diff options
Diffstat (limited to '1708-h')
| -rw-r--r-- | 1708-h/1708-h.htm | 9358 |
1 files changed, 9358 insertions, 0 deletions
diff --git a/1708-h/1708-h.htm b/1708-h/1708-h.htm new file mode 100644 index 0000000..7aa5a1b --- /dev/null +++ b/1708-h/1708-h.htm @@ -0,0 +1,9358 @@ +<?xml version="1.0" encoding="us-ascii"?> + +<!DOCTYPE html + PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd" > + +<html xmlns="http://www.w3.org/1999/xhtml" lang="en"> + <head> + <title> + A History of Science, Vol. IV by Henry Smith Williams + </title> + <style type="text/css" xml:space="preserve"> + + body { margin:5%; background:#faebd0; text-align:justify} + P { text-indent: 1em; margin-top: .25em; margin-bottom: .25em; } + H1,H2,H3,H4,H5,H6 { text-align: center; margin-left: 15%; margin-right: 15%; } + hr { width: 50%; text-align: center;} + .foot { margin-left: 20%; margin-right: 20%; text-align: justify; text-indent: -3em; font-size: 90%; } + blockquote {font-size: 97%; font-style: italic; margin-left: 10%; margin-right: 10%;} + .mynote {background-color: #DDE; color: #000; padding: .5em; margin-left: 10%; margin-right: 10%; font-family: sans-serif; font-size: 95%;} + .toc { margin-left: 10%; margin-bottom: .75em;} + .toc2 { margin-left: 20%;} + div.fig { display:block; margin:0 auto; text-align:center; } + div.middle { margin-left: 20%; margin-right: 20%; text-align: justify; } + .figleft {float: left; margin-left: 0%; margin-right: 1%;} + .figright {float: right; margin-right: 0%; margin-left: 1%;} + .pagenum {display:inline; font-size: 70%; font-style:normal; + margin: 0; padding: 0; position: absolute; right: 1%; + text-align: right;} + pre { font-style: italic; font-size: 90%; margin-left: 10%;} + +</style> + </head> + <body> +<pre xml:space="preserve"> + +The Project Gutenberg EBook of A History of Science, Volume 4(of 5), by +Henry Smith Williams + +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: A History of Science, Volume 4(of 5) + +Author: Henry Smith Williams + +Release Date: November 18, 2009 [EBook #1708] +Last Updated: January 26, 2013 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK HISTORY OF SCIENCE, V4 *** + + + + +Produced by Charles Keller, and David Widger + + + + + + +</pre> + <p> + <br /><br /> + </p> + <h1> + A HISTORY OF SCIENCE + </h1> + <h2> + BY HENRY SMITH WILLIAMS, M.D., LL.D. <br /> <br /> <br /> ASSISTED BY EDWARD + H. WILLIAMS, M.D. <br /> <br /> <br /> IN FIVE VOLUMES <br /> <br /> VOLUME IV. + </h2> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> + </p> + <blockquote> + <p class="toc"> + <big><b>CONTENTS</b></big> + </p> + <p> + <br /> <a href="#link2H_4_0001"> <b>BOOK IV. MODERN DEVELOPMENT OF THE + CHEMICAL AND BIOLOGICAL SCIENCES</b> </a><br /> <br /> <br /> + </p> + <p class="toc"> + <a href="#link2H_4_0002"> I. THE PHLOGISTON THEORY IN CHEMISTRY </a> + </p> + <p class="toc"> + <a href="#link2H_4_0003"> II. THE BEGINNINGS OF MODERN CHEMISTRY </a> + </p> + <p class="toc"> + <a href="#link2H_4_0004"> III. CHEMISTRY SINCE THE TIME OF DALTON </a> + </p> + <p class="toc"> + <a href="#link2H_4_0005"> IV. ANATOMY AND PHYSIOLOGY IN THE EIGHTEENTH + CENTURY </a> + </p> + <p class="toc"> + <a href="#link2H_4_0006"> V. ANATOMY AND PHYSIOLOGY IN THE NINETEENTH + CENTURY </a> + </p> + <p class="toc"> + <a href="#link2H_4_0007"> VI. THEORIES OF ORGANIC EVOLUTION </a> + </p> + <p class="toc"> + <a href="#link2H_4_0008"> VII. EIGHTEENTH-CENTURY MEDICINE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0009"> VIII. NINETEENTH-CENTURY MEDICINE </a> + </p> + <p class="toc"> + <a href="#link2H_4_0010"> IX. THE NEW SCIENCE OF EXPERIMENTAL PSYCHOLOGY + </a> + </p> + <p class="toc"> + <a href="#link2H_4_0011"> X. THE NEW SCIENCE OF ORIENTAL ARCHAEOLOGY + </a> + </p> + <p class="toc"> + <a href="#link2H_APPE"> APPENDIX </a> + </p> + </blockquote> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a name="link2H_4_0001" id="link2H_4_0001"> + <!-- H2 anchor --> </a> + </p> + <h2> + BOOK IV. MODERN DEVELOPMENT OF THE CHEMICAL AND BIOLOGICAL SCIENCES + </h2> + <p> + AS regards chronology, the epoch covered in the present volume is + identical with that viewed in the preceding one. But now as regards + subject matter we pass on to those diverse phases of the physical world + which are the field of the chemist, and to those yet more intricate + processes which have to do with living organisms. So radical are the + changes here that we seem to be entering new worlds; and yet, here as + before, there are intimations of the new discoveries away back in the + Greek days. The solution of the problem of respiration will remind us that + Anaxagoras half guessed the secret; and in those diversified studies which + tell us of the Daltonian atom in its wonderful transmutations, we shall be + reminded again of the Clazomenian philosopher and his successor + Democritus. + </p> + <p> + Yet we should press the analogy much too far were we to intimate that the + Greek of the elder day or any thinker of a more recent period had + penetrated, even in the vaguest way, all of the mysteries that the + nineteenth century has revealed in the fields of chemistry and biology. At + the very most the insight of those great Greeks and of the wonderful + seventeenth-century philosophers who so often seemed on the verge of our + later discoveries did no more than vaguely anticipate their successors of + this later century. To gain an accurate, really specific knowledge of the + properties of elementary bodies was reserved for the chemists of a recent + epoch. The vague Greek questionings as to organic evolution were + world-wide from the precise inductions of a Darwin. If the mediaeval + Arabian endeavored to dull the knife of the surgeon with the use of drugs, + his results hardly merit to be termed even an anticipation of modern + anaesthesia. And when we speak of preventive medicine—of + bacteriology in all its phases—we have to do with a marvellous field + of which no previous generation of men had even the slightest inkling. + </p> + <p> + All in all, then, those that lie before us are perhaps the most wonderful + and the most fascinating of all the fields of science. As the chapters of + the preceding book carried us out into a macrocosm of inconceivable + magnitude, our present studies are to reveal a microcosm of equally + inconceivable smallness. As the studies of the physicist attempted to + reveal the very nature of matter and of energy, we have now to seek the + solution of the yet more inscrutable problems of life and of mind. + </p> + <p> + <a name="link2H_4_0002" id="link2H_4_0002"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + I. THE PHLOGISTON THEORY IN CHEMISTRY + </h2> + <p> + The development of the science of chemistry from the "science" of alchemy + is a striking example of the complete revolution in the attitude of + observers in the field of science. As has been pointed out in a preceding + chapter, the alchemist, having a preconceived idea of how things should + be, made all his experiments to prove his preconceived theory; while the + chemist reverses this attitude of mind and bases his conceptions on the + results of his laboratory experiments. In short, chemistry is what alchemy + never could be, an inductive science. But this transition from one point + of view to an exactly opposite one was necessarily a very slow process. + Ideas that have held undisputed sway over the minds of succeeding + generations for hundreds of years cannot be overthrown in a moment, unless + the agent of such an overthrow be so obvious that it cannot be challenged. + The rudimentary chemistry that overthrew alchemy had nothing so obvious + and palpable. + </p> + <p> + The great first step was the substitution of the one principle, + phlogiston, for the three principles, salt, sulphur, and mercury. We have + seen how the experiment of burning or calcining such a metal as lead + "destroyed" the lead as such, leaving an entirely different substance in + its place, and how the original metal could be restored by the addition of + wheat to the calcined product. To the alchemist this was "mortification" + and "revivification" of the metal. For, as pointed out by Paracelsus, + "anything that could be killed by man could also be revivified by him, + although this was not possible to the things killed by God." The burning + of such substances as wood, wax, oil, etc., was also looked upon as the + same "killing" process, and the fact that the alchemist was unable to + revivify them was regarded as simply the lack of skill on his part, and in + no wise affecting the theory itself. + </p> + <p> + But the iconoclastic spirit, if not the acceptance of all the teachings, + of the great Paracelsus had been gradually taking root among the better + class of alchemists, and about the middle of the seventeenth century + Robert Boyle (1626-1691) called attention to the possibility of making a + wrong deduction from the phenomenon of the calcination of the metals, + because of a very important factor, the action of the air, which was + generally overlooked. And he urged his colleagues of the laboratories to + give greater heed to certain other phenomena that might pass unnoticed in + the ordinary calcinating process. In his work, The Sceptical Chemist, he + showed the reasons for doubting the threefold constitution of matter; and + in his General History of the Air advanced some novel and carefully + studied theories as to the composition of the atmosphere. This was an + important step, and although Boyle is not directly responsible for the + phlogiston theory, it is probable that his experiments on the atmosphere + influenced considerably the real founders, Becker and Stahl. + </p> + <p> + Boyle gave very definitely his idea of how he thought air might be + composed. "I conjecture that the atmospherical air consists of three + different kinds of corpuscles," he says; "the first, those numberless + particles which, in the form of vapors or dry exhalations, ascend from the + earth, water, minerals, vegetables, animals, etc.; in a word, whatever + substances are elevated by the celestial or subterraneal heat, and thence + diffused into the atmosphere. The second may be yet more subtle, and + consist of those exceedingly minute atoms, the magnetical effluvia of the + earth, with other innumerable particles sent out from the bodies of the + celestial luminaries, and causing, by their influence, the idea of light + in us. The third sort is its characteristic and essential property, I mean + permanently elastic parts. Various hypotheses may be framed relating to + the structure of these later particles of the air. They might be resembled + to the springs of watches, coiled up and endeavoring to restore + themselves; to wool, which, being compressed, has an elastic force; to + slender wires of different substances, consistencies, lengths, and + thickness; in greater curls or less, near to, or remote from each other, + etc., yet all continuing springy, expansible, and compressible. Lastly, + they may also be compared to the thin shavings of different kinds of wood, + various in their lengths, breadth, and thickness. And this, perhaps, will + seem the most eligible hypothesis, because it, in some measure, + illustrates the production of the elastic particles we are considering. + For no art or curious instruments are required to make these shavings + whose curls are in no wise uniform, but seemingly casual; and what is more + remarkable, bodies that before seemed unelastic, as beams and blocks, will + afford them."(1) + </p> + <p> + Although this explanation of the composition of the air is most crude, it + had the effect of directing attention to the fact that the atmosphere is + not "mere nothingness," but a "something" with a definite composition, and + this served as a good foundation for future investigations. To be sure, + Boyle was neither the first nor the only chemist who had suspected that + the air was a mixture of gases, and not a simple one, and that only + certain of these gases take part in the process of calcination. Jean Rey, + a French physician, and John Mayow, an Englishman, had preformed + experiments which showed conclusively that the air was not a simple + substance; but Boyle's work was better known, and in its effect probably + more important. But with all Boyle's explanations of the composition of + air, he still believed that there was an inexplicable something, a "vital + substance," which he was unable to fathom, and which later became the + basis of Stahl's phlogiston theory. Commenting on this mysterious + substance, Boyle says: "The difficulty we find in keeping flame and fire + alive, though but for a little time, without air, renders it suspicious + that there be dispersed through the rest of the atmosphere some odd + substance, either of a solar, astral, or other foreign nature; on account + of which the air is so necessary to the substance of flame!" It was this + idea that attracted the attention of George Ernst Stahl (1660-1734), a + professor of medicine in the University of Halle, who later founded his + new theory upon it. Stahl's theory was a development of an earlier + chemist, Johann Joachim Becker (1635-1682), in whose footsteps he followed + and whose experiments he carried further. + </p> + <p> + In many experiments Stahl had been struck with the fact that certain + substances, while differing widely, from one another in many respects, + were alike in combustibility. From this he argued that all combustible + substances must contain a common principle, and this principle he named + phlogiston. This phlogiston he believed to be intimately associated in + combination with other substances in nature, and in that condition not + perceivable by the senses; but it was supposed to escape as a substance + burned, and become apparent to the senses as fire or flame. In other + words, phlogiston was something imprisoned in a combustible structure + (itself forming part of the structure), and only liberated when this + structure was destroyed. Fire, or flame, was FREE phlogiston, while the + imprisoned phlogiston was called COMBINED PHLOGISTON, or combined fire. + The peculiar quality of this strange substance was that it disliked + freedom and was always striving to conceal itself in some combustible + substance. Boyle's tentative suggestion that heat was simply motion was + apparently not accepted by Stahl, or perhaps it was unknown to him. + </p> + <p> + According to the phlogistic theory, the part remaining after a substance + was burned was simply the original substance deprived of phlogiston. To + restore the original combustible substance, it was necessary to heat the + residue of the combustion with something that burned easily, so that the + freed phlogiston might again combine with the ashes. This was explained by + the supposition that the more combustible a substance was the more + phlogiston it contained, and since free phlogiston sought always to + combine with some suitable substance, it was only necessary to mix the + phlogisticating agents, such as charcoal, phosphorus, oils, fats, etc., + with the ashes of the original substance, and heat the mixture, the + phlogiston thus freed uniting at once with the ashes. This theory fitted + very nicely as applied to the calcined lead revivified by the grains of + wheat, although with some other products of calcination it did not seem to + apply at all. + </p> + <p> + It will be seen from this that the phlogistic theory was a step towards + chemistry and away from alchemy. It led away from the idea of a "spirit" + in metals that could not be seen, felt, or appreciated by any of the + senses, and substituted for it a principle which, although a falsely + conceived one, was still much more tangible than the "spirit," since it + could be seen and felt as free phlogiston and weighed and measured as + combined phlogiston. The definiteness of the statement that a metal, for + example, was composed of phlogiston and an element was much less + enigmatic, even if wrong, than the statement of the alchemist that "metals + are produced by the spiritual action of the three principles, salt, + mercury, sulphur"—particularly when it is explained that salt, + mercury, and sulphur were really not what their names implied, and that + there was no universally accepted belief as to what they really were. + </p> + <p> + The metals, which are now regarded as elementary bodies, were considered + compounds by the phlogistians, and they believed that the calcining of a + metal was a process of simplification. They noted, however, that the + remains of calcination weighed more than the original product, and the + natural inference from this would be that the metal must have taken in + some substance rather than have given off anything. But the phlogistians + had not learned the all-important significance of weights, and their + explanation of variation in weight was either that such gain or loss was + an unimportant "accident" at best, or that phlogiston, being light, tended + to lighten any substance containing it, so that driving it out of the + metal by calcination naturally left the residue heavier. + </p> + <p> + At first the phlogiston theory seemed to explain in an indisputable way + all the known chemical phenomena. Gradually, however, as experiments + multiplied, it became evident that the plain theory as stated by Stahl and + his followers failed to explain satisfactorily certain laboratory + reactions. To meet these new conditions, certain modifications were + introduced from time to time, giving the theory a flexibility that would + allow it to cover all cases. But as the number of inexplicable experiments + continued to increase, and new modifications to the theory became + necessary, it was found that some of these modifications were directly + contradictory to others, and thus the simple theory became too cumbersome + from the number of its modifications. Its supporters disagreed among + themselves, first as to the explanation of certain phenomena that did not + seem to accord with the phlogistic theory, and a little later as to the + theory itself. But as yet there was no satisfactory substitute for this + theory, which, even if unsatisfactory, seemed better than anything that + had gone before or could be suggested. + </p> + <p> + But the good effects of the era of experimental research, to which the + theory of Stahl had given such an impetus, were showing in the attitude of + the experimenters. The works of some of the older writers, such as Boyle + and Hooke, were again sought out in their dusty corners and consulted, and + their