity of the fungus. The +intoxicating property of the urine _is capable of_ {168} _being +propagated_; for every one who partakes of it has his urine similarly +affected. Thus with a very few amanitae, a party of drunkards may keep up +their debauch for a week." + +This property of the amanita, at once places it in a separate category from +all other organic poisons, it has yet to be shewn upon what this +intoxicating fungus depends for its activity. Whether some secretion is +formed in the tissue of the plant, or whether some new arrangement of the +particles of matter or modification of the sporules, is brought about by +entering the system, it is impossible to say. Langsdorf states that the +small deep-coloured specimens of amanita, and thickly covered with warts, +are said to be more powerful than those of a larger size and paler colour. +As the effect is not produced until from one to two hours after swallowing +the bolus, and as a pleasant intoxication may be obtained by this agent for +a whole day, and from one dose only, there is a defined line between this +and the ordinary narcotics and stimulants in common use. That the digestive +powers of the stomach have no influence over the intoxicating properties of +the plant, is manifested in the fact, that the active principle passes into +the urine, not only not deteriorated but apparently increased, for, as we +have seen, a teacup of the urine from a man, intoxicated by taking the +amanita into his stomach, will cause him to be more powerfully intoxicated +than by the {169} original dose. We have, therefore, but two conjectures +left for consideration, either the original intoxicating principle is +excreted from the system in a condensed form, in which case its +indestructibility by digestion, makes it approach the ordinary organic +poisons, or there must be an increase of the toxic agent, in which case we +must suppose a reproductive process having taken place in the system. +"There is," says Dr. Mitchell, "in the wild regions of our western country, +a disease called the _milk sickness_, the _trembles_, the _tires_, the +_slows_, the _stiff-joints_, the _puking fever_, _&c._" The animals +affected with this disease, "stray irregularly, apparently without motive;" +they lose their power of attention, and finally tremble, stagger, and die. +"When other animals--men, dogs, cats, poultry, crows, buzzards, and hogs, +drink the milk or eat the flesh of a diseased cow, they suffer in a +somewhat similar manner." This disease is attributed by Dr. Mitchell to the +animals having grazed on pasture contaminated with mildew, and the +resemblance to the effects of the amanita, together with the persistence of +the specific principle within the fluids and tissues of the body, render it +more than probable that to some fungoid growth, is due the peculiar toxic +effects here noticed. Further: "The animals made sick by the beef of the +first one, have been in their turn the cause of a like affection in others; +so that three or four have thus fallen victims successively." De Graaf +states, that butter {170} made from the milk of diseased cows, though +heated until it caught fire, did not lose its deleterious properties. The +urine of diseased animals, collected and reduced by evaporation, produced +the characteristic symptoms. All these facts point to some peculiarity in +the properties of matter not yet investigated or at least not explained. If +we may assume that reproduction is here an element of the persistence and +apparent multiplication of active matter, I know only of one instance to +compare with it. A gentleman about to deliver a lecture on the properties +of arsenic, and its history generally, made two solutions of a given +quantity of arsenious acid, in the following manner. He took a certain +amount of distilled water, and the same of filtered Thames water, and made +his solutions of arsenic by separate boilings, he then as soon as possible +placed the liquids in identical bottles, carefully prepared for their +reception. In the one which contained the arsenic boiled in river water, +the hygrocrocis is now growing, while that boiled in distilled water +remains perfectly limpid and free from any vegetable production. There can +scarcely be a doubt, that the filtration of river water was not +sufficiently purifying to remove the minute spores of some lower forms of +vegetation, which not only live in arsenic but have resisted the +temperature employed in boiling an arsenical solution to saturation. + +As to the first class, or truly reproductive and {171} morbid poisons, the +most heterogenous ideas have from all time existed. I have introduced the +notice of the above poisons, viz. the Amanita, and that which engenders the +milk sickness, to compare the results of the morbid poisons on the human +body with them, and also to associate them with the effects of diseased +grain. From the Amanita and that other fungoid matter which is said to +produce the milk sickness, there appears to be a purely toxic action on the +system, but in the instance of diseased grain, a blood disease, ending in +gangrene, or a specific and peculiar action of the generative organs is the +consequence, and where the latter occurs, the poison usually expends itself +on these parts, either by inducing abortion, or augmenting the catamenial +secretion. + +Now, the morbid poisons, if studied only in their results, shew that there +is a combination of these two actions. There is usually, in the first +place, a toxic or poisonous action, and secondly, a deteriorating or +decomposing action on the blood, by which there is a tendency to low or +asthenic inflammation and gangrene. It matters not what form of fever we +take as an illustration, whether intermittent, pestilential, or +exanthematous, either will serve the purpose of shewing how completely the +effects of vegetable organic poisons resemble those which for the sake of +distinction (I suppose) have been denominated Morbid Poisons. + +Take an attack from the paludal poison. It is {172} usually ushered in with +head-ache, weariness, pains in the limbs, and thirst, with other symptoms; +all these are indicative of a poisonous agent in the blood: then come the +full phenomena of the disease at a longer or shorter interval, and tending +ultimately to destroy some organ of the body. The mind suffers during the +course of the attack, and delirium occasionally happens. In severe cases of +this disease, which were more frequent formerly than now, coma, delirium, +and frenzy were observed at the commencement of the attack, and a tendency +to rapid disorganization of one or several of the viscera. + +If we take the effects of poison of Erysipelas, of Scarlet Fever, or +Plague, in each we find at the onset more or less general derangement of +the system, usually with cerebral disturbance and disordered action of all +the dynamic forces of the body, which clearly indicate the action of a +poison; then, unless some favourable symptoms arise, the blood exhibits a +steady advance towards disorganization, and sphacelation of one or more +tissues or parts of the body ensues. In Erysipelas the force of the +diseased action is expended on the skin, and subcutaneous cellular tissue; +in Scarlet Fever the fauces ulcerate, and slough and the parotids +suppurate; in the Plague there is a general tendency to putrefaction, and +the formation of glandular abscesses with sphacelas. Without going any +further into this matter, for my present intention is merely to draw {173} +notice to certain facts, let me now ask, whether or not, do the poisons of +the Ergot, the Uredo, and the Amanita, exhibit more analogy in their action +on the nervous system, the blood and the tissues, than any other poisonous +agents with which we are acquainted? If the whole range of the lower fungi +could be examined in reference to their operation on the blood, as +decomposers of organic compounds,--if experiments could be made, by which +the properties of fungoid matter could be detected, I would venture to say +the whole of the phenomena of these diseases could be readily comprehended +and their intricacies unravelled. + +We know that the fungi are poisonous, that at times and seasons, and under +variations of climate, they vary in their effects, and perhaps lose +altogether these properties. We know that the fungi produce gangrene of the +tissues, and disorganization of the blood; we know that their spores +pervade the atmosphere, and are ready, under favouring conditions, to +increase and multiply; we know that they are ubiquitous, and that those +conditions most favourable to their development, are exactly such as are +proved to foster and engender disease, and above all, they have been proved +to be the elements of some diseases in man, in animals, and in plants. Can +as much be said of any other known agents, animate or inanimate, comprised +in our category? + +It has been said, we do not see after death,--the {174} interlacing +mycilium, or the sprouting pileus; therefore the fungi are not the agents +of disease--it has been said that carbonic acid and alcohol are not found +as products of diseased action--consequently disease is not a fermentative +process. "In all cases," says Liebig, "where the strictest investigation +has failed to demonstrate the presence of organic beings in the contagion +of a miasm, or contagious disease, the hypothesis that such beings have +cooperated, or do cooperate in the morbid process, must be rejected as +totally void of foundation and support." Much as I admire the genius of +this great man, it is difficult to refrain from remarking, that I doubt if +any of his great discoveries would have been made, if, in the first +instance, hypotheses had not formed the basis of all his researches. It has +been said, "that casual conjunctions in chemistry, gave us most of our +valuable discoveries:" and it is from casual conjunctions that hypotheses +are usually formed, the working out proves either their fallacy or their +truth, but to say that an hypothesis has no foundation, until demonstrated +to be true, is rather knocking down argument. And who, let me ask, has been +more prolific of hypotheses than our continental neighbour? Yet he, +according to his mode of reasoning, would sweep away all such words from +the vocabularies of philosophers. What foundation has the chemical +hypothesis of disease, when it fails to explain the most important element +{175} of contagious and infectious diseases: viz. the reproductive property +of their germs? + +It is perhaps necessary to say something in explanation of the sudden +deaths arising from morbid poisons. They may occur from two causes. One +being the result of a concentrated amount of poison germs being inhaled +into the lungs, and acting as an ordinary toxic agent; and the other, which +I put only hypothetically, the consequence of the rapid evolution of gas in +the vessels arising from a sudden decomposition of blood, as it passes +through the lungs. The only authority I have for this supposition, is the +fact that the blood after death, from pestilential affections, is found to +be far advanced towards decomposition; that in Paris last year, two +patients were bled while suffering from Cholera, and with the small +quantity of blood which flowed, bubbles of air also escaped:[70] and +besides this, it was demonstrated by Mr. Herapath, that ammonia was given +off from Cholera patients, both by the lungs and skin. These facts, though +they are not conclusive, nevertheless render it probable that such an +explanation is not entirely out of reason--especially too, when we know how +fatal are the effects of uncombined air, when it enters the vessels near to +the heart. + + * * * * * + +{176} + +SECTION III. + +WHAT RESULTS DO WE OBTAIN FROM THE EFFECTS OF REMEDIAL AGENTS, IN PROOF OF +THE HYPOTHESIS? + +I have here used the word hypothesis, because, having so far advanced in +the enquiry, I trust sufficient has been said to render the term +applicable. + +Under the term remedial agents, I shall include all those causes, whether +natural or artificial, which tend to neutralize or destroy the germs of +infection, or miasmatic poison, whether this be effected out of or within +the body. + +First, then, let us consider the results of drainage and cultivation in +removing the causes of endemic disease. One well authenticated case is as +good as a thousand. I will take one, which, from its source, will be +received as unexceptionable; and from its association with a very learned +and amusing book, will be accepted as an agreeable reminder of the many +pleasant hours spent in the perusal of the poet Southey's "Doctor." + +"Doncaster is built upon a peninsula, or ridge of land, about a mile +across, having a gentle slope from east to west, and bounded on the west by +the river; this ridge is composed of three strata; to wit, of the alluvial +soil deposited by the river in former {177} ages, and of limestone on the +north and west; and of sandstone to the south and east. To the south of +this neck of land, lies a tract called Potteric Carr, which is much below +the level of the river, and was a morass, or range of fens when our Doctor +first took up his abode in Doncaster. This tract extends about four miles +in length, and nearly three in breadth, and the security which it afforded +against an attack on that side, while the river protected the peninsula by +its semicircular bend on the other, was evidently one reason why the Romans +fixed upon the site of Doncaster for a station. In Brockett's Glossary of +North Country words, Carr is interpreted to mean 'flat marshy land,' 'a +pool or lake;' but the etymology of the word is yet to be discovered. + +"These fens were drained and enclosed pursuant to an Act of Parliament, +which was obtained for that purpose in the year 1766. Three principal +drains were then cut, fourteen feet wide, and about four miles long, into +which the water was conducted from every part of the Carr southward, to the +little river Torne, at Rossington Bridge, whence it flows into the Trent. +Before these drainings, the ground was liable to frequent inundations; and +about the centre there was a decoy for wild ducks; there is still a deep +water there of considerable extent, in which very large pike and eels are +found. The soil, which was so boggy at first that horses were lost in +attempting to drink at the drains, has been brought {178} into good +cultivation, (as all such ground may be) to the great improvement of the +district; for till this improvement was effected, _intermittent fevers and +sore throats were prevalent there, and they have ceased from the time the +land was drained_. The most unhealthy season now, is the spring, when cold +winds, from the north and north-east, usually prevail during some six +weeks; at other times Doncaster is considered to be a healthy place. It has +been observed that when endemic(?) diseases arrive there, they uniformly +come from the south; and that the state of the weather may be foretold from +a knowledge of what it has been at a given time in London, making an +allowance of about three days, for the chance of winds. Here, as in all +places which lie upon a great and frequented road, the transmission of +disease has been greatly facilitated by the increase of travelling." + +I feel certain of being excused for transcribing this long passage from +Southey. It would have been impossible to convey its whole meaning without +giving it entire. The continuation of the chapter is no less instructive +and applicable to our subject, though more particularly so to an extension +of the enquiry. The sore throats and intermittents, from which Doncaster +has been freed, by the drainage of Potteric Carr, informs us at once that +decomposing matter is the material by which the poison of fever is vivified +and sustained, the wet and boggy state of the soil is just the condition, +when no drainage exists, to bring into activity the germs of {179} disease, +which otherwise would lie latent. So satisfied and acquainted are we with +the elements necessary for the production of fever, that we might as +certainly bring about an endemic intermittent by forming an artificial bog, +as we could be sure of growing