surmises as to the possible mixture of various gases in the air were + more carefully considered. Still the phlogiston theory was firmly grounded + in the minds of the philosophers, who can hardly be censured for adhering + to it, at least until some satisfactory substitute was offered. The + foundation for such a theory was finally laid, as we shall see presently, + by the work of Black, Priestley, Cavendish, and Lavoisier, in the + eighteenth century, but the phlogiston theory cannot be said to have + finally succumbed until the opening years of the nineteenth century. + </p> + <p> + <a name="link2H_4_0003" id="link2H_4_0003"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + II. THE BEGINNINGS OF MODERN CHEMISTRY + </h2> + <h3> + THE "PNEUMATIC" CHEMISTS + </h3> + <p> + Modern chemistry may be said to have its beginning with the work of + Stephen Hales (1677-1761), who early in the eighteenth century began his + important study of the elasticity of air. Departing from the point of view + of most of the scientists of the time, he considered air to be "a fine + elastic fluid, with particles of very different nature floating in it"; + and he showed that these "particles" could be separated. He pointed out, + also, that various gases, or "airs," as he called them, were contained in + many solid substances. The importance of his work, however, lies in the + fact that his general studies were along lines leading away from the + accepted doctrines of the time, and that they gave the impetus to the + investigation of the properties of gases by such chemists as Black, + Priestley, Cavendish, and Lavoisier, whose specific discoveries are the + foundation-stones of modern chemistry. + </p> + <p> + JOSEPH BLACK + </p> + <p> + The careful studies of Hales were continued by his younger confrere, Dr. + Joseph Black (1728-1799), whose experiments in the weights of gases and + other chemicals were first steps in quantitative chemistry. But even more + important than his discoveries of chemical properties in general was his + discovery of the properties of carbonic-acid gas. + </p> + <p> + Black had been educated for the medical profession in the University of + Glasgow, being a friend and pupil of the famous Dr. William Cullen. But + his liking was for the chemical laboratory rather than for the practice of + medicine. Within three years after completing his medical course, and when + only twenty-three years of age, he made the discovery of the properties of + carbonic acid, which he called by the name of "fixed air." After + discovering this gas, Black made a long series of experiments, by which he + was able to show how widely it was distributed throughout nature. Thus, in + 1757, he discovered that the bubbles given off in the process of brewing, + where there was vegetable fermentation, were composed of it. To prove + this, he collected the contents of these bubbles in a bottle containing + lime-water. When this bottle was shaken violently, so that the lime-water + and the carbonic acid became thoroughly mixed, an insoluble white powder + was precipitated from the solution, the carbonic acid having combined + chemically with the lime to form the insoluble calcium carbonate, or + chalk. This experiment suggested another. Fixing a piece of burning + charcoal in the end of a bellows, he arranged a tube so that the gas + coming from the charcoal would pass through the lime-water, and, as in the + case of the bubbles from the brewer's vat, he found that the white + precipitate was thrown down; in short, that carbonic acid was given off in + combustion. Shortly after, Black discovered that by blowing through a + glass tube inserted into lime-water, chalk was precipitated, thus proving + that carbonic acid was being constantly thrown off in respiration. + </p> + <p> + The effect of Black's discoveries was revolutionary, and the attitude of + mind of the chemists towards gases, or "airs," was changed from that time + forward. Most of the chemists, however, attempted to harmonize the new + facts with the older theories—to explain all the phenomena on the + basis of the phlogiston theory, which was still dominant. But while many + of Black's discoveries could not be made to harmonize with that theory, + they did not directly overthrow it. It required the additional discoveries + of some of Black's fellow-scientists to complete its downfall, as we shall + see. + </p> + <p> + HENRY CAVENDISH + </p> + <p> + This work of Black's was followed by the equally important work of his + former pupil, Henry Cavendish (1731-1810), whose discovery of the + composition of many substances, notably of nitric acid and of water, was + of great importance, adding another link to the important chain of + evidence against the phlogiston theory. Cavendish is one of the most + eccentric figures in the history of science, being widely known in his own + time for his immense wealth and brilliant intellect, and also for his + peculiarities and his morbid sensibility, which made him dread society, + and probably did much in determining his career. Fortunately for him, and + incidentally for the cause of science, he was able to pursue laboratory + investigations without being obliged to mingle with his dreaded + fellow-mortals, his every want being provided for by the immense fortune + inherited from his father and an uncle. + </p> + <p> + When a young man, as a pupil of Dr. Black, he had become imbued with the + enthusiasm of his teacher, continuing Black's investigations as to the + properties of carbonic-acid gas when free and in combination. One of his + first investigations was reported in 1766, when he communicated to the + Royal Society his experiments for ascertaining the properties of + carbonic-acid and hydrogen gas, in which he first showed the possibility + of weighing permanently elastic fluids, although Torricelli had before + this shown the relative weights of a column of air and a column of + mercury. Other important experiments were continued by Cavendish, and in + 1784 he announced his discovery of the composition of water, thus robbing + it of its time-honored position as an "element." But his claim to priority + in this discovery was at once disputed by his fellow-countryman James Watt + and by the Frenchman Lavoisier. Lavoisier's claim was soon disallowed even + by his own countrymen, but for many years a bitter controversy was carried + on by the partisans of Watt and Cavendish. The two principals, however, + seem never to have entered into this controversy with anything like the + same ardor as some of their successors, as they remained on the best of + terms.(1) It is certain, at any rate, that Cavendish announced his + discovery officially before Watt claimed that the announcement had been + previously made by him, "and, whether right or wrong, the honor of + scientific discoveries seems to be accorded naturally to the man who first + publishes a demonstration of his discovery." Englishmen very generally + admit the justness of Cavendish's claim, although the French scientist + Arago, after reviewing the evidence carefully in 1833, decided in favor of + Watt. + </p> + <p> + It appears that something like a year before Cavendish made known his + complete demonstration of the composition of water, Watt communicated to + the Royal Society a suggestion that water was composed of + "dephlogisticated air (oxygen) and phlogiston (hydrogen) deprived of part + of its latent heat." Cavendish knew of the suggestion, but in his + experiments refuted the idea that the hydrogen lost any of its latent + heat. Furthermore, Watt merely suggested the possible composition without + proving it, although his idea was practically correct, if we can rightly + interpret the vagaries of the nomenclature then in use. But had Watt taken + the steps to demonstrate his theory, the great "Water Controversy" would + have been avoided. Cavendish's report of his discovery to the Royal + Society covers something like forty pages of printed matter. In this he + shows how, by passing an electric spark through a closed jar containing a + mixture of hydrogen gas and oxygen, water is invariably formed, apparently + by the union of the two gases. The experiment was first tried with + hydrogen and common air, the oxygen of the air uniting with the hydrogen + to form water, leaving the nitrogen of the air still to be accounted for. + With pure oxygen and hydrogen, however, Cavendish found that pure water + was formed, leaving slight traces of any other, substance which might not + be interpreted as being Chemical impurities. There was only one possible + explanation of this phenomenon—that hydrogen and oxygen, when + combined, form water. + </p> + <p> + "By experiments with the globe it appeared," wrote Cavendish, "that when + inflammable and common air are exploded in a proper proportion, almost all + the inflammable air, and near one-fifth the common air, lose their + elasticity and are condensed into dew. And by this experiment it appears + that this dew is plain water, and consequently that almost all the + inflammable air is turned into pure water. + </p> + <p> + "In order to examine the nature of the matter condensed on firing a + mixture of dephlogisticated and inflammable air, I took a glass globe, + holding 8800 grain measures, furnished with a brass cock and an apparatus + for firing by electricity. This globe was well exhausted by an air-pump, + and then filled with a mixture of inflammable and dephlogisticated air by + shutting the cock, fastening the bent glass tube into its mouth, and + letting up the end of it into a glass jar inverted into water and + containing a mixture of 19,500 grain measures of dephlogisticated air, and + 37,000 of inflammable air; so that, upon opening the cock, some of this + mixed air rushed through the bent tube and filled the globe. The cock was + then shut and the included air fired by electricity, by means of which + almost all of it lost its elasticity (was condensed into water vapors). + The cock was then again opened so as to let in more of the same air to + supply the place of that destroyed by the explosion, which was again + fired, and the operation continued till almost the whole of the mixture + was let into the globe and exploded. By this means, though the globe held + not more than a sixth part of the mixture, almost the whole of it was + exploded therein without any fresh exhaustion of the globe." + </p> + <p> + At first this condensed matter was "acid to the taste and contained two + grains of nitre," but Cavendish, suspecting that this was due to + impurities, tried another experiment that proved conclusively that his + opinions were correct. "I therefore made another experiment," he says, + "with some more of the same air from plants in which the proportion of + inflammable air was greater, so that the burnt air was almost completely + phlogisticated, its standard being one-tenth. The condensed liquor was + then not at all acid, but seemed pure water." + </p> + <p> + From these experiments he concludes "that when a mixture of inflammable + and dephlogisticated air is exploded, in such proportions that the burnt + air is not much phlogisticated, the condensed liquor contains a little + acid which is always of the nitrous kind, whatever substance the + dephlogisticated air is procured from; but if the proportion be such that + the burnt air is almost entirely phlogisticated, the condensed liquor is + not at all acid, but seems pure water, without any addition whatever."(2) + </p> + <p> + These same experiments, which were undertaken to discover the composition + of water, led him to discover also the composition of nitric acid. He had + observed that, in the combustion of hydrogen gas with common air, the + water was slightly tinged with acid, but that this was not the case when + pure oxygen gas was used. Acting upon this observation, he devised an + experiment to determine the nature of this acid. He constructed an + apparatus whereby an electric spark was passed through a vessel containing + common air. After this process had been carried on for several weeks a + small amount of liquid was formed. This liquid combined with a solution of + potash to form common nitre, which "detonated with charcoal, sparkled when + paper impregnated with it was burned, and gave out nitrous fumes when + sulphuric acid was poured on it." In other words, the liquid was shown to + be nitric acid. Now, since nothing but pure air had been used in the + initial experiment, and since air is composed of nitrogen and oxygen, + there seemed no room to doubt that nitric acid is a combination of + nitrogen and oxygen. + </p> + <p> + This discovery of the nature of nitric acid seems to have been about the + last work of importance that Cavendish did in the field of chemistry, + although almost to the hour of his death he was constantly occupied with + scientific observations. Even in the last moments of his life this habit + asserted itself, according to Lord Brougham. "He died on March 10, 1810, + after a short illness, probably the first, as well as the last, which he + ever suffered. His habit of curious observation continued to the end. He + was desirous of marking the progress of the disease and the gradual + extinction of the vital powers. With these ends in view, that he might not + be disturbed, he desired to be left alone. His servant, returning sooner + than he had wished, was ordered again to leave the chamber of death, and + when he came back a second time he found his master had expired."(3) + </p> + <p> + JOSEPH PRIESTLEY + </p> + <p> + While the opulent but diffident Cavendish was making his important + discoveries, another Englishman, a poor country preacher named Joseph + Priestley (1733-1804) was not only rivalling him, but, if anything, + outstripping him in the pursuit of chemical discoveries. In 1761 this + young minister was given a position as tutor in a nonconformist academy at + Warrington, and here, for six years, he was able to pursue his studies in + chemistry and electricity. In 1766, while on a visit to London, he met + Benjamin Franklin, at whose suggestion he published his History of + Electricity. From this time on he made steady progress in scientific + investigations, keeping up his ecclesiastical duties at the same time. In + 1780 he removed to Birmingham, having there for associates such scientists + as James Watt, Boulton, and Erasmus Darwin. + </p> + <p> + Eleven years later, on the anniversary of the fall of the Bastile in + Paris, a fanatical mob, knowing Priestley's sympathies with the French + revolutionists, attacked his house and chapel, burning both and destroying + a great number of valuable papers and scientific instruments. Priestley + and his family escaped violence by flight, but his most cherished + possessions were destroyed; and three years later he quitted England + forever, removing to the United States, whose struggle for liberty he had + championed. The last ten years of his life were spent at Northumberland, + Pennsylvania, where he continued his scientific researches. + </p> + <p> + Early in his scientific career Priestley began investigations upon the + "fixed air" of Dr. Black, and, oddly enough, he was stimulated to this by + the same thing that had influenced Black—that is, his residence in + the immediate neighborhood of a brewery. It was during the course of a + series of experiments on this and other gases that he made his greatest + discovery, that of oxygen, or "dephlogisticated air," as he called it. The + story of this important discovery is probably best told in Priestley's own + words: + </p> + <p> + "There are, I believe, very few maxims in philosophy that have laid firmer + hold upon the mind than that air, meaning atmospheric air, is a simple + elementary substance, indestructible and unalterable, at least as much so + as water is supposed to be. In the course of my inquiries I was, however, + soon satisfied that atmospheric air is not an unalterable thing; for that, + according to my first hypothesis, the phlogiston with which it becomes + loaded from bodies burning in it, and the animals breathing it, and + various other chemical processes, so far alters and depraves it as to + render it altogether unfit for inflammation, respiration, and other + purposes to which it is subservient; and I had discovered that agitation + in the water, the process of vegetation, and probably other natural + processes, restore it to its original purity.... + </p> + <p> + "Having procured a lens of twelve inches diameter and twenty inches local + distance, I proceeded with the greatest alacrity, by the help of it, to + discover what kind of air a great variety of substances would yield, + putting them into the vessel, which I filled with quicksilver, and kept + inverted in a basin of the same .... With this apparatus, after a variety + of experiments.... on the 1st of August, 1774, I endeavored to extract air + from mercurius calcinatus per se; and I presently found that, by means of + this lens, air was expelled from it very readily. Having got about three + or four times as much as the bulk of my materials, I admitted water to it, + and found that it was not imbibed by it. But what surprised me more than I + can express was that a candle burned in this air with a remarkably + vigorous flame, very much like that enlarged flame with which a candle + burns in nitrous oxide, exposed to iron or liver of sulphur; but as I had + got nothing like this remarkable appearance from any kind of air besides + this particular modification of vitrous air, and I knew no vitrous acid + was used in the preparation of mercurius calcinatus, I was utterly at a + loss to account for it."