mushrooms by making a bed in the manner laid +down by gardeners for this purpose. Dr. Lindley also says, "the _Polyporus +fomentarius_ has been artificially produced in Germany, but merely by +placing wood in a favourable situation, and keeping it well moistened. Five +or six crops were obtained in the year." + +Let warmth, moisture, darkness, and decaying matter be given, and inanimate +disintegrated particles will soon be converted into definite forms and +combinations instinct with life. It is by the unseen forms of living +beings, that the atmosphere is preserved from becoming charged with deadly +gases; they take the first rank in the great scheme of animated beings, the +plant first, and then the animal. "Let the earth bring forth grass." "Let +there be lights in the firmament." "Let the waters bring forth the moving +creature, and fowl that may fly," and "Let the earth bring forth the +cattle, the creeping thing, and the beast." This is the order of creation, +of living things, and the earth was prepared by vegetation for the animal +world. The work of conversion is accomplished by vegetation; and this is +consumed for the construction of higher organizations. + +The laws which govern and control the universe, {180} are as definite and +as wonderful among invisible atoms, as those which regulate the enormous +masses floating in space; and the time will come when the advancing +intellect of man will measure and weigh the morbid poisons, as he measures +and weighs the stars. Why should the laws of Epidemics be less understood, +than the laws which govern the course of comets? The aspirations of man +have led him to penetrate the heavens, which charm and inspire him; he +studies rather the more violent disturbing elements of nature, the +thunder-cloud and the fire of heaven, than the silent pestilence which +steals over the earth. I cannot conceive it possible that the Intellects, +which are occupied in procuring means for the Majesty of this empire to +issue her mandates with the velocity of a spirit to the nethermost parts of +the earth, should be incapable of solving so deeply interesting a mystery +as the causes and nature of pestilential diseases. It would seem that man +prefers to issue a mandate of destruction many thousand miles distant, than +to disarm the pestilence at his door. It is barely a century since Galvani +observed the twitchings in the muscles of a frog's leg, and the battery, +still named after him, has already become an agent of instantaneous +communication between places many miles distant. But how many centuries +have passed away, each one succeeding the other, with its millions of +victims to epidemics? And where are the remedies for the evils? Drainage +and cleanliness, with all their advantages, were better understood and more +fully carried out by the ancient {181} Romans than by ourselves; there are +monuments, though crumbling to decay, to tell us of the vast enterprise of +these people and of the value they set upon a healthy and vigorous +constitution, and how well they understood the means of warding of disease. + +Cultivation and drainage are now fully understood to be the basis by which +a healthy condition of air is to be obtained, next to that, cleanliness and +ventilation; if either be neglected a sickly, mouldy, and unwholesome +contamination of atmosphere ensues; the odour of a bog is proverbially +mouldy, and so is that of an ill-ventilated house or cellar; dryness, or +the fresh pleasant scent of clean water, are the antagonists of these; the +aromatic odours of vegetation are opponents of putrefaction, and +consequently of the development of the lower forms of life. All +empyreumatic matters prevent mouldiness and decomposition; and odours +arrest and prevent the growth of mouldiness. The oil of birch, with which +the Russia leather is impregnated, and which gives it so pleasant an odour, +effectually prevents mouldiness, and consequently decay. + +Lindley says, "It is a most remarkable circumstance, and one which +_deserves particular enquiry_, that the growth of the _minute fungi_, which +constitute what is called mouldiness, is _effectually prevented_ by any +kind of perfume."[71] Cedar has {182} been used, from time immemorial, for +a like purpose; and I doubt not the recommendation of Virgil, before +quoted, in reference to the burning of cedar, was founded on some practical +utility of this kind, though its _modus operandi_ was unknown to him. +Allied to these is a curious circumstance, and worthy attention. I copy the +following from an old work on Pestilences. "It is remarkable that when the +Plague raged in London, Bucklersbury, which stood in the very heart of the +city, was free from that distemper; the reason given for it is, that it was +chiefly inhabited by druggists and apothecaries, the scent of whose drugs +kept away the infection, which were so unnatural to the pestilential +insects, that they were killed or driven away by the strong smell of some +sorts of them." "The smell of _rue_, and the smoke of tobacco, were +prescribed as remedies against the infection; but especially tar and pitch +barrels, which it was imagined preserved Limehouse, and some of the +dock-yards from infection."[72] + +Pitch and tar dealers are everywhere spoken of as being remarkably exempt +from infectious diseases. + +Cold infusion of tar was used in our colonies as a prophylactic against the +Small Pox. Bishop {183} Berkeley was induced to try it when this disease +raged in his neighbourhood. The trial fully answered expectation--for all +those who took tar-water, either escaped the disease, or had it very +slightly. + +Tan yards and places in the immediate vicinity, are said to be free from +pestilences. The tanners of Bermondsey are said to have escaped the Plague +of London, and one person only died in Gutter Lane, where was a tan yard. +The tanners of Rome are also stated to have been free from Plague. Dr. +McLean refers to the exemption of tanners at Cairo. _Tannin is prejudicial +to most vegetables_,--but Dr. Lindley says it is not always so to fungi. "A +species of Rhizomorpha is often developed in tan pits." I should imagine +that neither plants nor insects would be found very abundantly, where +tannin prevails; yet we find that the gall-nut is formed for the protection +of an insect from injury by weather, and as a temporary means of +sustenance. + +The custom of fumigating with odoriferous substances, does not therefore +appear upon this view of the matter to be destitute of importance; indeed, +the universal practice stamps it at once, as an efficacious remedy for the +purposes of disinfection. The introduction of chlorine fumigation, seems to +have superseded, in a great measure, the use of fragrant herbs and woods; +and it is questionable whether the substitution be altogether desirable or +{184} advantageous. Many scents may be agreeably and usefully employed, +with much less chance of annoyance to the patient, and considerably less +injury to articles of furniture, &c. + +The fumigations of sulphurous acid and chlorine are, perhaps, more adapted +as disinfectants in uninhabited apartments;--their power to destroy +vegetation, is well known. They have been used, chiefly, with the idea of +neutralizing gaseous exhalations, particularly chlorine, as it tends to +combine with hydrogen, to form hydrochloric acid, and then to unite with +ammoniacal matters, forming hydrochlorate of ammonia. This, supposing +noxious or pestilential effluvia consisted of the ammoniacal exudations +variously combined, was an exceedingly efficacious method of rendering them +inert; but as we feel convinced that no ammoniacal compound could possibly +be the cause of infection, we must look to the influence these gases +possess over other forms of matter, and as they are so destructive, even in +minute quantities, to vegetable existence, it is possible that their +beneficial effects may be due to this property. The immediate neighbourhood +of gas works is prejudicial to vegetation, I imagine, from the amount of +sulphurous vapours, and to this has been attributed the exemption of +persons employed in these works. Many other instances might be cited of a +similar nature. + +I have now to speak of medicinal agents, and here comes a considerable +difficulty. {185} + +If we might believe all that has been written on the sure and certain +remedies for the "ills that man is heir to," we should be led to +acknowledge that both nature and art were prodigal in antidotes and +specifics. The all-bountiful hand of nature, I do not doubt, has at the +same time scattered the seeds of good and of evil. The fertilizing showers +fall to irrigate the soil, and produce food and nourishment to man; here +and there is the reeking morass "feeding unnatural vegetation," and if man +takes up his abode in its vicinity, the rains which made it unhealthy, have +also made it highly fertile; by labour and cultivation he may convert the +mephitic bog into a waving corn-field, and the seeds of life and sustenance +be made to supplant the seeds of death and corruption. + +It is generally believed, that where there are particular and specific +diseases, there also may be found appropriate and specific remedies; the +discoveries of chemistry, it is not improbable, may in some respects have +retarded the progress of natural medicine. In the early ages of the world, +the "healing plant" must have formed the staple of medical commerce, for +though Tubal Cain[73] has been considered as the first surgical instrument +maker, because he was the first artificer in brass and iron, we have not +discovered that chemical compounds entered into the composition of physic, +till very {186} many years after his time. To the alchemists we owe the +science of chemistry, and much of the physic of the present day may be +traced to them. The multiplicity of ingredients which at one time entered +into the composition of one dose of physic could only be spoken of under +the title of "legion." Who shall specify the active and curative ingredient +(if there be one), when from five to a hundred may have been exhibited at +the same time? It has been the pride of our physicians, that the +pharmacopoeia has been simplified; it has not reached its most simple form +yet. That many simple plants have specific and wonderful power over +disease, is an indubitable fact, but I firmly believe that the laudable, +though mistaken efforts of physicians to improve their effect by various +combinations, have been the means of throwing many valuable medicines into +oblivion; I must also add, that cheap physic and adulterations have had no +small share too in the banishment of much valuable physic from ordinary +practice. It has been believed, and I think with much reason, that a +thorough search into the qualities of plants, would shew that "they are +capable of affording not only great relief, but also effectual and specific +remedies." "That they are not already found, is rather an argument that we +have not been sufficiently inquisitive, than that there are no such plants +endued with these virtues." + +Of the result obtained by medical treatment, in cases of epidemic or +infectious disease, it is most {187} difficult to speak, but as my province +here is only to shew that living germs are the morbific agents, I have but +to refer to such remedies as have been most extolled in controlling these +affections. The disinfectants have already been mentioned in a cursory +manner. An enumeration only of simple medicines used during the late +Epidemic, shall conclude this work, as the treatment in former times could +not by any possibility furnish satisfactory information. Aromatics and +fragrant stimulants have in all times taken the foremost rank with acids, +such as vinegar, lime and lemon juice. Mr. Guthrie's adoption of lemon +juice in preference to bark, which he said made him worse while suffering +from an attack of fever, during the Peninsular campaign, and his speedy +recovery from the disease, though not from its effects, shews, when many +others can bear equal testimony to its value, that such a remedy though +simple is not to be despised. + +But to the late Epidemic. Dr. Stevens' saline treatment, appears, on the +whole, to have been the most successful. Common salt was used both +medically and dietetically, and formed the greatest bulk of the medicine +employed. Chlorate of potash and carbonate of soda were added to the +medicine. + +The nitro-hydrochloric acid was used with success at St. Thomas's Hospital. + +Dr. Copland used chlorate of potash, bicarb. soda, hydrochloric, ether, and +camphor water. + +Dr. Ayre's calomel treatment had as many, if {188} not more, opponents than +advocates. Phosphorus had several advocates. + +Creasote and camphor were lauded by some. The beneficial operation of all +these remedies might be explained on the theory here supposed, that living +germs are the cause of Epidemic disease, but the specific action of any one +remedy has not yet had sufficient attention or trial to enable me to make +any deductions of a satisfactory or conclusive nature. + +In the uncertainty which generally prevailed as to the best method of +treating Cholera patients, I was induced (for reasons stated in a pamphlet +published last year) to try the efficacy of sulphur, which had been +extolled as a specific. In its effects I was not disappointed; but as the +results are already before the public, I need not do more than refer to it +among other remedies. + +I did not contemplate even alluding to this subject, as it would extend far +beyond my intended limits. This portion of the enquiry would be more +properly carried out by keeping records of cases, treated in accordance +with the view attempted to be established, and I have not the slightest +hesitation in saying, that the most ample success would ultimately attend a +well directed practice, based upon the principles inculcated in these +pages. + + * * * * * + + +{189} + +CONCLUSION. + +In making the foregoing sketch, I have attempted to put together some ideas +on a subject, which has for the last few years been a theme for meditation +in leisure hours, viz. What are the causes of Epidemic, Endemic, and +Infectious Diseases? The occurrence of Epidemic Cholera last year in this +country, awakened a spirit of enquiry. Where there is unrest, whatever may +be the cause, there also is disquiet and discontent. When the oracles of +the age were consulted in the emergency, the discordant answers perplexed +and confused the anxious searcher after truth. In the spring of last year, +when the enemy was approaching, unseen and unheard, and the thousands of +unconscious victims, who are now lying in their graves, were faithfully +trusting and fully relying on the heads of our profession, and the +resources of our art, what was the state of our defences, and what the +nature or character of our resistance? One considerable body of men would +discharge from a little tube of glass, a host of almost invisible globular +atoms of sugar, said to be as potent and inscrutably operative as the +unseen enemy. These infinitesimal practitioners assured the people that +they "_had powerful means of subduing the disease_," {190} but even they +differed among themselves, though they carried out to the fullest extent +the doctrine of their leader, _similia similibus_, which we may suppose to +refer in this case to the minuteness of the opposing armamenta. Without, +however, agreeing with this school, I may quote a passage from Dr. Curie, +which is, alas! too true: "We have shewn, as they must (allopathists), and +many of them do acknowledge, that they have no fixed basis, no natural law +upon which their treatment rests." + +Who can deny the force of this observation? Sheltered by a principle, it +matters not how fallacious, a man is placed as behind a barrier. If with +any reason it could be shewn that the infinitesimal doses, could by no +possibility effect a cure in Cholera; if it could be demonstrated by any +line of argument, that a poison, a living poison, circulates with the +blood, or lodges in the tissues, the homaeopathist must fall; his +"electricity and mineral magnetism," and "_powerful concentration of life +power towards the digestive canal_," will stand for what they are worth. +That minute doses of medicine can exert an active influence over the body +is not to be denied, but these must consist of powerful drugs, as arnica, +aconite, and nux vomica, with others, and it is more than probable, that of +such medicines, an inconceivably small amount may produce a specific effect +upon some portion of the organic nervous system. + +How is it that a dose of nitre or digitalis, "can {191} convert +cheerfulness into low spirits," or a grain of red sulphuret of antimony, +"excite warmth and lively spirits?"