(4) + </p> + <p> + The "new air" was, of course, oxygen. Priestley at once proceeded to + examine it by a long series of careful experiments, in which, as will be + seen, he discovered most of the remarkable qualities of this gas. + Continuing his description of these experiments, he says: + </p> + <p> + "The flame of the candle, besides being larger, burned with more splendor + and heat than in that species of nitrous air; and a piece of red-hot wood + sparkled in it, exactly like paper dipped in a solution of nitre, and it + consumed very fast; an experiment that I had never thought of trying with + dephlogisticated nitrous air. + </p> + <p> + "... I had so little suspicion of the air from the mercurius calcinatus, + etc., being wholesome, that I had not even thought of applying it to the + test of nitrous air; but thinking (as my reader must imagine I frequently + must have done) on the candle burning in it after long agitation in water, + it occurred to me at last to make the experiment; and, putting one measure + of nitrous air to two measures of this air, I found not only that it was + diminished, but that it was diminished quite as much as common air, and + that the redness of the mixture was likewise equal to a similar mixture of + nitrous and common air.... The next day I was more surprised than ever I + had been before with finding that, after the above-mentioned mixture of + nitrous air and the air from mercurius calcinatus had stood all night,... + a candle burned in it, even better than in common air." + </p> + <p> + A little later Priestley discovered that "dephlogisticated air... is a + principal element in the composition of acids, and may be extracted by + means of heat from many substances which contain them.... It is likewise + produced by the action of light upon green vegetables; and this seems to + be the chief means employed to preserve the purity of the atmosphere." + </p> + <p> + This recognition of the important part played by oxygen in the atmosphere + led Priestley to make some experiments upon mice and insects, and finally + upon himself, by inhalations of the pure gas. "The feeling in my lungs," + he said, "was not sensibly different from that of common air, but I + fancied that my breathing felt peculiarly light and easy for some time + afterwards. Who can tell but that in time this pure air may become a + fashionable article in luxury?... Perhaps we may from these experiments + see that though pure dephlogisticated air might be useful as a medicine, + it might not be so proper for us in the usual healthy state of the body." + </p> + <p> + This suggestion as to the possible usefulness of oxygen as a medicine was + prophetic. A century later the use of oxygen had become a matter of + routine practice with many physicians. Even in Priestley's own time such + men as Dr. John Hunter expressed their belief in its efficacy in certain + conditions, as we shall see, but its value in medicine was not fully + appreciated until several generations later. + </p> + <p> + Several years after discovering oxygen Priestley thus summarized its + properties: "It is this ingredient in the atmospheric air that enables it + to support combustion and animal life. By means of it most intense heat + may be produced, and in the purest of it animals will live nearly five + times as long as in an equal quantity of atmospheric air. In respiration, + part of this air, passing the membranes of the lungs, unites with the + blood and imparts to it its florid color, while the remainder, uniting + with phlogiston exhaled from venous blood, forms mixed air. It is + dephlogisticated air combined with water that enables fishes to live in + it."(5) + </p> + <p> + KARL WILHELM SCHEELE + </p> + <p> + The discovery of oxygen was the last but most important blow to the + tottering phlogiston theory, though Priestley himself would not admit it. + But before considering the final steps in the overthrow of Stahl's famous + theory and the establishment of modern chemistry, we must review the work + of another great chemist, Karl Wilhelm Scheele (1742-1786), of Sweden, who + discovered oxygen quite independently, although later than Priestley. In + the matter of brilliant discoveries in a brief space of time Scheele + probably eclipsed all his great contemporaries. He had a veritable genius + for interpreting chemical reactions and discovering new substances, in + this respect rivalling Priestley himself. Unlike Priestley, however, he + planned all his experiments along the lines of definite theories from the + beginning, the results obtained being the logical outcome of a + predetermined plan. + </p> + <p> + Scheele was the son of a merchant of Stralsund, Pomerania, which then + belonged to Sweden. As a boy in school he showed so little aptitude for + the study of languages that he was apprenticed to an apothecary at the age + of fourteen. In this work he became at once greatly interested, and, when + not attending to his duties in the dispensary, he was busy day and night + making experiments or studying books on chemistry. In 1775, still employed + as an apothecary, he moved to Stockholm, and soon after he sent to + Bergman, the leading chemist of Sweden, his first discovery—that of + tartaric acid, which he had isolated from cream of tartar. This was the + beginning of his career of discovery, and from that time on until his + death he sent forth accounts of new discoveries almost uninterruptedly. + Meanwhile he was performing the duties of an ordinary apothecary, and + struggling against poverty. His treatise upon Air and Fire appeared in + 1777. In this remarkable book he tells of his discovery of oxygen—"empyreal" + or "fire-air," as he calls it—which he seems to have made + independently and without ever having heard of the previous discovery by + Priestley. In this book, also, he shows that air is composed chiefly of + oxygen and nitrogen gas. + </p> + <p> + Early in his experimental career Scheele undertook the solution of the + composition of black oxide of manganese, a substance that had long puzzled + the chemists. He not only succeeded in this, but incidentally in the + course of this series of experiments he discovered oxygen, baryta, and + chlorine, the last of far greater importance, at least commercially, than + the real object of his search. In speaking of the experiment in which the + discovery was made he says: + </p> + <p> + "When marine (hydrochloric) acid stood over manganese in the cold it + acquired a dark reddish-brown color. As manganese does not give any + colorless solution without uniting with phlogiston (probably meaning + hydrogen), it follows that marine acid can dissolve it without this + principle. But such a solution has a blue or red color. The color is here + more brown than red, the reason being that the very finest portions of the + manganese, which do not sink so easily, swim in the red solution; for + without these fine particles the solution is red, and red mixed with black + is brown. The manganese has here attached itself so loosely to acidum + salis that the water can precipitate it, and this precipitate behaves like + ordinary manganese. When, now, the mixture of manganese and spiritus salis + was set to digest, there arose an effervescence and smell of aqua + regis."(6) + </p> + <p> + The "effervescence" he refers to was chlorine, which he proceeded to + confine in a suitable vessel and examine more fully. He described it as + having a "quite characteristically suffocating smell," which was very + offensive. He very soon noted the decolorizing or bleaching effects of + this now product, finding that it decolorized flowers, vegetables, and + many other substances. + </p> + <p> + Commercially this discovery of chlorine was of enormous importance and the + practical application of this new chemical in bleaching cloth soon + supplanted the old process of crofting—that is, bleaching by + spreading the cloth upon the grass. But although Scheele first pointed out + the bleaching quality of his newly discovered gas, it was the French + savant, Berthollet, who, acting upon Scheele's discovery that the new gas + would decolorize vegetables and flowers, was led to suspect that this + property might be turned to account in destroying the color of cloth. In + 1785 he read a paper before the Academy of Sciences of Paris, in which he + showed that bleaching by chlorine was entirely satisfactory, the color but + not the substance of the cloth being affected. He had experimented + previously and found that the chlorine gas was soluble in water and could + thus be made practically available for bleaching purposes. In 1786 James + Watt examined specimens of the bleached cloth made by Berthollet, and upon + his return to England first instituted the process of practical bleaching. + His process, however, was not entirely satisfactory, and, after undergoing + various modifications and improvements, it was finally made thoroughly + practicable by Mr. Tennant, who hit upon a compound of chlorine and lime—the + chloride of lime—which was a comparatively cheap chemical product, + and answered the purpose better even than chlorine itself. + </p> + <p> + To appreciate how momentous this discovery was to cloth manufacturers, it + should be remembered that the old process of bleaching consumed an entire + summer for the whitening of a single piece of linen; the new process + reduced the period to a few hours. To be sure, lime had been used with + fair success previous to Tennant's discovery, but successful and practical + bleaching by a solution of chloride of lime was first made possible by him + and through Scheele's discovery of chlorine. + </p> + <p> + Until the time of Scheele the great subject of organic chemistry had + remained practically unexplored, but under the touch of his marvellous + inventive genius new methods of isolating and studying animal and + vegetable products were introduced, and a large number of acids and other + organic compounds prepared that had been hitherto unknown. His + explanations of chemical phenomena were based on the phlogiston theory, in + which, like Priestley, he always, believed. Although in error in this + respect, he was, nevertheless, able to make his discoveries with extremely + accurate interpretations. A brief epitome of the list of some of his more + important discoveries conveys some idea, of his fertility of mind as well + as his industry. In 1780 he discovered lactic acid,(7) and showed that it + was the substance that caused the acidity of sour milk; and in the same + year he discovered mucic acid. Next followed the discovery of tungstic + acid, and in 1783 he added to his list of useful discoveries that of + glycerine. Then in rapid succession came his announcements of the new + vegetable products citric, malic, oxalic, and gallic acids. Scheele not + only made the discoveries, but told the world how he had made them—how + any chemist might have made them if he chose—for he never considered + that he had really discovered any substance until he had made it, + decomposed it, and made it again. + </p> + <p> + His experiments on Prussian blue are most interesting, not only because of + the enormous amount of work involved and the skill he displayed in his + experiments, but because all the time the chemist was handling, smelling, + and even tasting a compound of one of the most deadly poisons, ignorant of + the fact that the substance was a dangerous one to handle. His escape from + injury seems almost miraculous; for his experiments, which were most + elaborate, extended over a considerable period of time, during which he + seems to have handled this chemical with impunity. + </p> + <p> + While only forty years of age and just at the zenith of his fame, Scheele + was stricken by a fatal illness, probably induced by his ceaseless labor + and exposure. It is gratifying to know, however, that during the last + eight or nine years of his life he had been less bound down by pecuniary + difficulties than before, as Bergman had obtained for him an annual grant + from the Academy. But it was characteristic of the man that, while + devoting one-sixth of the amount of this grant to his personal wants, the + remaining five-sixths was devoted to the expense of his experiments. + </p> + <p> + LAVOISIER AND THE FOUNDATION OF MODERN CHEMISTRY + </p> + <p> + The time was ripe for formulating the correct theory of chemical + composition: it needed but the master hand to mould the materials into the + proper shape. The discoveries in chemistry during the eighteenth century + had been far-reaching and revolutionary in character. A brief review of + these discoveries shows how completely they had subverted the old ideas of + chemical elements and chemical compounds. Of the four substances earth, + air, fire, and water, for many centuries believed to be elementary bodies, + not one has stood the test of the eighteenth-century chemists. Earth had + long since ceased to be regarded as an element, and water and air had + suffered the same fate in this century. And now at last fire itself, the + last of the four "elements" and the keystone to the phlogiston arch, was + shown to be nothing more than one of the manifestations of the new + element, oxygen, and not "phlogiston" or any other intangible substance. + </p> + <p> + In this epoch of chemical discoveries England had produced such mental + giants and pioneers in science as Black, Priestley, and Cavendish; Sweden + had given the world Scheele and Bergman, whose work, added to that of + their English confreres, had laid the broad base of chemistry as a + science; but it was for France to produce a man who gave the final touches + to the broad but rough workmanship of its foundation, and establish it as + the science of modern chemistry. It was for Antoine Laurent Lavoisier + (1743-1794) to gather together, interpret correctly, rename, and classify + the wealth of facts that his immediate predecessors and contemporaries had + given to the world. + </p> + <p> + The attitude of the mother-countries towards these illustrious sons is an + interesting piece of history. Sweden honored and rewarded Scheele and + Bergman for their efforts; England received the intellectuality of + Cavendish with less appreciation than the Continent, and a fanatical mob + drove Priestley out of the country; while France, by sending Lavoisier to + the guillotine, demonstrated how dangerous it was, at that time at least, + for an intelligent Frenchman to serve his fellowman and his country well. + </p> + <p> + "The revolution brought about by Lavoisier in science," says Hoefer, + "coincides by a singular act of destiny with another revolution, much + greater indeed, going on then in the political and social world. Both + happened on the same soil, at the same epoch, among the same people; and + both marked the commencement of a new era in their respective spheres."(8) + </p> + <p> + Lavoisier was born in Paris, and being the son of an opulent family, was + educated under the instruction of the best teachers of the day. With + Lacaille he studied mathematics and astronomy; with Jussieu, botany; and, + finally, chemistry under Rouelle. His first work of importance was a paper + on the practical illumination of the streets of Paris, for which a prize + had been offered by M. de Sartine, the chief of police. This prize was not + awarded to Lavoisier, but his suggestions were of such importance that the + king directed that a gold medal be bestowed upon the young author at the + public sitting of the Academy in April, 1776. Two years later, at the age + of thirty-five, Lavoisier was admitted a member of the Academy. + </p> + <p> + In this same year he began to devote himself almost exclusively to + chemical inquiries, and established a laboratory in his home, fitted with + all manner of costly apparatus and chemicals. Here he was in constant + communication with the great men of science of Paris, to all of whom his + doors were thrown open. One of his first undertakings in this laboratory + was to demonstrate that water could not be converted into earth by + repeated distillations, as was generally advocated; and to show also that + there was no foundation to the existing belief that it was possible to + convert water into a gas so "elastic" as to pass through the pores of a + vessel. He demonstrated the fallaciousness of both these theories in + 1768-1769 by elaborate experiments, a single investigation of this series + occupying one hundred and one days. + </p> + <p> + In 1771 he gave the first blow to the phlogiston theory by his experiments + on the calcination of metals. It will be recalled that one basis for the + belief in phlogiston was the fact that when a metal was calcined it was + converted into an ash, giving up its "phlogiston" in the process. To + restore the metal, it was necessary to add some substance such as wheat or + charcoal to the ash. Lavoisier, in examining this process of restoration, + found that there was always evolved a great quantity of "air," which he + supposed to be "fixed air" or carbonic acid—the same that escapes in + effervescence of alkalies and calcareous earths, and in the fermentation + of liquors. He then examined the process of calcination, whereby the + phlogiston of the metal was supposed to have been drawn off. But far from + finding that phlogiston or any other substance had been driven off, he + found that something had been taken on: that the metal "absorbed air," and + that the increased weight of the metal corresponded to the amount of air + "absorbed." Meanwhile he was within grasp of two great discoveries, that + of oxygen and of the composition of the air, which Priestley made some two + years later. + </p> + <p> + The next important inquiry of this great Frenchman was as to the + composition of diamonds. With the great lens of Tschirnhausen belonging to + the Academy he succeeded in burning up several diamonds, regardless of + expense, which, thanks to his inheritance, he could ignore. In this + process he found that a gas was given off which precipitated lime from + water, and proved to be carbonic acid. Observing this, and experimenting + with other substances known to give off carbonic acid in the same manner, + he was evidently impressed with the now well-known fact that diamond and + charcoal are chemically the same. But if he did really believe it, he was + cautious in expressing his belief fully. "We should never have expected," + he says, "to find any relation between charcoal and diamond, and it would + be unreasonable to push this analogy too far; it only exists because both + substances seem to be properly ranged in the class of combustible bodies, + and because they are of all these bodies the most fixed when kept from + contact with air." + </p> + <p> + As we have seen, Priestley, in 1774, had discovered oxygen, or + "dephlogisticated air." Four years later Lavoisier first advanced his + theory that this element discovered by Priestley was the universal + acidifying or oxygenating principle, which, when combined with charcoal or + carbon, formed carbonic acid; when combined with sulphur, formed sulphuric + (or vitriolic) acid; with nitrogen, formed nitric acid, etc., and when + combined with the metals formed oxides, or calcides. Furthermore, he + postulated the theory that combustion was not due to any such illusive + thing as "phlogiston," since this did not exist, and it seemed to him that + the phenomena of combustion heretofore attributed to phlogiston could be + explained by the action of the new element oxygen and heat. This was the + final blow to the phlogiston theory, which, although it had been tottering + for some time, had not been completely overthrown. + </p> + <p> + In 1787 Lavoisier, in conjunction with Guyon de Morveau, Berthollet, and + Fourcroy, introduced the reform in chemical nomenclature which until then + had remained practically unchanged since alchemical days. Such expressions + as "dephlogisticated" and "phlogisticated" would obviously have little + meaning to a generation who were no longer to believe in the existence of + phlogiston. It was appropriate that a revolution in chemical thought + should be accompanied by a corresponding revolution in chemical names, and + to Lavoisier belongs chiefly the credit of bringing about this revolution. + In his Elements of Chemistry he made use of this new nomenclature, and it + seemed so clearly an improvement over the old that the scientific world + hastened to adopt it. In this connection Lavoisier says: "We have, + therefore, laid aside the expression metallic calx altogether, and have + substituted in its place the word oxide. By this it may be seen that the + language we have adopted is both copious and expressive. The first or + lowest degree of oxygenation in bodies converts them into oxides; a second + degree of additional oxygenation constitutes the class of acids of which + the specific names drawn from their particular bases terminate in ous, as + in the nitrous and the sulphurous acids. The third degree of oxygenation + changes these into the species of acids distinguished by the termination + in ic, as the nitric and sulphuric acids; and, lastly, we can express a + fourth or higher degree of oxygenation by adding the word oxygenated to + the name of the acid, as has already been done with oxygenated muriatic + acid."