[74] + +Why should indigo dyers become melancholy, and scarlet dyers choleric?[75] +We do not know. But there is one thing we most certainly do know, that a +poison may be disarmed by an antidote, and the amount of the latter must be +in proportion to that of the former, and as epidemic and contagious +diseases do most unquestionably depend upon poisons of a specific nature, +and of great amount and activity, an infinitesimal remedy, however it may +claim to direct and control the organic forces, under slight and ordinary +disturbances, can be no more effectual in destroying the poison of fever, +or small pox, than in neutralizing arsenic or prussic acid. + +The uncertainty which generally prevails as to the treatment of Epidemic +diseases, Fevers, &c. induced me to put together the notions which are +contained in these pages, in the hope of leading to some definite ideas of +the causes of these affections, and consequently to a more uniform and +scientific mode of treating them. + +I have endeavoured to shew that reproduction is a phenomenon inseparable +from morbific matter, and that in all probability the vegetable kingdom is +the source of the germs. + +{192} + +The train of argument adopted is such as appeared to me most natural for +such an enquiry, and it rests now only with those who are capable of +deciding whether such a course, though (I am sensibly aware) not without +many faults in conception and execution, is calculated to advance the +science of medicine and the interests of mankind. + +The real tree of knowledge, possesses in the spongioles of its roots, an +elective property, by which truth alone can enter; nourished and sustained +by this, it sends a fragrant incense and breathing odour on high, and +dispels the mists of ignorance and superstition. In natural causes and +reasonable deductions we must seek for instruction and solid information, +for in over-straining either nature or art, deformity and error must +inevitably be the result. + +THE END. + +NORMAN AND SKEEN, PRINTERS, MAIDEN LANE, COVENT GARDEN. + + * * * * * + + +NOTES + +[1] "It matters little how vague and false hypotheses may appear at first: +experiment will gradually reduce and correct them, and all that is +required, is industry to elaborate the proof, and impartiality to secure it +from distortion."--_Sewell_ "On the Cultivation of the Intellect." + +[2] It is stated by Mr. Crosse, of Norwich, that vaccination was adopted in +Denmark, and made compulsory in 1800. After the year 1808 Small Pox no +longer existed there, and was a thing totally unknown; whereas during the +twelve years preceding the introduction of the preventive disease, 5,500 +persons died of the Small Pox in Copenhagen alone.--_Dr. Watson's +Lectures._ + +Dr. Blick, an intelligent Danish physician, corroborated the above +statement to Dr. Watson himself in the year 1838. + +[3] Philosophy of Life, Lecture 6, translated by the Rev. A. J. W. +Morrison, M.A. + +[4] The following I quote from Dr. Fuller on Small Pox and Measles:-- + +"To this purpose some (and particularly Kircherus) are of opinion that +animalcules have been the causes of malignant and pestilential fevers in +epidemic times, which differ in essence and symptoms, according to the +nature and venoms of those creatures. + +"Thus the atmosphere and air is filled both from above and beneath with +innumerable millions of millions of species or corpuscles, aporrhoeas, +steams, vapours, fumes, dust, little insects, &c. all which make it such a +wonderful chaotic compost of things that contains the _seeds_ of good and +evil to man as surpasseth the understanding (as I suppose) of even the +highest order of archangels." + +[5] I learn from an undoubted authority that the cow when "slack of health" +eats with avidity the "field parsley;" the sheep under similar +circumstances seeks the ivy, and the goat the plantain. + +From an equally good source I have the following: that rabbits and hares, +when they are what is commonly called _pot-gutted_, seek the green broom, +though at a distance of _twenty miles_. + +[6] "My settled opinion is, that in regard every effect is necessarily such +as its cause; it must needs be that every sort of venomous fevers is +produced by its proper and peculiar species of virus. + +"And that the manner and symptoms of every such fever is not so much from +the particular constitution of the sick; as from the different nature and +genius of their specific venom which caused them. + +"And I conceive that venomous febrile matters differ not in degree of +intenseness only, but in essence and _toto genere_ also; and that venomous +fevers are for the most part contagious."--_Thomas Fuller, M. D. 1730._ +"Another important class of organic poisons are those which when introduced +in almost inappreciable quantities into the system, seem to increase in +quantity; and which when communicated in the same inappreciable quantity +from the individual poisoned to one who is healthy, excite the same series +of febrile phenomena and local inflammation, and the same increase in the +quantity of the poisonous agent."--_Med. Chir. Review._ + +"This unseen influence working in the body, presents very striking +analogies to the modes of operation of different poisons."--_Dr. Ormerod on +Continued Fever._ + +[7] I am aware that the vesicle does not here strictly bear the relation to +the original germ, supposing one active particle alone to be sufficient for +its production, that the egg does to the bird, for in the former case +multitudes of active particles may have been generated from one. I have, +therefore, merely used this expression to signify an aggregation of vital +forces, such as may be imagined to exist in the bird. + +[8] "At an early period the form of the ovisacs is usually elliptical, and +their size extremely minute,--their long diameter measuring in the ox no +more than 1/562 of an inch, so that a cubic inch would contain nearly two +hundred millions of them. They are _at this time_ quite distinct from the +_stroma_ of the ovarium; this forms a cavity in which they are loosely +embedded." + +[9] Coleridge, p. 56. + +[10] "All vegetables," says Sharon Turner, "from that pettiness which +escapes our natural sight, to that magnitude which we feel to be gigantic, +have these properties in common with all animals--organization; an interior +power of progressive growth, a principle of life, with many phenomena that +resemble irritability, excitability, and susceptibility, and a +self-reproductive and multiplying faculty."--_Sharon Turner's Sacred +History._ + +[11] "Plants highly sensitive to light are those of the leguminous, or Pea +kind. They always close up in the evening and clasp their two upper +surfaces together, presenting only their backs to the air. Plants of +pinnated leaves, as the Tansy, are more sensible than these to the effects +of light. They fold up when light is too strong, as in Robinia; it produces +the same effect as want of light. Its leaves close up, apparently, because +they are receiving too much. So they do if a hot iron be brought near them. +They contract as if to avoid the heat. Sensitive plants, and those of the +Oxalis Lent. are so sensitive that the least motion, even a breath of air, +will make them close."--_Sir J. Smith._ + +"The vitality of plants seems to depend upon the existence of an +irritability, which although far inferior to that of animals, is +nevertheless of an analogous character."