(9) + </p> + <p> + This new work when given to the world was not merely an epoch-making book; + it was revolutionary. It not only discarded phlogiston altogether, but set + forth that metals are simple elements, not compounds of "earth" and + "phlogiston." It upheld Cavendish's demonstration that water itself, like + air, is a compound of oxygen with another element. In short, it was + scientific chemistry, in the modern acceptance of the term. + </p> + <p> + Lavoisier's observations on combustion are at once important and + interesting: "Combustion," he says, "... is the decomposition of oxygen + produced by a combustible body. The oxygen which forms the base of this + gas is absorbed by and enters into combination with the burning body, + while the caloric and light are set free. Every combustion necessarily + supposes oxygenation; whereas, on the contrary, every oxygenation does not + necessarily imply concomitant combustion; because combustion properly so + called cannot take place without disengagement of caloric and light. + Before combustion can take place, it is necessary that the base of oxygen + gas should have greater affinity to the combustible body than it has to + caloric; and this elective attraction, to use Bergman's expression, can + only take place at a certain degree of temperature which is different for + each combustible substance; hence the necessity of giving the first motion + or beginning to every combustion by the approach of a heated body. This + necessity of heating any body we mean to burn depends upon certain + considerations which have not hitherto been attended to by any natural + philosopher, for which reason I shall enlarge a little upon the subject in + this place: + </p> + <p> + "Nature is at present in a state of equilibrium, which cannot have been + attained until all the spontaneous combustions or oxygenations possible in + an ordinary degree of temperature had taken place.... To illustrate this + abstract view of the matter by example: Let us suppose the usual + temperature of the earth a little changed, and it is raised only to the + degree of boiling water; it is evident that in this case phosphorus, which + is combustible in a considerably lower degree of temperature, would no + longer exist in nature in its pure and simple state, but would always be + procured in its acid or oxygenated state, and its radical would become one + of the substances unknown to chemistry. By gradually increasing the + temperature of the earth, the same circumstance would successively happen + to all the bodies capable of combustion; and, at the last, every possible + combustion having taken place, there would no longer exist any combustible + body whatever, and every substance susceptible of the operation would be + oxygenated and consequently incombustible. + </p> + <p> + "There cannot, therefore, exist, as far as relates to us, any combustible + body but such as are non-combustible at the ordinary temperature of the + earth, or, what is the same thing in other words, that it is essential to + the nature of every combustible body not to possess the property of + combustion unless heated, or raised to a degree of temperature at which + its combustion naturally takes place. When this degree is once produced, + combustion commences, and the caloric which is disengaged by the + decomposition of the oxygen gas keeps up the temperature which is + necessary for continuing combustion. When this is not the case—that + is, when the disengaged caloric is not sufficient for keeping up the + necessary temperature—the combustion ceases. This circumstance is + expressed in the common language by saying that a body burns ill or with + difficulty."(10) + </p> + <p> + It needed the genius of such a man as Lavoisier to complete the refutation + of the false but firmly grounded phlogiston theory, and against such a + book as his Elements of Chemistry the feeble weapons of the supporters of + the phlogiston theory were hurled in vain. + </p> + <p> + But while chemists, as a class, had become converts to the new chemistry + before the end of the century, one man, Dr. Priestley, whose work had done + so much to found it, remained unconverted. In this, as in all his + life-work, he showed himself to be a most remarkable man. Davy said of + him, a generation later, that no other person ever discovered so many new + and curious substances as he; yet to the last he was only an amateur in + science, his profession, as we know, being the ministry. There is hardly + another case in history of a man not a specialist in science accomplishing + so much in original research as did this chemist, physiologist, + electrician; the mathematician, logician, and moralist; the theologian, + mental philosopher, and political economist. He took all knowledge for his + field; but how he found time for his numberless researches and + multifarious writings, along with his every-day duties, must ever remain a + mystery to ordinary mortals. + </p> + <p> + That this marvellously receptive, flexible mind should have refused + acceptance to the clearly logical doctrines of the new chemistry seems + equally inexplicable. But so it was. To the very last, after all his + friends had capitulated, Priestley kept up the fight. From America he sent + out his last defy to the enemy, in 1800, in a brochure entitled "The + Doctrine of Phlogiston Upheld," etc. In the mind of its author it was + little less than a paean of victory; but all the world beside knew that it + was the swan-song of the doctrine of phlogiston. Despite the defiance of + this single warrior the battle was really lost and won, and as the century + closed "antiphlogistic" chemistry had practical possession of the field. + </p> + <p> + <a name="link2H_4_0004" id="link2H_4_0004"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + III. CHEMISTRY SINCE THE TIME OF DALTON + </h2> + <h3> + JOHN DALTON AND THE ATOMIC THEORY + </h3> + <p> + Small beginnings as have great endings—sometimes. As a case in + point, note what came of the small, original effort of a self-trained + back-country Quaker youth named John Dalton, who along towards the close + of the eighteenth century became interested in the weather, and was led to + construct and use a crude water-gauge to test the amount of the rainfall. + The simple experiments thus inaugurated led to no fewer than two hundred + thousand recorded observations regarding the weather, which formed the + basis for some of the most epochal discoveries in meteorology, as we have + seen. But this was only a beginning. The simple rain-gauge pointed the way + to the most important generalization of the nineteenth century in a field + of science with which, to the casual observer, it might seem to have no + alliance whatever. The wonderful theory of atoms, on which the whole + gigantic structure of modern chemistry is founded, was the logical + outgrowth, in the mind of John Dalton, of those early studies in + meteorology. + </p> + <p> + The way it happened was this: From studying the rainfall, Dalton turned + naturally to the complementary process of evaporation. He was soon led to + believe that vapor exists, in the atmosphere as an independent gas. But + since two bodies cannot occupy the same space at the same time, this + implies that the various atmospheric gases are really composed of discrete + particles. These ultimate particles are so small that we cannot see them—cannot, + indeed, more than vaguely imagine them—yet each particle of vapor, + for example, is just as much a portion of water as if it were a drop out + of the ocean, or, for that matter, the ocean itself. But, again, water is + a compound substance, for it may be separated, as Cavendish has shown, + into the two elementary substances hydrogen and oxygen. Hence the atom of + water must be composed of two lesser atoms joined together. Imagine an + atom of hydrogen and one of oxygen. Unite them, and we have an atom of + water; sever them, and the water no longer exists; but whether united or + separate the atoms of hydrogen and of oxygen remain hydrogen and oxygen + and nothing else. Differently mixed together or united, atoms produce + different gross substances; but the elementary atoms never change their + chemical nature—their distinct personality. + </p> + <p> + It was about the year 1803 that Dalton first gained a full grasp of the + conception of the chemical atom. At once he saw that the hypothesis, if + true, furnished a marvellous key to secrets of matter hitherto insoluble—questions + relating to the relative proportions of the atoms themselves. It is known, + for example, that a certain bulk of hydrogen gas unites with a certain + bulk of oxygen gas to form water. If it be true that this combination + consists essentially of the union of atoms one with another (each single + atom of hydrogen united to a single atom of oxygen), then the relative + weights of the original masses of hydrogen and of oxygen must be also the + relative weights of each of their respective atoms. If one pound of + hydrogen unites with five and one-half pounds of oxygen (as, according to + Dalton's experiments, it did), then the weight of the oxygen atom must be + five and one-half times that of the hydrogen atom. Other compounds may + plainly be tested in the same way. Dalton made numerous tests before he + published his theory. He found that hydrogen enters into compounds in + smaller proportions than any other element known to him, and so, for + convenience, determined to take the weight of the hydrogen atom as unity. + The atomic weight of oxygen then becomes (as given in Dalton's first table + of 1803) 5.5; that of water (hydrogen plus oxygen) being of course 6.5. + The atomic weights of about a score of substances are given in Dalton's + first paper, which was read before the Literary and Philosophical Society + of Manchester, October 21, 1803. I wonder if Dalton himself, great and + acute intellect though he had, suspected, when he read that paper, that he + was inaugurating one of the most fertile movements ever entered on in the + whole history of science? + </p> + <p> + Be that as it may, it is certain enough that Dalton's contemporaries were + at first little impressed with the novel atomic theory. Just at this time, + as it chanced, a dispute was waging in the field of chemistry regarding a + matter of empirical fact which must necessarily be settled before such a + theory as that of Dalton could even hope for a bearing. This was the + question whether or not chemical elements unite with one another always in + definite proportions. Berthollet, the great co-worker with Lavoisier, and + now the most authoritative of living chemists, contended that substances + combine in almost indefinitely graded proportions between fixed extremes. + He held that solution is really a form of chemical combination—a + position which, if accepted, left no room for argument. + </p> + <p> + But this contention of the master was most actively disputed, in + particular by Louis Joseph Proust, and all chemists of repute were obliged + to take sides with one or the other. For a time the authority of + Berthollet held out against the facts, but at last accumulated evidence + told for Proust and his followers, and towards the close of the first + decade of our century it came to be generally conceded that chemical + elements combine with one another in fixed and definite proportions. + </p> + <p> + More than that. As the analysts were led to weigh carefully the quantities + of combining elements, it was observed that the proportions are not only + definite, but that they bear a very curious relation to one another. If + element A combines with two different proportions of element B to form two + compounds, it appears that the weight of the larger quantity of B is an + exact multiple of that of the smaller quantity. This curious relation was + noticed by Dr. Wollaston, one of the most accurate of observers, and a + little later it was confirmed by Johan Jakob Berzelius, the great Swedish + chemist, who was to be a dominating influence in the chemical world for a + generation to come. But this combination of elements in numerical + proportions was exactly what Dalton had noticed as early as 1802, and what + bad led him directly to the atomic weights. So the confirmation of this + essential point by chemists of such authority gave the strongest + confirmation to the atomic theory. + </p> + <p> + During these same years the rising authority of the French chemical world, + Joseph Louis Gay-Lussac, was conducting experiments with gases, which he + had undertaken at first in conjunction with Humboldt, but which later on + were conducted independently. In 1809, the next year after the publication + of the first volume of Dalton's New System of Chemical Philosophy, + Gay-Lussac published the results of his observations, and among other + things brought out the remarkable fact that gases, under the same + conditions as to temperature and pressure, combine always in definite + numerical proportions as to volume. Exactly two volumes of hydrogen, for + example, combine with one volume of oxygen to form water. Moreover, the + resulting compound gas always bears a simple relation to the combining + volumes. In the case just cited, the union of two volumes of hydrogen and + one of oxygen results in precisely two volumes of water vapor. + </p> + <p> + Naturally enough, the champions of the atomic theory seized upon these + observations of Gay-Lussac as lending strong support to their hypothesis—all + of them, that is, but the curiously self-reliant and self-sufficient + author of the atomic theory himself, who declined to accept the + observations of the French chemist as valid. Yet the observations of + Gay-Lussac were correct, as countless chemists since then have + demonstrated anew, and his theory of combination by volumes became one of + the foundation-stones of the atomic theory, despite the opposition of the + author of that theory. + </p> + <p> + The true explanation of Gay-Lussac's law of combination by volumes was + thought out almost immediately by an Italian savant, Amadeo, Avogadro, and + expressed in terms of the atomic theory. The fact must be, said Avogadro, + that under similar physical conditions every form of gas contains exactly + the same number of ultimate particles in a given volume. Each of these + ultimate physical particles may be composed of two or more atoms (as in + the case of water vapor), but such a compound atom conducts itself as if + it were a simple and indivisible atom, as regards the amount of space that + separates it from its fellows under given conditions of pressure and + temperature. The compound atom, composed of two or more elementary atoms, + Avogadro proposed to distinguish, for purposes of convenience, by the name + molecule. It is to the molecule, considered as the unit of physical + structure, that Avogadro's law applies. + </p> + <p> + This vastly important distinction between atoms and molecules, implied in + the law just expressed, was published in 1811. Four years later, the + famous French physicist Ampere outlined a similar theory, and utilized the + law in his mathematical calculations. And with that the law of Avogadro + dropped out of sight for a full generation. Little suspecting that it was + the very key to the inner mysteries of the atoms for which they were + seeking, the chemists of the time cast it aside, and let it fade from the + memory of their science. + </p> + <p> + This, however, was not strange, for of course the law of Avogadro is based + on the atomic theory, and in 1811 the atomic theory was itself still being + weighed in the balance. The law of multiple proportions found general + acceptance as an empirical fact; but many of the leading lights of + chemistry still looked askance at Dalton's explanation of this law. Thus + Wollaston, though from the first he inclined to acceptance of the + Daltonian view, cautiously suggested that it would be well to use the + non-committal word "equivalent" instead of "atom"; and Davy, for a similar + reason, in his book of 1812, speaks only of "proportions," binding himself + to no theory as to what might be the nature of these proportions. + </p> + <p> + At least two great chemists of the time, however, adopted the atomic view + with less reservation. One of these was Thomas Thomson, professor at + Edinburgh, who, in 1807, had given an outline of Dalton's theory in a + widely circulated book, which first brought the theory to the general + attention of the chemical world. The other and even more noted advocate of + the atomic theory was Johan Jakob Berzelius. This great Swedish chemist at + once set to work to put the atomic theory to such tests as might be + applied in the laboratory. He was