--_Lindley's Introduction to +Botany._ + +[12] Provincial Medical and Surgical Journal. July 10th, 1850. No. xiv. p. +367. "Practical Observations on the Vaccination Question." By E. Oke +Spooner, M. R. C. S., Blandford. + +"If we examine the Cow Pox and the Small Pox microscopically, as I have +done very carefully in every stage, we find that the essential character +consists of a number of minute cells, not exceeding the 10,000th part of an +inch in diameter, being about one-fourth smaller than the globules of the +blood, containing _within their circumference many still more minute +nuclei, and presenting_ beyond their circumference bud-like cells of the +same size and character as those contained within the circle. They exactly +resemble in everything except the size, the globules of the yeast plant, +the Torula Cerevesiae. Now if we examine more circumstantially the +analogies of what I would call the Torula Variolae with the Torula +Cerevesiae, we observe the following corresponding facts. + +"What do we accomplish by inoculation as it is called? Simply this. We take +on the top of a lancet, or an ivory point, a few of these minute cells or +germs, and we put them _in their appropriate nidus_, the subcuticular +tissue, where, after a few days if they find their appropriate nutrient +elements, they grow and multiply." + +Simon, Chemistry of Man, vol. i. p. 127. "Macgregor ascertained that the +air expired by persons ill of confluent Small Pox, contained as much as +_eight_ per cent of carbonic acid, and in proportion as health was restored +the percentage was diminished to its natural standard." Carbonic acid is +also produced during the process of fermentation and germination. + +[13] See History of the Jews, p. 71. + +[14] It is said by Whewell, that the murrain is supposed to have fallen +only on the animals which were in the open pasture.--_History of the Jews._ + +"J. S. Michael Leger, published at Vienna, in 1775, a treatise concerning +the mildew as the principal cause of the epidemic disease among cattle. The +mildew is that which _burns_ and _dries_ the grass and leaves. It is +observed early in the morning, particularly after _thunder-storms_. Its +poisonous quality, which does not last above twenty-four hours, never +operates but when it is swallowed immediately after its +falling."--_Mitchell on Fevers._ + +[15] "The prevalence of the south-east wind was observed to be particularly +favourable to the increase of both cholera and influenza: and I cannot but +think that this had some connexion with the general tendency exhibited by +the former to spread from east to west. Has the morbific property of this +wind aught to do with the haziness of the air when it prevails--a haziness +seen in the country remote from smoke, and quite distinct from fog? What is +this haze? In the west of England a hazy day in spring is called a +_blight_."--_Dr. Williams' Principles of Medicine._ + +[16] We are to understand also that some peculiar operation took place of a +nature difficult to comprehend, which seems also to typify reproduction, +for the handfuls of ashes which Moses threw into the air _became a dust in +all the land of Egypt_, thus signifying an enormous reproduction of atomic +matter. + +[17] The Chinese affect to trace the origin of Small Pox back to a period +of at least 3000 years, or 20 years beyond the era of the Trojan war, 1212, +A. C. + +The Chinese pretend to discriminate no less than 40 different species of +Small Pox. + +"They also pretend to discover whether a person has died by violence or +from natural causes, not only after the body has been some time interred +and decomposition of the softer parts has commenced, but even after the +total disappearance of the soft parts, and when the dry skeleton alone is +left."--For the process, see _Hamilton's History of Medicine_, vol. i. p. +31. + +To give some notion of the state of Medical Science among the Chinese, I +may quote the following: "The theory of the circulation of the blood, Du +Halde affirms, was known by the Chinese about 400 years after the deluge; +be this assertion veracious or not, no correct knowledge up to the present +day, do the nation possess of the circulating system of the human +frame."--_China and the Chinese, Henry Charles Sirr, M. A._ + +According to their anatomy, the trachea extends from the larynx through the +lungs to the heart, whilst the oesophagus goes over them to the stomach. + +[18] "And Aaron took as Moses commanded, and ran into the midst of the +congregation: and behold the plague was begun among the people; and he put +on incense and made an atonement for the people. And he stood between the +dead and the living, and the plague was stayed."--_Numbers._ + +The practice of burning scented herbs has been observed in all times during +an invasion of the plague, as a means of protection. Also wearing perfumes +and aromatic preparations has been recommended. Whether they have any +counteracting influence, it is impossible to say. + +Virgil in the third Georgic speaks of a murrain among cattle. He says, if +any wore a vestment made of wool from an infected sheep, fiery blains and +filthy sweat overspread his body, and ere long a pestilential fire preyed +upon his infected limbs. + +In his directions for preserving the health of flocks he says-- + + "Disce et odoratam stabulis accendere cedrum." + +The motive for burning the fragrant cedar is not mentioned; we cannot doubt +but it was a good one, and having some great practical utility, from the +following line-- + + "Galbaneoque agitare graves nidore chelydros." + +[19] The earliest mention of this complaint upon which reliance can be +placed, is an ancient Arabic MS. preserved in the public library at Leyden. +"This year, in fine, the Small Pox and Measles made their first appearance +in Arabia." The year alluded to being that of the birth of Mahomet, or the +year 572 of the Christian aera.--_Hamilton's History of Medicine_, vol. i. +p. 215. + +[20] Dr. W. A. Greenhill's translation. + +[21] The Black Assize at Oxford, 1572, is an instance in which a +pestilential vapour suddenly appeared in the court, "whereby the judge, +several noblemen, and more than 300 others, died within three days." + +"Of an unaccountable vapour suddenly coming, I have this relation from +Richard Humphrey, my neighbour, and a man of veracity, that on Wednesday, +April 27, 1727, as he and one Walter, were travelling a-foot from +Canterbury; when they came to Rainham, they were assaulted with such a +strong loathsome stink, as he thought was like the stench from a corrupted +human corpse. They were so offended at it, as thinking it was from carrion +in that town, that they would not stay there to rest and refresh +themselves, but travelled on for about two hours, mostly in the stench, but +sometimes out of it, till they came to the hill that leads down to Chatham: +and there they went clear out of it and smelt it no more."--_Dr. Fuller_. + +It appears that these persons did not fall sick of any disease, but the +fact of itself is remarkable enough. + +[22] Hamilton's History of Medicine. + +[23] It has been said, that "an induction once carefully drawn, is as +perfect from a single instance as it is from ten thousand, and that it is +only an uncultivated mind which requires a load and accumulation of +knowledge to assist his thoughts."--_Sewell_ "on the Cultivation of the +Intellect." + +[24] See Dr. Alison's Pamphlet on the Fever in Edinburgh. + +[25] Earthquakes have in all times been considered to have some connexion +with pestilences. "A most grievous pestilence broke out in Seleucia, which +from thence to Parthia, Greece, and Italy, spread itself through a great +part of the world, from the opening of an ancient vault in the temple of +Apollo, and that it raged with so much fury as to sweep away a third part +of the inhabitants of those countries it visited."--_Dr. Quincy, on the +Causes of Pestilential Disease._ + +"Upon an earthquake the earth sends forth noisome vapours which infect the +air; so it was observed to be at Hull in Yorkshire, by the Rev. Mr. Banks, +of that place, after a small earthquake there in 1703, it was a most sickly +time for a considerable while afterwards, and the greatest mortality that +had been known for fifteen years."