an analyst of the utmost skill, and for + years he devoted himself to the determination of the combining weights, + "equivalents" or "proportions," of the different elements. These + determinations, in so far as they were accurately made, were simple + expressions of empirical facts, independent of any theory; but gradually + it became more and more plain that these facts all harmonize with the + atomic theory of Dalton. So by common consent the proportionate combining + weights of the elements came to be known as atomic weights—the name + Dalton had given them from the first—and the tangible conception of + the chemical atom as a body of definite constitution and weight gained + steadily in favor. + </p> + <p> + From the outset the idea had had the utmost tangibility in the mind of + Dalton. He had all along represented the different atoms by geometrical + symbols—as a circle for oxygen, a circle enclosing a dot for + hydrogen, and the like—and had represented compounds by placing + these symbols of the elements in juxtaposition. Berzelius proposed to + improve upon this method by substituting for the geometrical symbol the + initial of the Latin name of the element represented—O for oxygen, H + for hydrogen, and so on—a numerical coefficient to follow the letter + as an indication of the number of atoms present in any given compound. + This simple system soon gained general acceptance, and with slight + modifications it is still universally employed. Every school-boy now is + aware that H2O is the chemical way of expressing the union of two atoms of + hydrogen with one of oxygen to form a molecule of water. But such a + formula would have had no meaning for the wisest chemist before the day of + Berzelius. + </p> + <p> + The universal fame of the great Swedish authority served to give general + currency to his symbols and atomic weights, and the new point of view thus + developed led presently to two important discoveries which removed the + last lingering doubts as to the validity of the atomic theory. In 1819 two + French physicists, Dulong and Petit, while experimenting with heat, + discovered that the specific heats of solids (that is to say, the amount + of heat required to raise the temperature of a given mass to a given + degree) vary inversely as their atomic weights. In the same year Eilhard + Mitscherlich, a German investigator, observed that compounds having the + same number of atoms to the molecule are disposed to form the same angles + of crystallization—a property which he called isomorphism. + </p> + <p> + Here, then, were two utterly novel and independent sets of empirical facts + which harmonize strangely with the supposition that substances are + composed of chemical atoms of a determinate weight. This surely could not + be coincidence—it tells of law. And so as soon as the claims of + Dulong and Petit and of Mitscherlich had been substantiated by other + observers, the laws of the specific heat of atoms, and of isomorphism, + took their place as new levers of chemical science. With the aid of these + new tools an impregnable breastwork of facts was soon piled about the + atomic theory. And John Dalton, the author of that theory, plain, + provincial Quaker, working on to the end in semi-retirement, became known + to all the world and for all time as a master of masters. + </p> + <p> + HUMPHRY DAVY AND ELECTRO-CHEMISTRY + </p> + <p> + During those early years of the nineteenth century, when Dalton was + grinding away at chemical fact and theory in his obscure Manchester + laboratory, another Englishman held the attention of the chemical world + with a series of the most brilliant and widely heralded researches. This + was Humphry Davy, a young man who had conic to London in 1801, at the + instance of Count Rumford, to assume the chair of chemical philosophy in + the Royal Institution, which the famous American had just founded. + </p> + <p> + Here, under Davy's direction, the largest voltaic battery yet constructed + had been put in operation, and with its aid the brilliant young + experimenter was expected almost to perform miracles. And indeed he + scarcely disappointed the expectation, for with the aid of his battery he + transformed so familiar a substance as common potash into a metal which + was not only so light that it floated on water, but possessed the + seemingly miraculous property of bursting into flames as soon as it came + in contact with that fire-quenching liquid. If this were not a miracle, it + had for the popular eye all the appearance of the miraculous. + </p> + <p> + What Davy really had done was to decompose the potash, which hitherto had + been supposed to be elementary, liberating its oxygen, and thus isolating + its metallic base, which he named potassium. The same thing was done with + soda, and the closely similar metal sodium was discovered—metals of + a unique type, possessed of a strange avidity for oxygen, and capable of + seizing on it even when it is bound up in the molecules of water. + Considered as mere curiosities, these discoveries were interesting, but + aside from that they were of great theoretical importance, because they + showed the compound nature of some familiar chemicals that had been + regarded as elements. Several other elementary earths met the same fate + when subjected to the electrical influence; the metals barium, calcium, + and strontium being thus discovered. Thereafter Davy always referred to + the supposed elementary substances (including oxygen, hydrogen, and the + rest) as "unde-compounded" bodies. These resist all present efforts to + decompose them, but how can one know what might not happen were they + subjected to an influence, perhaps some day to be discovered, which + exceeds the battery in power as the battery exceeds the blowpipe? + </p> + <p> + Another and even more important theoretical result that flowed from Davy's + experiments during this first decade of the century was the proof that no + elementary substances other than hydrogen and oxygen are produced when + pure water is decomposed by the electric current. It was early noticed by + Davy and others that when a strong current is passed through water, + alkalies appear at one pole of the battery and acids at the other, and + this though the water used were absolutely pure. This seemingly told of + the creation of elements—a transmutation but one step removed from + the creation of matter itself—under the influence of the new + "force." It was one of Davy's greatest triumphs to prove, in the series of + experiments recorded in his famous Bakerian lecture of 1806, that the + alleged creation of elements did not take place, the substances found at + the poles of the battery having been dissolved from the walls of the + vessels in which the water experimented upon had been placed. Thus the + same implement which had served to give a certain philosophical warrant to + the fading dreams of alchemy banished those dreams peremptorily from the + domain of present science. + </p> + <p> + "As early as 1800," writes Davy, "I had found that when separate portions + of distilled water, filling two glass tubes, connected by moist bladders, + or any moist animal or vegetable substances, were submitted to the + electrical action of the pile of Volta by means of gold wires, a + nitro-muriatic solution of gold appeared in the tube containing the + positive wire, or the wire transmitting the electricity, and a solution of + soda in the opposite tube; but I soon ascertained that the muriatic acid + owed its existence to the animal or vegetable matters employed; for when + the same fibres of cotton were made use of in successive experiments, and + washed after every process in a weak solution of nitric acid, the water in + the apparatus containing them, though acted on for a great length of time + with a very strong power, at last produced no effects upon nitrate of + silver. + </p> + <p> + "In cases when I had procured much soda, the glass at its point of contact + with the wire seemed considerably corroded; and I was confirmed in my idea + of referring the production of the alkali principally to this source, by + finding that no fixed saline matter could be obtained by electrifying + distilled water in a single agate cup from two points of platina with the + Voltaic battery. + </p> + <p> + "Mr. Sylvester, however, in a paper published in Mr. Nicholson's journal + for last August, states that though no fixed alkali or muriatic acid + appears when a single vessel is employed, yet that they are both formed + when two vessels are used. And to do away with all objections with regard + to vegetable substances or glass, he conducted his process in a vessel + made of baked tobacco-pipe clay inserted in a crucible of platina. I have + no doubt of the correctness of his results; but the conclusion appears + objectionable. He conceives, that he obtained fixed alkali, because the + fluid after being heated and evaporated left a matter that tinged turmeric + brown, which would have happened had it been lime, a substance that exists + in considerable quantities in all pipe-clay; and even allowing the + presence of fixed alkali, the materials employed for the manufacture of + tobacco-pipes are not at all such as to exclude the combinations of this + substance. + </p> + <p> + "I resumed the inquiry; I procured small cylindrical cups of agate of the + capacity of about one-quarter of a cubic inch each. They were boiled for + some hours in distilled water, and a piece of very white and transparent + amianthus that had been treated in the same way was made then to connect + together; they were filled with distilled water and exposed by means of + two platina wires to a current of electricity, from one hundred and fifty + pairs of plates of copper and zinc four inches square, made active by + means of solution of alum. After forty-eight hours the process was + examined: Paper tinged with litmus plunged into the tube containing the + transmitting or positive wire was immediately strongly reddened. Paper + colored by turmeric introduced into the other tube had its color much + deepened; the acid matter gave a very slight degree of turgidness to + solution of nitrate of soda. The fluid that affected turmeric retained + this property after being strongly boiled; and it appeared more vivid as + the quantity became reduced by evaporation; carbonate of ammonia was mixed + with it, and the whole dried and exposed to a strong heat; a minute + quantity of white matter remained, which, as far as my examinations could + go, had the properties of carbonate of soda. I compared it with similar + minute portions of the pure carbonates of potash, and similar minute + portions of the pure carbonates of potash and soda. It was not so + deliquescent as the former of these bodies, and it formed a salt with + nitric acid, which, like nitrate of soda, soon attracted moisture from a + damp atmosphere and became fluid. + </p> + <p> + "This result was unexpected, but it was far from convincing me that the + substances which were obtained were generated. In a similar process with + glass tubes, carried on under exactly the same circumstances and for the + same time, I obtained a quantity of alkali which must have been more than + twenty times greater, but no traces of muriatic acid. There was much + probability that the agate contained some minute portion of saline matter, + not easily detected by chemical analysis, either in combination or + intimate cohesion in its pores. To determine this, I repeated this a + second, a third, and a fourth time. In the second experiment turbidness + was still produced by a solution of nitrate of silver in the tube + containing the acid, but it was less distinct; in the third process it was + barely perceptible; and in the fourth process the two fluids remained + perfectly clear after the mixture. The quantity of alkaline matter + diminished in every operation; and in the last process, though the battery + had been kept in great activity for three days, the fluid possessed, in a + very slight degree, only the power of acting on paper tinged with + turmeric; but its alkaline property was very sensible to litmus paper + slightly reddened, which is a much more delicate test; and after + evaporation and the process by carbonate of ammonia, a barely perceptible + quantity of fixed alkali was still left. The acid matter in the other tube + was abundant; its taste was sour; it smelled like water over which large + quantities of nitrous gas have been long kept; it did not effect solution + of muriate of barytes; and a drop of it placed upon a polished plate of + silver left, after evaporation, a black stain, precisely similar to that + produced by extremely diluted nitrous acid. + </p> + <p> + "After these results I could no longer doubt that some saline matter + existing in the agate tubes had been the source of the acid matter capable + of precipitating nitrate of silver and much of the alkali. Four additional + repetitions of the process, however, convinced me that there was likewise + some other cause for the presence of this last substance; for it continued + to appear to the last in quantities sufficiently distinguishable, and + apparently equal in every case. I had used every precaution, I had + included the tube in glass vessels out of the reach of the circulating + air; all the acting materials had been repeatedly washed with distilled + water; and no part of them in contact with the fluid had been touched by + the fingers. + </p> + <p> + "The only substance that I could now conceive as furnishing the fixed + alkali was the water itself. This water appeared pure by the tests of + nitrate of silver and muriate of barytes; but potash of soda, as is well + known, rises in small quantities in rapid distillation; and the New River + water which I made use of contains animal and vegetable impurities, which + it was easy to conceive might furnish neutral salts capable of being + carried over in vivid ebullition."(1) Further experiment proved the + correctness of this inference, and the last doubt as to the origin of the + puzzling chemical was dispelled. + </p> + <p> + Though the presence of the alkalies and acids in the water was explained, + however, their respective migrations to the negative and positive poles of + the battery remained to be accounted for. Davy's classical explanation + assumed that different elements differ among themselves as to their + electrical properties, some being positively, others negatively, + electrified. Electricity and "chemical affinity," he said, apparently are + manifestations of the same force, acting in the one case on masses, in the + other on particles. Electro-positive particles unite with electro-negative + particles to form chemical compounds, in virtue of the familiar principle + that opposite electricities attract one another. When compounds are + decomposed by the battery, this mutual attraction is overcome by the + stronger attraction of the poles of the battery itself. + </p> + <p> + This theory of binary composition of all chemical compounds, through the + union of electro-positive and electro-negative atoms or molecules, was + extended by Berzelius, and made the basis of his famous system of + theoretical chemistry. This theory held that all inorganic compounds, + however complex their composition, are essentially composed of such binary + combinations. For many years this view enjoyed almost undisputed sway. It + received what seemed strong confirmation when Faraday showed the definite + connection between the amount of electricity employed and the amount of + decomposition produced in the so-called electrolyte. But its claims were + really much too comprehensive, as subsequent discoveries proved. + </p> + <p> + ORGANIC CHEMISTRY AND THE IDEA OF THE MOLECULE + </p> + <p> + When Berzelius first promulgated his binary theory he was careful to + restrict its unmodified application to the compounds of the inorganic + world. At that time, and for a long time thereafter, it was supposed that + substances of organic nature had some properties that kept them aloof from + the domain of inorganic chemistry. It was little doubted that a so-called + "vital force" operated here, replacing or modifying the action of ordinary + "chemical affinity." It was, indeed, admitted that organic compounds are + composed of familiar elements—chiefly carbon, oxygen, hydrogen, and + nitrogen; but these elements were supposed to be united in ways that could + not be imitated in the domain of the non-living. It was regarded almost as + an axiom of chemistry that no organic compound whatever could be put + together from its elements—synthesized—in the laboratory. To + effect the synthesis of even the simplest organic compound, it was thought + that the "vital force" must be in operation. + </p> + <p> + Therefore a veritable sensation was created in the chemical world when, in + the year 1828, it was announced that the young German chemist, Friedrich + Wohler, formerly pupil of Berzelius, and already known as a coming master, + had actually synthesized the well-known organic product urea in his + laboratory at Sacrow. The "exception which proves the rule" is something + never heard of in the domain of logical science. Natural law knows no + exceptions. So the synthesis of a single organic compound sufficed at a + blow to break down the chemical barrier which the imagination of the + fathers of the science had erected between animate and inanimate nature. + Thenceforth the philosophical chemist would regard the plant and animal + organisms as chemical laboratories in which conditions are peculiarly + favorable for building up complex compounds of a few familiar elements, + under the operation of universal chemical laws. The chimera "vital force" + could no longer gain recognition in the domain of chemistry. + </p> + <p> + Now a wave of interest in organic chemistry swept over the chemical world, + and soon the study of carbon compounds became as much the fashion as + electrochemistry had been in the, preceding generation. + </p> + <p> + Foremost among the workers who rendered this epoch of organic chemistry + memorable were Justus Liebig in Germany and Jean Baptiste Andre Dumas in + France, and their respective pupils, Charles Frederic Gerhardt and + Augustus Laurent. Wohler, too, must be named in the same breath, as also + must Louis Pasteur, who, though somewhat younger than the others, came + upon the scene in time to take chief part in the most important of the + controversies that grew out of their labors. + </p> + <p> + Several years earlier than this the way had