--_Anonymous_, 1769. + +[26] See Sharon Turner's Sacred History, text and notes, vol. i. p. 161 & +162. + +[27] + + "Each seed includes a plant; that plant, again, + Has other seeds, which other plants contain, + Those other plants have all their seeds; and those + More plants, again, successively enclose. + Thus ev'ry single berry that we find, + Has really in itself whole forests of its kind. + Empire and wealth one acorn may dispense, + By fleets to sail a thousand ages hence; + Each myrtle-seed includes a thousand groves, + Where future bards may warble forth their loves." + +[28] "On June 5th, 1849, a man and his son, a lad aged 14 years, left Noss +to fish, and when five miles out at sea, no vessel being in sight, they +both simultaneously became aware of a hot _offensive_ stream of air passing +over them. It was so decided, that the crab pots were examined to discover +if it were from them, but it did not, and five minutes after the father's +attention was directed to the boy, who was vomiting and purging."--_Dr. Roe +on the Cholera at Plymouth, Med. Gaz. Aug. 24th, 1850._ + +[29] Linnaeus remarked that Erigeron Canadense was introduced into gardens +near Paris from North America. The seeds had been carried by the wind, and +this plant was in the course of a century spread over all France, Italy, +Sicily and Belgium. + +[30] Hecker. + +[31] This is found most generally to be the case where rivers flow through +uncultivated tracts of country. The Californian emigrants suffer much from +diarrhoea and dysentery, if they drink of the river and certain well waters +of that gold district. + +[32] "Purification from leprosy. As this fearful disease was contagious and +hereditary to the third and fourth generation, the separation of lepers +from the camp and congregation, and the destruction of infected houses and +clothes, was of the utmost importance to the preservation of public health. + +"Leprosy was of three kinds: 1st, Leprosy in man. 2nd, Leprosy in houses. +3rd, Leprosy in clothes. + +"Contagious or malignant leprosy was of two kinds, viz. + +"1st. The white leprosy, or bright berat, which was the most serious and +obstinate form which leprosy assumes. It exhibited itself as a bright white +and spreading scale, on an elevated base; turning the hair white in +patches, which were continually spreading. + +"2nd. The black leprosy, or dusky berat, which was less serious than the +foregoing. It did not change the colour of the hair, nor was there any +depression in the dusky spot; but the patches were perpetually spreading, +as in the white leprosy."--_Analysis and Summary of Old Testament History._ +_Oxford._ + +[33] The Mexican Aloe blows when nine years old, and then dies. At least +this is its usual course in the island of Cuba. + +[34] "Ground that has not been disturbed for some hundred years, on being +ploughed, has frequently surprised the cultivator by the appearance of +plants which he never sowed, and often which were then unknown to the +country. The principle has been ascertained to be capable of existing in +this latent state for above 2000 years, unextinguished, and springing again +into active vegetation, as soon as planted in a congenial soil. + +"In boring for water near Kingston on Thames, some earth was brought up +from a depth of 360 feet, and though carefully covered with a hand-glass to +prevent the possibility of other seeds being deposited on it, was yet in a +short time covered with vegetation. + +"Turner says, from the depth, these seeds must have been of the diluvian +age."--_Jesse's Gleanings._ + +[35] Hamilton's History of Medicine, vol. ii. p. 276, note. + +[36] "What I wish you to remark is this, that while almost all men are +prone to take the disorder, large portions of the world have remained for +centuries entirely exempt from it, until at length it was imported, and +that then it infallibly diffused and established itself in those +parts."--_Dr. Watson on the Principles and Practice of Physic._ + +Dr. R. Williams says, "The seeds of intermittent fever lay dormant for +months, it was not at all uncommon for cases of intermittent fever to be +brought into the hospital eight or ten months after the patients had +subjected themselves to the influence of paludal or marsh effluvia." + +[37] I have observed in the hot-houses, that many of the exotic plants, +which are in company with the diseased vines, have been attacked, while +others again have been entirely free. + +[38] By causes of the greatest variety plants may become extinct for a +time. It is not very easy to trace them, but one fact may be mentioned in +proof of the statement. Dr. Prichard states that vast forests are destroyed +either for the purpose of tillage or accidentally by conflagrations. "The +same trees do not reappear in the same spots, but they have successors, +which seem regularly to take their place. Thus the pine forests of North +America when burnt, afford room to forests of oak trees." + +[39] Hecker says of Chalin de Vinario, that "he asserted boldly and with +truth, that _all epidemic diseases might become contagious, and all fevers +epidemic_,--which attentive observers of all subsequent ages have +confirmed." P. 60. + +[40] In 1539, the thirty-first year of Henry the Eighth, was great death of +burning agues and flixes; and such a drought that welles and small rivers +were dryed up, and many cattle dyed for lacke of water; the salt water +flowed above London Bridge.--_Stowe._ + +In 1556, the fourth of Mary, and the third of Philip, about this time began +the burning fevers, quarterne agues, and other strange diseases, whereof +died many.--_Stowe._ + +The next winter, 1557, the quarterne agues continued in like manner, or +more vehemently than they had done the last yere.--_Stowe._ + +[41] Every writer on the climate of Egypt has remarked, that the Endemic +Fever which is so frequent, originating on the coast, particularly about +Alexandria, becomes occasionally so virulent, that it cannot be +distinguished from the _true Plague._--_Robertson on the Atmosphere_, vol. +2. p. 384. + +"Endemial Fevers of every situation become occasionally so aggravated, that +they cannot be distinguished from such as originate from contagion; and in +every unusual virulence of this Endemic Fever, it is probable that it may +be propagated afterwards by contagion as every epidemic." _Ibid._ p. 388. + +[42] Dr. Ure. + +[43] "The metamorphosis of starch into sugar depends simply, as is proved +by analysis, on the addition of the elements of water. All the carbon of +the starch is found in the sugar; none of its elements have been separated, +and except the elements of water, no foreign element has been added to it +in this transformation."--_Liebig_, _Organic Chemistry_, p. 71. + +[44] As regards starch there appears to be some peculiar faculty regarding +it. It is converted into sugar during the ripening of fruit, and it is just +possible that being as it is of a cellular nature, the property of vitality +may attach to it until it has, by being converted into sugar, fulfilled its +destination. + +[45] Though I do not consider that the fermentation process is a fac-simile +of diseased action, yet I think its phenomena generally afford an apt +illustration of the changes which may be effected by living germs. Many +able chemists still maintain the entire dependence of fermentation upon the +Torula: "M. Blondeau propounds the view that _every kind_ of fermentation +is _caused_ by the development of fungi." + +The varieties of opinions found in the literature of this subject, forms a +curious specimen of scientific enquiry, and is sufficient alone to convince +us of its vast importance and extensive relations. + +[46] By Dr. Mantell. + +[47] Mitchell on Fevers. + +[48] We wonder, and ask ourselves: "What does SMALL mean in +Nature?"--_Schleiden's Lectures on Botany._ + +[49] Speaking of the bunt in wheat: "It appears certainly to be contagious, +from numerous experiments, which shew that the contagious principle lasts a +long time. I have tried it myself; some, however, doubt it, but it cannot +be denied, that seed sown, infected with bunt, produces plants similarly +affected; every one who has had the slightest experience must be convinced +of it."