been paved for the study of + organic substances by Gay-Lussac's discovery, made in 1815, that a certain + compound of carbon and nitrogen, which he named cyanogen, has a peculiar + degree of stability which enables it to retain its identity and enter into + chemical relations after the manner of a simple body. A year later Ampere + discovered that nitrogen and hydrogen, when combined in certain + proportions to form what he called ammonium, have the same property. + Berzelius had seized upon this discovery of the compound radical, as it + was called, because it seemed to lend aid to his dualistic theory. He + conceived the idea that all organic compounds are binary unions of various + compound radicals with an atom of oxygen, announcing this theory in 1818. + Ten years later, Liebig and Wohler undertook a joint investigation which + resulted in proving that compound radicals are indeed very abundant among + organic substances. Thus the theory of Berzelius seemed to be + substantiated, and organic chemistry came to be defined as the chemistry + of compound radicals. + </p> + <p> + But even in the day of its seeming triumph the dualistic theory was + destined to receive a rude shock. This came about through the + investigations of Dumas, who proved that in a certain organic substance an + atom of hydrogen may be removed and an atom of chlorine substituted in its + place without destroying the integrity of the original compound—much + as a child might substitute one block for another in its play-house. Such + a substitution would be quite consistent with the dualistic theory, were + it not for the very essential fact that hydrogen is a powerfully + electro-positive element, while chlorine is as strongly electro-negative. + Hence the compound radical which united successively with these two + elements must itself be at one time electro-positive, at another + electro-negative—a seeming inconsistency which threw the entire + Berzelian theory into disfavor. + </p> + <p> + In its place there was elaborated, chiefly through the efforts of Laurent + and Gerhardt, a conception of the molecule as a unitary structure, built + up through the aggregation of various atoms, in accordance with "elective + affinities" whose nature is not yet understood A doctrine of "nuclei" and + a doctrine of "types" of molecular structure were much exploited, and, + like the doctrine of compound radicals, became useful as aids to memory + and guides for the analyst, indicating some of the plans of molecular + construction, though by no means penetrating the mysteries of chemical + affinity. They are classifications rather than explanations of chemical + unions. But at least they served an important purpose in giving + definiteness to the idea of a molecular structure built of atoms as the + basis of all substances. Now at last the word molecule came to have a + distinct meaning, as distinct from "atom," in the minds of the generality + of chemists, as it had had for Avogadro a third of a century before. + Avogadro's hypothesis that there are equal numbers of these molecules in + equal volumes of gases, under fixed conditions, was revived by Gerhardt, + and a little later, under the championship of Cannizzaro, was exalted to + the plane of a fixed law. Thenceforth the conception of the molecule was + to be as dominant a thought in chemistry as the idea of the atom had + become in a previous epoch. + </p> + <p> + CHEMICAL AFFINITY + </p> + <p> + Of course the atom itself was in no sense displaced, but Avogadro's law + soon made it plain that the atom had often usurped territory that did not + really belong to it. In many cases the chemists had supposed themselves + dealing with atoms as units where the true unit was the molecule. In the + case of elementary gases, such as hydrogen and oxygen, for example, the + law of equal numbers of molecules in equal spaces made it clear that the + atoms do not exist isolated, as had been supposed. Since two volumes of + hydrogen unite with one volume of oxygen to form two volumes of water + vapor, the simplest mathematics show, in the light of Avogadro's law, not + only that each molecule of water must contain two hydrogen atoms (a point + previously in dispute), but that the original molecules of hydrogen and + oxygen must have been composed in each case of two atoms—-else how + could one volume of oxygen supply an atom for every molecule of two + volumes of water? + </p> + <p> + What, then, does this imply? Why, that the elementary atom has an avidity + for other atoms, a longing for companionship, an "affinity"—call it + what you will—which is bound to be satisfied if other atoms are in + the neighborhood. Placed solely among atoms of its own kind, the oxygen + atom seizes on a fellow oxygen atom, and in all their mad dancings these + two mates cling together—possibly revolving about each other in + miniature planetary orbits. Precisely the same thing occurs among the + hydrogen atoms. But now suppose the various pairs of oxygen atoms come + near other pairs of hydrogen atoms (under proper conditions which need not + detain us here), then each oxygen atom loses its attachment for its + fellow, and flings itself madly into the circuit of one of the hydrogen + couplets, and—presto!—there are only two molecules for every + three there were before, and free oxygen and hydrogen have become water. + The whole process, stated in chemical phraseology, is summed up in the + statement that under the given conditions the oxygen atoms had a greater + affinity for the hydrogen atoms than for one another. + </p> + <p> + As chemists studied the actions of various kinds of atoms, in regard to + their unions with one another to form molecules, it gradually dawned upon + them that not all elements are satisfied with the same number of + companions. Some elements ask only one, and refuse to take more; while + others link themselves, when occasion offers, with two, three, four, or + more. Thus we saw that oxygen forsook a single atom of its own kind and + linked itself with two atoms of hydrogen. Clearly, then, the oxygen atom, + like a creature with two hands, is able to clutch two other atoms. But we + have no proof that under any circumstances it could hold more than two. + Its affinities seem satisfied when it has two bonds. But, on the other + hand, the atom of nitrogen is able to hold three atoms of hydrogen, and + does so in the molecule of ammonium (NH3); while the carbon atom can hold + four atoms of hydrogen or two atoms of oxygen. + </p> + <p> + Evidently, then, one atom is not always equivalent to another atom of a + different kind in combining powers. A recognition of this fact by + Frankland about 1852, and its further investigation by others (notably A. + Kekule and A. S. Couper), led to the introduction of the word equivalent + into chemical terminology in a new sense, and in particular to an + understanding of the affinities or "valency" of different elements, which + proved of the most fundamental importance. Thus it was shown that, of the + four elements that enter most prominently into organic compounds, hydrogen + can link itself with only a single bond to any other element—it has, + so to speak, but a single hand with which to grasp—while oxygen has + capacity for two bonds, nitrogen for three (possibly for five), and carbon + for four. The words monovalent, divalent, trivalent, tretrava-lent, etc., + were coined to express this most important fact, and the various elements + came to be known as monads, diads, triads, etc. Just why different + elements should differ thus in valency no one as yet knows; it is an + empirical fact that they do. And once the nature of any element has been + determined as regards its valency, a most important insight into the + possible behavior of that element has been secured. Thus a consideration + of the fact that hydrogen is monovalent, while oxygen is divalent, makes + it plain that we must expect to find no more than three compounds of these + two elements—namely, H—O—(written HO by the chemist, and + called hydroxyl); H—O—H (H2O, or water), and H—O—O—H + (H2O2, or hydrogen peroxide). It will be observed that in the first of + these compounds the atom of oxygen stands, so to speak, with one of its + hands free, eagerly reaching out, therefore, for another companion, and + hence, in the language of chemistry, forming an unstable compound. Again, + in the third compound, though all hands are clasped, yet one pair links + oxygen with oxygen; and this also must be an unstable union, since the + avidity of an atom for its own kind is relatively weak. Thus the + well-known properties of hydrogen peroxide are explained, its easy + decomposition, and the eagerness with which it seizes upon the elements of + other compounds. + </p> + <p> + But the molecule of water, on the other hand, has its atoms arranged in a + state of stable equilibrium, all their affinities being satisfied. Each + hydrogen atom has satisfied its own affinity by clutching the oxygen atom; + and the oxygen atom has both its bonds satisfied by clutching back at the + two hydrogen atoms. Therefore the trio, linked in this close bond, have no + tendency to reach out for any other companion, nor, indeed, any power to + hold another should it thrust itself upon them. They form a "stable" + compound, which under all ordinary circumstances will retain its identity + as a molecule of water, even though the physical mass of which it is a + part changes its condition from a solid to a gas from ice to vapor. + </p> + <p> + But a consideration of this condition of stable equilibrium in the + molecule at once suggests a new question: How can an aggregation of atoms, + having all their affinities satisfied, take any further part in chemical + reactions? Seemingly such a molecule, whatever its physical properties, + must be chemically inert, incapable of any atomic readjustments. And so in + point of fact it is, so long as its component atoms cling to one another + unremittingly. But this, it appears, is precisely what the atoms are + little prone to do. It seems that they are fickle to the last degree in + their individual attachments, and are as prone to break away from bondage + as they are to enter into it. Thus the oxygen atom which has just flung + itself into the circuit of two hydrogen atoms, the next moment flings + itself free again and seeks new companions. It is for all the world like + the incessant change of partners in a rollicking dance. This incessant + dissolution and reformation of molecules in a substance which as a whole + remains apparently unchanged was first fully appreciated by Ste.-Claire + Deville, and by him named dissociation. It is a process which goes on much + more actively in some compounds than in others, and very much more + actively under some physical conditions (such as increase of temperature) + than under others. But apparently no substances at ordinary temperatures, + and no temperature above the absolute zero, are absolutely free from its + disturbing influence. Hence it is that molecules having all the valency of + their atoms fully satisfied do not lose their chemical activity—since + each atom is momentarily free in the exchange of partners, and may seize + upon different atoms from its former partners, if those it prefers are at + hand. + </p> + <p> + While, however, an appreciation of this ceaseless activity of the atom is + essential to a proper understanding of its chemical efficiency, yet from + another point of view the "saturated" molecule—that is, the molecule + whose atoms have their valency all satisfied—may be thought of as a + relatively fixed or stable organism. Even though it may presently be torn + down, it is for the time being a completed structure; and a consideration + of the valency of its atoms gives the best clew that has hitherto been + obtainable as to the character of its architecture. How important this + matter of architecture of the molecule—of space relations of the + atoms—may be—was demonstrated as long ago as 1823, when Liebig + and Wohler proved, to the utter bewilderment of the chemical world, that + two substances may have precisely the same chemical constitution—the + same number and kind of atoms—and yet differ utterly in physical + properties. The word isomerism was coined by Berzelius to express this + anomalous condition of things, which seemed to negative the most + fundamental truths of chemistry. Naming the condition by no means + explained it, but the fact was made clear that something besides the mere + number and kind of atoms is important in the architecture of a molecule. + It became certain that atoms are not thrown together haphazard to build a + molecule, any more than bricks are thrown together at random to form a + house. + </p> + <p> + How delicate may be the gradations of architectural design in building a + molecule was well illustrated about 1850, when Pasteur discovered that + some carbon compounds—as certain sugars—can only be + distinguished from one another, when in solution, by the fact of their + twisting or polarizing a ray of light to the left or to the right, + respectively. But no inkling of an explanation of these strange variations + of molecular structure came until the discovery of the law of valency. + Then much of the mystery was cleared away; for it was plain that since + each atom in a molecule can hold to itself only a fixed number of other + atoms, complex molecules must have their atoms linked in definite chains + or groups. And it is equally plain that where the atoms are numerous, the + exact plan of grouping may sometimes be susceptible of change without + doing violence to the law of valency. It is in such cases that isomerism + is observed to occur. + </p> + <p> + By paying constant heed to this matter of the affinities, chemists are + able to make diagrammatic pictures of the plan of architecture of any + molecule whose composition is known. In the simple molecule of water + (H2O), for example, the two hydrogen atoms must have released each other + before they could join the oxygen, and the manner of linking must + apparently be that represented in the graphic formula H—O—H. + With molecules composed of a large number of atoms, such graphic + representation of the scheme of linking is of course increasingly + difficult, yet, with the affinities for a guide, it is always possible. Of + course no one supposes that such a formula, written in a single plane, can + possibly represent the true architecture of the molecule: it is at best + suggestive or diagrammatic rather than pictorial. Nevertheless, it affords + hints as to the structure of the molecule such as the fathers of chemistry + would not have thought it possible ever to attain. + </p> + <p> + PERIODICITY OF ATOMIC WEIGHTS + </p> + <p> + These utterly novel studies of molecular architecture may seem at first + sight to take from the atom much of its former prestige as the + all-important personage of the chemical world. Since so much depends upon + the mere position of the atoms, it may appear that comparatively little + depends upon the nature of the atoms themselves. But such a view is + incorrect, for on closer consideration it will appear that at no time has + the atom been seen to renounce its peculiar personality. Within certain + limits the character of a molecule may be altered by changing the + positions of its atoms (just as different buildings may be constructed of + the same bricks), but these limits are sharply defined, and it would be as + impossible to exceed them as it would be to build a stone building with + bricks. From first to last the brick remains a brick, whatever the style + of architecture it helps to construct; it never becomes a stone. And just + as closely does each atom retain its own peculiar properties, regardless + of its surroundings. + </p> + <p> + Thus, for example, the carbon atom may take part in the formation at one + time of a diamond, again of a piece of coal, and yet again of a particle + of sugar, of wood fibre, of animal tissue, or of a gas in the atmosphere; + but from first to last—from glass-cutting gem to intangible gas—there + is no demonstrable change whatever in any single property of the atom + itself. So far as we know, its size, its weight, its capacity for + vibration or rotation, and its inherent affinities, remain absolutely + unchanged throughout all these varying fortunes of position and + association. And the same thing is true of every atom of all of the + seventy-odd elementary substances with which the modern chemist is + acquainted. Every one appears always to maintain its unique integrity, + gaining nothing and losing nothing. + </p> + <p> + All this being true, it would seem as if the position of the Daltonian + atom as a primordial bit of matter, indestructible and non-transmutable, + had been put to the test by the chemistry of our century, and not found + wanting. Since those early days of the century when the electric battery + performed its miracles and seemingly reached its limitations in the hands + of Davy, many new elementary substances have been discovered, but no + single element has been displaced from its position as an undecomposable + body. Rather have the analyses of the chemist seemed to make it more and + more certain that all elementary atoms are in truth what John Herschel + called them, "manufactured articles"—primordial, changeless, + indestructible. + </p> + <p> + And yet, oddly enough, it has chanced that hand in hand with the + experiments leading to such a goal have gone other experiments arid + speculations of exactly the opposite tenor. In each generation there have + been chemists among the leaders of their science who have refused to admit + that the so-called elements are really elements at all in any final sense, + and who have sought eagerly for proof which might warrant their + scepticism. The first bit of evidence tending to support this view was + furnished by an English physician, Dr. William Prout, who in 1815 called + attention to a curious relation to be observed between the atomic weight + of the various elements. Accepting the figures given by the authorities of + the time (notably Thomson and Berzelius), it appeared that a strikingly + large proportion of the atomic weights were exact multiples of the weight + of hydrogen, and that others differed so slightly that errors of + observation might explain the discrepancy. Prout felt that it could not be + accidental, and he could think of no tenable explanation, unless it be + that the atoms of the various alleged elements are made up of different + fixed numbers of hydrogen atoms. Could it be that the one true element—the + one primal matter—is hydrogen, and that all other forms of matter + are but compounds of this original substance? + </p> + <p> + Prout advanced this startling idea at first tentatively, in an anonymous + publication; but afterwards he espoused it openly and urged its + tenability. Coming just after Davy's dissociation of some supposed + elements, the idea proved alluring, and for a time gained such popularity + that chemists were disposed to round out the observed atomic weights of + all elements into whole numbers. But presently renewed determinations of + the atomic weights seemed to discountenance this practice, and Prout's + alleged law fell into disrepute. It was revived, however, about 1840, by + Dumas, whose great authority secured it a respectful hearing, and whose + careful redetermination of the weight of carbon, making it exactly twelve + times that of hydrogen, aided the cause. + </p> + <p> + Subsequently Stas, the pupil of Dumas, undertook a long series of + determinations of atomic weights, with the expectation of confirming the + Proutian hypothesis. But his results seemed to disprove the hypothesis, + for the atomic weights of many elements differed from whole numbers by + more, it was thought, than the limits of error of the experiments. It was + noteworthy, however, that the confidence of Dumas was not shaken, though + he was led to modify the hypothesis, and, in accordance with previous + suggestions of Clark and of Marignac, to recognize as the primordial + element, not hydrogen itself, but an atom half the weight, or even + one-fourth the weight, of that of hydrogen, of which primordial atom the + hydrogen atom itself is compounded. But even in this modified form the + hypothesis found great opposition from experimental observers. + </p> + <p> + In 1864, however, a novel relation between the weights of the elements and + their other characteristics was called to the attention of chemists by + Professor John A. R. Newlands, of London, who had noticed that if the + elements are arranged serially in the numerical order of their atomic + weights, there is a curious recurrence of similar properties at intervals + of eight elements This so-called "law of octaves" attracted little + immediate attention, but the facts it connotes soon came under the + observation of other chemists, notably of Professors Gustav Hinrichs in + America, Dmitri Mendeleeff in Russia, and Lothar Meyer in Germany. + Mendeleeff gave the discovery fullest expression, explicating it in 1869, + under the title of "the periodic law." + </p> + <p> + Though this early exposition of what has since been admitted to be a most + important discovery was very fully outlined, the generality of chemists + gave it little heed till a decade or so later, when three new elements, + gallium, scandium, and germanium, were discovered, which, on being + analyzed, were quite unexpectedly found to fit into three gaps which + Mendeleeff had left in his periodic scale. In effect the periodic law had + enabled Mendeleeff to predicate the existence of the new elements years + before they were discovered. Surely a system that leads to such results is + no mere vagary. So very soon the periodic law took its place as one of the + most important generalizations of chemical science. + </p> + <p> + This law of periodicity was put forward as an expression of observed + relations independent of hypothesis; but of course the theoretical + bearings of these facts could not be overlooked. As Professor J. H. + Gladstone has said, it forces upon us "the conviction that the elements + are not separate bodies created without reference to one another, but that + they have been originally fashioned, or have been built up, from one + another, according to some general plan." It is but a short step from that + proposition to the Proutian hypothesis. + </p> + <p> + NEW WEAPONS—SPECTROSCOPE AND CAMERA + </p> + <p> + But the atomic weights are not alone in suggesting the compound nature of + the alleged elements. Evidence of a totally different kind has contributed + to the same end, from a source that could hardly have been imagined when + the Proutian hypothesis, was formulated, through the tradition of a novel + weapon to the armamentarium of the chemist—the spectroscope. The + perfection of this instrument, in the hands of two German scientists, + Gustav Robert Kirchhoff and Robert Wilhelm Bunsen, came about through the + investigation, towards the middle of the century, of the meaning of the + dark lines which had been observed in the solar spectrum by Fraunhofer as + early as 1815, and by Wollaston a decade earlier. It was suspected by + Stokes and by Fox Talbot in England, but first brought to demonstration by + Kirchhoff and Bunsen, that these lines, which were known to occupy + definite positions in the spectrum, are really indicative of particular + elementary substances. By means of the spectroscope, which is essentially + a magnifying lens attached to a prism of glass, it is possible to locate + the lines with great accuracy, and it was soon shown that here was a new + means of chemical analysis of the most exquisite delicacy. It was found, + for example, that the spectroscope could detect the presence of a quantity + of sodium so infinitesimal as the one two-hundred-thousandth of a grain. + But what was even more important, the spectroscope put no limit upon the + distance of location of the substance it tested, provided only that + sufficient light came from it. The experiments it recorded might be + performed in the sun, or in the most distant stars or nebulae; indeed, one + of the earliest feats of the instrument was to wrench from the sun the + secret of his chemical constitution. + </p> + <p> + To render the utility of the spectroscope complete, however, it was + necessary to link with it another new chemical agency—namely, + photography. This now familiar process is based on the property of light + to decompose certain unstable compounds of silver, and thus alter their + chemical composition. Davy and Wedgwood barely escaped the discovery of + the value of the photographic method early in the nineteenth century. + Their successors quite overlooked it until about 1826, when Louis J. M. + Daguerre, the French chemist, took the matter in hand, and after many + years of experimentation brought it to relative perfection in 1839, in + which year the famous daguerreotype first brought the matter to popular + attention. In the same year Mr. Fox Talbot read a paper on the subject + before the Royal Society, and soon afterwards the efforts of Herschel and + numerous other natural philosophers contributed to the advancement of the + new method. + </p> + <p> + In 1843 Dr. John W. Draper, the famous English-American chemist and + physiologist, showed that by photography the Fraunhofer lines in the solar + spectrum might be mapped with absolute accuracy; also proving that the + silvered film revealed many lines invisible to the unaided eye. The value + of this method of observation was recognized at once, and, as soon as the + spectroscope was perfected, the photographic method, in conjunction with + its use, became invaluable to the chemist. By this means comparisons of + spectra may be made with a degree of accuracy not otherwise obtainable; + and, in case of the stars, whole clusters of spectra may be placed on + record at a single observation. + </p> + <p> + As the examination of the sun and stars proceeded, chemists were amazed or + delighted, according to their various preconceptions, to witness the proof + that many familiar terrestrial elements are to be found in the celestial + bodies. But what perhaps surprised them most was to observe the enormous + preponderance in the sidereal bodies of the element hydrogen. Not only are + there vast quantities of this element in the sun's atmosphere, but some + other suns appeared to show hydrogen lines almost exclusively in their + spectra. Presently it appeared that the stars of which this is true are + those white stars, such as Sirius, which had been conjectured to be the + hottest; whereas stars that are only red-hot, like our sun, show also the + vapors of many other elements, including iron and other metals. + </p> + <p> + In 1878 Professor J. Norman Lockyer, in a paper before the Royal Society, + called attention to the possible significance of this series of + observations. He urged that the fact of the sun showing fewer elements + than are observed here on the cool earth, while stars much hotter than the + sun show chiefly one element, and that one hydrogen, the lightest of known + elements, seemed to give color to the possibility that our alleged + elements are really compounds, which at the temperature of the hottest + stars may be decomposed into hydrogen, the latter "element" itself being + also doubtless a compound, which might be resolved under yet more trying + conditions. + </p> + <p> + Here, then, was what might be termed direct experimental evidence for the + hypothesis of Prout. Unfortunately, however, it is evidence of a kind + which only a few experts are competent to discuss—so very delicate a + matter is the spectral analysis of the stars. What is still more + unfortunate, the experts do not agree among themselves as to the validity + of Professor Lockyer's conclusions. Some, like Professor Crookes, have + accepted them with acclaim, hailing Lockyer as "the Darwin of the + inorganic world," while others have sought a different explanation of the + facts he brings forward. As yet it cannot be said that the controversy has + been brought to final settlement. Still, it is hardly to be doubted that + now, since the periodic law has seemed to join hands with the + spectroscope, a belief in the compound nature of the so-called elements is + rapidly gaining ground among chemists. More and more general becomes the + belief that the Daltonian atom is really a compound radical, and that back + of the seeming diversity of the alleged elements is a single form of + primordial matter. Indeed, in very recent months, direct experimental + evidence for this view has at last come to hand, through the study of + radio-active substances. In a later chapter we shall have occasion to + inquire how this came about. + </p> + <p> + <a name="link2H_4_0005" id="link2H_4_0005"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + IV. ANATOMY AND PHYSIOLOGY IN THE EIGHTEENTH CENTURY + </h2> + <h3> + ALBRECHT VON HALLER + </h3> + <p> + An epoch in physiology was made in the eighteenth century by the genius + and efforts of Albrecht von Haller (1708-1777), of Berne, who is perhaps + as worthy of the title "The Great" as any philosopher who has been so + christened by his contemporaries since the time of Hippocrates. Celebrated + as a physician, he was proficient in various fields, being equally famed + in his own time as poet, botanist, and statesman, and dividing his + attention between art and science. + </p> + <p> + As a child Haller was so sickly that he was unable to amuse himself with + the sports and games common to boys of his age, and so passed most of his + time poring over books. When ten years of age he began writing poems in + Latin and German, and at fifteen entered the University of Tubingen. At + seventeen he wrote learned articles in opposition to certain accepted + doctrines, and at nineteen he received his degree of doctor. Soon after + this he visited England, where his zeal in dissecting brought him under + suspicion of grave-robbery, which suspicion made it expedient for him to + return to the Continent. After studying botany in Basel for some time he + made an extended botanical journey through Switzerland, finally settling + in his native city, Berne, as a practising physician. During this time he + did not neglect either poetry or botany, publishing anonymously a + collection of poems. + </p> + <p> + In 1736 he was called to Gottingen as professor of anatomy, surgery, + chemistry, and botany. During his labors in the university he never + neglected his literary work, sometimes living and sleeping for days and + nights together in his library, eating his meals while delving in his + books, and sleeping only when actually compelled to do so by fatigue. + During all this time he was in correspondence with savants from all over + the world, and it is said of him that he never left a letter of any kind + unanswered. + </p> + <p> + Haller's greatest contribution to medical science was his famous doctrine + of irritability, which has given him the name of "father of modern nervous + physiology," just as Harvey is called "the father of the modern physiology + of the blood." It has been said of this famous doctrine of irritability + that "it moved all the minds of the century—and not in the + departments of medicine alone—in a way of which we of the present + day have no satisfactory conception, unless we compare it with our modern + Darwinism."(1) + </p> + <p> + The principle of general irritability had been laid down by Francis + Glisson (1597-1677) from deductive studies, but Haller proved by + experiments along the line of inductive methods that this irritability was + not common to all "fibre as well as to the fluids of the body," but + something entirely special, and peculiar only to muscular substance. He + distinguished between irritability of muscles and sensibility of nerves. + In 1747 he gave as the three forces that produce muscular movements: + elasticity, or "dead nervous force"; irritability, or "innate nervous + force"; and nervous force in itself. And in 1752 he described one hundred + and ninety experiments for determining what parts of the body possess + "irritability"—that is, the property of contracting when stimulated. + His conclusion that this irritability exists in muscular substance alone + and is quite independent of the nerves proceeding to it aroused a + controversy that was never definitely settled until late in the nineteenth + century, when Haller's theory was found to be entirely correct. + </p> + <p> + It was in pursuit of experiments to establish his theory of irritability + that Haller made his chief discoveries in embryology and development. He + proved that in the process of incubation of the egg the first trace of the + heart of the chick shows itself in the thirty-eighth hour, and that the + first trace of red blood showed in the forty-first hour. By his + investigations upon the lower animals he attempted to confirm the theory + that since the creation of genus every individual is derived from a + preceding individual—the existing theory of preformation, in which + he believed, and which taught that "every individual is fully and + completely preformed in the germ, simply growing from microscopic to + visible proportions, without developing any new parts." + </p> + <p> + In physiology, besides his studies of the nervous system, Haller studied + the mechanism of respiration, refuting the teachings of Hamberger + (1697-1755), who maintained that the lungs contract independently. Haller, + however, in common with his contemporaries, failed utterly to understand + the true function of the lungs. The great physiologist's influence upon + practical medicine, while most profound, was largely indirect. He was a + theoretical rather than a practical physician, yet he is credited with + being the first physician to use the watch in counting the pulse. + </p> + <p> + BATTISTA MORGAGNI AND MORBID ANATOMY + </p> + <p> + A great contemporary of Haller was Giovanni Battista Morgagni (1682-1771), + who pursued what Sydenham had neglected, the investigation in anatomy, + thus supplying a necessary counterpart to the great Englishman's work. + Morgagni's investigations were directed chiefly to the study of morbid + anatomy—the study of the structure of diseased tissue, both during + life and post mortem, in contrast to the normal anatomical structures. + This work cannot be said to have originated with him; for as early as 1679 + Bonnet had made similar, although less extensive, studies; and later many + investigators, such as Lancisi and Haller, had made post-mortem studies. + But Morgagni's De sedibus et causis morborum per anatomen indagatis was + the largest, most accurate, and best-illustrated collection of cases that + had ever been brought together, and marks an epoch in medical science. + From the time of the publication of Morgagni's researches, morbid anatomy + became a recognized branch of the medical science, and the effect of the + impetus thus given it has been steadily increasing since that time. + </p> + <p> + WILLIAM HUNTER + </p> + <p> + William Hunter (1718-1783) must always be remembered as one of the + greatest physicians and anatomists of the eighteenth century, and + particularly as the first great teacher of anatomy in England; but his + fame has been somewhat overshadowed by that of his younger brother John. + </p> + <p> + Hunter had been intended and educated for the Church, but on the advice of + the surgeon William Cullen he turned his attention to the study of + medicine. His first attempt at teaching was in 1746, when he delivered a + series of lectures on surgery for the Society of Naval Practitioners. + These lectures proved so interesting and instructive that he was at once + invited to give others, and his reputation as a lecturer was soon + established. He was a natural orator and story-teller, and he combined + with these attractive qualities that of thoroughness and clearness in + demonstrations, and although his lectures were two hours long he made them + so full of interest that his pupils seldom tired of listening. He believed + that he could do greater good to the world by "publicly teaching his art + than by practising it," and even during the last few days of his life, + when he was so weak that his friends remonstrated against it, he continued + his teaching, fainting from exhaustion at the end of his last lecture, + which preceded his death by only a few days. + </p> + <p> + For many years it was Hunter's ambition to establish a museum where the + study of anatomy, surgery, and medicine might be advanced, and in 1765 he + asked for a grant of a plot of ground for this purpose, offering to spend + seven thousand pounds on its erection besides endowing it with a + professorship of anatomy. Not being able to obtain this grant, however, he + built a house, in which were lecture and dissecting rooms, and his museum. + In this museum were anatomical preparations, coins, minerals, and + natural-history specimens. + </p> + <p> + Hunter's weakness was his love of controversy and