--_Essay on the Diseases of Plants._ _Count R['e]._ + +[50] We have already spoken of the effects of these poisons, and have +stated that the amount of each poison capable of destroying the body is +pretty accurately known. + +[51] The italics are my own. + +[52] Gmelin says: "But the mode of action in these transformations, +sometimes admits of other explanations; and when this is not the case, our +conception of it is by no means sufficiently clear to justify the positive +assumption of this, so called contact-action or catalytic force, which, +after all, merely states the fact without explaining it"--_Gmelin's +Hand-book of Chemistry_, vol. i. p. 115. + +[53] The history and symptoms of some epidemic diseases, such as cholera +and influenza, are not inconsistent with the hypothesis that they are +caused by the sudden development of animalcules from ova in the blood. But +there is a total want of direct observation in support of this +hypothesis.--_Dr. Williams' Principles of Medicine._ + +[54] Since writing the above, I have referred for information on this +subject, and find, that the Anguillula aceti exhibits sexual distinctions; +and that the ovaries of the females are situated on each side of the +alimentary canal.--_Cyclo. Anat. and Phys. Art. Entozoa._ + +[55] Speaking of the examination of the infusory animalcules--Mr. Kirby +says: "But to us the wondrous spectacle is seen, and known only in part; +for those that still escape all our methods of assisting sight, and remain +members of the invisible world, may probably _far exceed those that we +know_."--_Bridgewater Treatise_, vol. i. p. 158. + +[56] Mr. Owen has added another class, as the first, called Protelmintha, +which comprises the cercariadae and vibrionidae. + +[57] "It is probable that in the waters of our globe an infinity of animal +and vegetable molecules are suspended, that are too minute to form the food +of even the lowest and minute animals of the visible creation: and +therefore an infinite host of invisibles was necessary to remove them as +nuisances."--_Bridgewater Treatise_, vol. i. p. 159. + +"When Creative Wisdom covered the earth with plants, and peopled it with +animals, He laid the foundations of the vegetable and animal kingdoms with +such as were most easily convertible into nutriment for the tribes +immediately above them. The first plants, and the first animals, are +scarcely more than animated molecules,* and appear analogues of each other; +and those above them in each kingdom represent jointed +fibrils."+--_Bridgewater Treatise_, vol. i. p. 162. + +* Globulina and Monus. + Oscillatoria and Vibrio. + +[58] "A treatise which should present a systematic arrangement of all the +diseases of plants, giving in detail the exact history of each, and adding +the means of preventing and curing them, would certainly be of the greatest +utility to agriculture." --_Essay on the Diseases of Plants, Count Philippo +R['e], translated into Gardener's Chron._ + +[59] "Plenck published a treatise on Vegetable Pathology, in which he +divided diseases into eight classes: 1. External injuries; 2. Flux of +juices; 3. Debility; 4. Cachexies; 5. Putrefactions; 6. Excrescences; 7. +Monstrosities; and 8. Sterility. And he concludes with an enumeration of +the animals which injure plants."--_Essay on the Diseases of Plants, +Gardener's Chronicle._ + +[60] The Bunt. "This disease appears at the moment of the germination of +the plant. The affected individuals are of a dark green, and the stem is +discoloured. As the ears are issuing from the sheaths, their stalks are of +a dark green, but very slender. When the ear has fully grown out, its dull, +dirty colour, causes it to be immediately distinguished from the healthy +ones, and it soon turns white."--_Essay on the Diseases of Plants._ + +[61] _Vidi_ understood. + +[62] "At the close of the year 1665," says Dr. Hodges, "even women, before +deemed barren, were said to prove prolific." + +"After the cessation of the Black Plague, a greater fecundity in women was +every where remarkable--a grand phenomenon, which from its occurrence after +every destructive pestilence proves to conviction, if any occurrence can do +so, the prevalence of a higher power in the direction of general organic +life. Marriages were almost without exception prolific; and double and +treble births were more frequent than at other times."--_Hecker_, p. 31. + +[63] It is stated that on the decline of the Plague, 1665, those who +returned early to London, or new comers, were certain to be attacked. In +proof of this the 1st week of November, the deaths increased 400, and +"physicians reported that above 3000 fell sick that week, mostly new +comers." + +See also Dr. Copland's Dict. Pract. Med. Epidemic and Endemic Diseases. + +"The hardy mountaineer is a surer victim of paludal fever, whether he +visits the low countries of the tropics, or the marshes of a more temperate +climate, than the feebler native of those countries."--_Dr. R. Williams on +Morbid Poisons._ + +[64] "Substances presented to the gastro-intestinal surfaces, are mixed up +with various secretions, mucus, saliva, gastric juice, bile, pancreatic +liquor, and special exudations from the peculiar glands of each successive +section, while aerial poisons, unmixed and unfettered, are applied at once +to a surface on which, behind scarcely a shadow of a film, circulates the +blood prepared, by the habitual action of the respiratory function, to +absorb almost every vapour, and every odour, which may not be too +irritating to pass the gates of the _glottis_."--_Mitchell on Fevers._ + +[65] Hecker on the "Black Death." + +[66] The stomach in some cases is no doubt the medium by which some +diseases are contracted. It is well known, that in many places the water +induces diarrhoea, the permanent residents, however, may not suffer, but +all new comers are more or less affected by drinking it. + +[67] "Similar effects have been experienced from the use of mouldy +provisions."--_Dr. Lindley's Vegetable Kingdom._ + +[68] "Untold numbers die of the diseases produced by scanty and +_unwholesome food_."--_Southey._ + +A large, nay, a most extensive adulteration of flour with plaster of Paris +was detected not many years since. The flour was supplied by a contractor +for the manufacture of biscuits for the navy. + +[69] See Southey's Doctor, vol. ii. interchapter vi. p. 115, for an +illustration of this subject. + +[70] Both these patients died. + +[71] "A good part of the clove trees which grew so plentifully in the +island of Ternate, being felled at the solicitation of the Dutch, in order +to heighten the price of that fruit, such a change ensued in the air, _as +shewed the salutary effect of the effluvia of clove trees and their +blossoms; the whole island, soon after they were cut down, becoming +exceeding sickly_." + +[72] The observation is originally taken from the City Remembrancer, 133. + +[73] See Hamilton's History of Medicine, vol. i. p. 4. + +[74] Feuchtersleben's Medical Psychology, p. 176, 177. + +[75] Ibid. p. 321. + + * * * * * + + +CHANGES MADE AGAINST PRINTED ORIGINAL. + +Page 136. "the idea of Protophyta, or first plants": 'Prolophyta' in +original. + +Page 140. "an extensive bearing of each individual part": 'indivdual' in +original. + + + + + + +End of the Project Gutenberg EBook of Epidemics Examined and Explained: or, +Living Germs Proved by Analogy to be a Source of Disease, by John Grove + +*** END OF THIS PROJECT GUTENBERG EBOOK EPIDEMICS EXAMINED *** + +***** This file should be named 34603.txt or 34603.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/3/4/6/0/34603/ + +Produced by Bryan Ness, Keith Edkins and the Online +Distributed Proofreading Team at http://www.pgdp.net (This +file was produced from images generously made available +by The Internet Archive/American Libraries.) + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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