his resentment of + contradiction. This brought him into strained relations with many of the + leading physicians of his time, notably his own brother John, who himself + was probably not entirely free from blame in the matter. Hunter is said to + have excused his own irritability on the grounds that being an anatomist, + and accustomed to "the passive submission of dead bodies," contradictions + became the more unbearable. Many of the physiological researches begun by + him were carried on and perfected by his more famous brother, particularly + his investigations of the capillaries, but he added much to the anatomical + knowledge of several structures of the body, notably as to the structure + of cartilages and joints. + </p> + <p> + JOHN HUNTER + </p> + <p> + In Abbot Islip's chapel in Westminster Abbey, close to the resting-place + of Ben Jonson, rest the remains of John Hunter (1728-1793), famous in the + annals of medicine as among the greatest physiologists and surgeons that + the world has ever produced: a man whose discoveries and inventions are + counted by scores, and whose field of research was only limited by the + outermost boundaries of eighteenth-century science, although his efforts + were directed chiefly along the lines of his profession. + </p> + <p> + Until about twenty years of age young Hunter had shown little aptitude for + study, being unusually fond of out-door sports and amusements; but about + that time, realizing that some occupation must be selected, he asked + permission of his brother William to attempt some dissections in his + anatomical school in London. To the surprise of his brother he made this + dissection unusually well; and being given a second, he acquitted himself + with such skill that his brother at once predicted that he would become a + great anatomist. Up to this time he had had no training of any kind to + prepare him for his professional career, and knew little of Greek or Latin—languages + entirely unnecessary for him, as he proved in all of his life work. Ottley + tells the story that, when twitted with this lack of knowledge of the + "dead languages" in after life, he said of his opponent, "I could teach + him that on the dead body which he never knew in any language, dead or + living." + </p> + <p> + By his second year in dissection he had become so skilful that he was + given charge of some of the classes in his brother's school; in 1754 he + became a surgeon's pupil in St. George's Hospital, and two years later + house-surgeon. Having by overwork brought on symptoms that seemed to + threaten consumption, he accepted the position of staff-surgeon to an + expedition to Belleisle in 1760, and two years later was serving with the + English army at Portugal. During all this time he was constantly engaged + in scientific researches, many of which, such as his observations of + gun-shot wounds, he put to excellent use in later life. On returning to + England much improved in health in 1763, he entered at once upon his + career as a London surgeon, and from that time forward his progress was a + practically uninterrupted series of successes in his profession. + </p> + <p> + Hunter's work on the study of the lymphatics was of great service to the + medical profession. This important net-work of minute vessels distributed + throughout the body had recently been made the object of much study, and + various students, including Haller, had made extensive investigations + since their discovery by Asellius. But Hunter, in 1758, was the first to + discover the lymphatics in the neck of birds, although it was his brother + William who advanced the theory that the function of these vessels was + that of absorbents. One of John Hunter's pupils, William Hewson + (1739-1774), first gave an account, in 1768, of the lymphatics in reptiles + and fishes, and added to his teacher's investigations of the lymphatics in + birds. These studies of the lymphatics have been regarded, perhaps with + justice, as Hunter's most valuable contributions to practical medicine. + </p> + <p> + In 1767 he met with an accident by which he suffered a rupture of the + tendo Achillis—the large tendon that forms the attachment of the + muscles of the calf to the heel. From observations of this accident, and + subsequent experiments upon dogs, he laid the foundation for the now + simple and effective operation for the cure of club feet and other + deformities involving the tendons. In 1772 he moved into his residence at + Earlscourt, Brompton, where he gathered about him a great menagerie of + animals, birds, reptiles, insects, and fishes, which he used in his + physiological and surgical experiments. Here he performed a countless + number of experiments—more, probably, than "any man engaged in + professional practice has ever conducted." These experiments varied in + nature from observations of the habits of bees and wasps to major surgical + operations performed upon hedgehogs, dogs, leopards, etc. It is said that + for fifteen years he kept a flock of geese for the sole purpose of + studying the process of development in eggs. + </p> + <p> + Hunter began his first course of lectures in 1772, being forced to do this + because he had been so repeatedly misquoted, and because he felt that he + could better gauge his own knowledge in this way. Lecturing was a sore + trial to him, as he was extremely diffident, and without writing out his + lectures in advance he was scarcely able to speak at all. In this he + presented a marked contrast to his brother William, who was a fluent and + brilliant speaker. Hunter's lectures were at best simple readings of the + facts as he had written them, the diffident teacher seldom raising his + eyes from his manuscript and rarely stopping until his complete lecture + had been read through. His lectures were, therefore, instructive rather + than interesting, as he used infinite care in preparing them; but + appearing before his classes was so dreaded by him that he is said to have + been in the habit of taking a half-drachm of laudanum before each lecture + to nerve him for the ordeal. One is led to wonder by what name he shall + designate that quality of mind that renders a bold and fearless surgeon + like Hunter, who is undaunted in the face of hazardous and dangerous + operations, a stumbling, halting, and "frightened" speaker before a little + band of, at most, thirty young medical students. And yet this same thing + is not unfrequently seen among the boldest surgeons. + </p> + <p> + Hunter's Operation for the Cure of Aneurisms + </p> + <p> + It should be an object-lesson to those who, ignorantly or otherwise, + preach against the painless vivisection as practised to-day, that by the + sacrifice of a single deer in the cause of science Hunter discovered a + fact in physiology that has been the means of saving thousands of human + lives and thousands of human bodies from needless mutilation. We refer to + the discovery of the "collateral circulation" of the blood, which led, + among other things, to Hunter's successful operation upon aneurisms. + </p> + <p> + Simply stated, every organ or muscle of the body is supplied by one large + artery, whose main trunk distributes the blood into its lesser branches, + and thence through the capillaries. Cutting off this main artery, it would + seem, should cut off entirely the blood-supply to the particular organ + which is supplied by this vessel; and until the time of Hunter's + demonstration this belief was held by most physiologists. But nature has + made a provision for this possible stoppage of blood-supply from a single + source, and has so arranged that some of the small arterial branches + coming from the main supply-trunk are connected with other arterial + branches coming from some other supply-trunk. Under normal conditions the + main arterial trunks supply their respective organs, the little connecting + arterioles playing an insignificant part. But let the main supply-trunk be + cut off or stopped for whatever reason, and a remarkable thing takes + place. The little connecting branches begin at once to enlarge and draw + blood from the neighboring uninjured supply-trunk, This enlargement + continues until at last a new route for the circulation has been + established, the organ no longer depending on the now defunct original + arterial trunk, but getting on as well as before by this "collateral" + circulation that has been established. + </p> + <p> + The thorough understanding of this collateral circulation is one of the + most important steps in surgery, for until it was discovered amputations + were thought necessary in such cases as those involving the artery + supplying a leg or arm, since it was supposed that, the artery being + stopped, death of the limb and the subsequent necessity for amputation + were sure to follow. Hunter solved this problem by a single operation upon + a deer, and his practicality as a surgeon led him soon after to apply this + knowledge to a certain class of surgical cases in a most revolutionary and + satisfactory manner. + </p> + <p> + What led to Hunter's far-reaching discovery was his investigation as to + the cause of the growth of the antlers of the deer. Wishing to ascertain + just what part the blood-supply on the opposite sides of the neck played + in the process of development, or, perhaps more correctly, to see what + effect cutting off the main blood-supply would have, Hunter had one of the + deer of Richmond Park caught and tied, while he placed a ligature around + one of the carotid arteries—one of the two principal arteries that + supply the head with blood. He observed that shortly after this the antler + (which was only half grown and consequently very vascular) on the side of + the obliterated artery became cold to the touch—from the lack of + warmth-giving blood. There was nothing unexpected in this, and Hunter + thought nothing of it until a few days later, when he found, to his + surprise, that the antler had become as warm as its fellow, and was + apparently increasing in size. Puzzled as to how this could be, and + suspecting that in some way his ligature around the artery had not been + effective, he ordered the deer killed, and on examination was astonished + to find that while his ligature had completely shut off the blood-supply + from the source of that carotid artery, the smaller arteries had become + enlarged so as to supply the antler with blood as well as ever, only by a + different route. + </p> + <p> + Hunter soon had a chance to make a practical application of the knowledge + thus acquired. This was a case of popliteal aneurism, operations for which + had heretofore proved pretty uniformly fatal. An aneurism, as is generally + understood, is an enlargement of a certain part of an artery, this + enlargement sometimes becoming of enormous size, full of palpitating + blood, and likely to rupture with fatal results at any time. If by any + means the blood can be allowed to remain quiet for even a few hours in + this aneurism it will form a clot, contract, and finally be absorbed and + disappear without any evil results. The problem of keeping the blood + quiet, with the heart continually driving it through the vessel, is not a + simple one, and in Hunter's time was considered so insurmountable that + some surgeons advocated amputation of any member having an aneurism, while + others cut down upon the tumor itself and attempted to tie off the artery + above and below. The first of these operations maimed the patient for + life, while the second was likely to prove fatal. + </p> + <p> + In pondering over what he had learned about collateral circulation and the + time required for it to become fully established, Hunter conceived the + idea that if the blood-supply was cut off from above the aneurism, thus + temporarily preventing the ceaseless pulsations from the heart, this blood + would coagulate and form a clot before the collateral circulation could + become established or could affect it. The patient upon whom he performed + his now celebrated operation was afflicted with a popliteal aneurism—that + is, the aneurism was located on the large popliteal artery just behind the + knee-joint. Hunter, therefore, tied off the femoral, or main supplying + artery in the thigh, a little distance above the aneurism. The operation + was entirely successful, and in six weeks' time the patient was able to + leave the hospital, and with two sound limbs. Naturally the simplicity and + success of this operation aroused the attention of Europe, and, alone, + would have made the name of Hunter immortal in the annals of surgery. The + operation has ever since been called the "Hunterian" operation for + aneurism, but there is reason to believe that Dominique Anel (born about + 1679) performed a somewhat similar operation several years earlier. It is + probable, however, that Hunter had never heard of this work of Anel, and + that his operation was the outcome of his own independent reasoning from + the facts he had learned about collateral circulation. Furthermore, + Hunter's mode of operation was a much better one than Anel's, and, while + Anel's must claim priority, the credit of making it widely known will + always be Hunter's. + </p> + <p> + The great services of Hunter were recognized both at home and abroad, and + honors and positions of honor and responsibility were given him. In 1776 + he was appointed surgeon-extraordinary to the king; in 1783 he was elected + a member of the Royal Society of Medicine and of the Royal Academy of + Surgery at Paris; in 1786 he became deputy surgeon-general of the army; + and in 1790 he was appointed surgeon-general and inspector-general of + hospitals. All these positions he filled with credit, and he was actively + engaged in his tireless pursuit of knowledge and in discharging his many + duties when in October, 1793, he was stricken while addressing some + colleagues, and fell dead in the arms of a fellow-physician. + </p> + <p> + LAZZARO SPALLANZANI + </p> + <p> + Hunter's great rival among contemporary physiologists was the Italian + Lazzaro Spallanzani (1729-1799), one of the most picturesque figures in + the history of science. He was not educated either as a scientist or + physician, devoting, himself at first to philosophy and the languages, + afterwards studying law, and later taking orders. But he was a keen + observer of nature and of a questioning and investigating mind, so that he + is remembered now chiefly for his discoveries and investigations in the + biological sciences. One important demonstration was his controversion of + the theory of abiogenesis, or "spontaneous generation," as propounded by + Needham and Buffon. At the time of Needham's experiments it had long been + observed that when animal or vegetable matter had lain in water for a + little time—long enough for it to begin to undergo decomposition—the + water became filled with microscopic creatures, the "infusoria + animalculis." This would tend to show, either that the water or the animal + or vegetable substance contained the "germs" of these minute organisms, or + else that they were generated spontaneously. It was known that boiling + killed these animalcules, and Needham agreed, therefore, that if he first + heated the meat or vegetables, and also the water containing them, and + then placed them in hermetically scaled jars—if he did this, and + still the animalcules made their appearance, it would be proof-positive + that they had been generated spontaneously. Accordingly he made numerous + experiments, always with the same results—that after a few days the + water was found to swarm with the microscopic creatures. The thing seemed + proven beyond question—providing, of course, that there had been no + slips in the experiments. + </p> + <p> + But Abbe Spallanzani thought that he detected such slips in Needham's + experiment. The possibility of such slips might come in several ways: the + contents of the jar might not have been boiled for a sufficient length of + time to kill all the germs, or the air might not have been excluded + completely by the sealing process. To cover both these contingencies, + Spallanzani first hermetically sealed the glass vessels and then boiled + them for three-quarters of an hour. Under these circumstances no + animalcules ever made their appearance—a conclusive demonstration + that rendered Needham's grounds for his theory at once untenable.(2) + </p> + <p> + Allied to these studies of spontaneous generation were Spallanzani's + experiments and observations on the physiological processes of generation + among higher animals. He experimented with frogs, tortoises, and dogs; and + settled beyond question the function of the ovum and spermatozoon. + Unfortunately he misinterpreted the part played by the spermatozoa in + believing that their surrounding fluid was equally active in the + fertilizing process, and it was not until some forty years later (1824) + that Dumas corrected this error. + </p> + <p> + THE CHEMICAL THEORY OF DIGESTION + </p> + <p> + Among the most interesting researches of Spallanzani were his experiments + to prove that digestion, as carried on in the stomach, is a chemical + process. In this he demonstrated, as Rene Reaumur had attempted to + demonstrate, that digestion could be carried on outside the walls of the + stomach as an ordinary chemical reaction, using the gastric juice as the + reagent for performing the experiment. The question as to whether the + stomach acted as a grinding or triturating organ, rather than as a + receptacle for chemical action, had been settled by Reaumur and was no + longer a question of general dispute. Reaumur had demonstrated + conclusively that digestion would take place in the stomach in the same + manner and the same time if the substance to be digested was protected + from the peristalic movements of the stomach and subjected to the action + of the gastric juice only. He did this by introducing the substances to be + digested into the stomach in tubes, and thus protected so that while the + juices of the stomach could act upon them freely they would not be + affected by any movements of the organ. + </p> + <p> + Following up these experiments, he attempted to show that digestion could + take place outside the body as well as in it, as it certainly should if it + were a purely chemical process. He collected quantities of gastric juice, + and placing it in suitable vessels containing crushed grain or flesh, kept + the mixture at about the temperature of the body for several hours. After + repeated experiments of this kind, apparently conducted with great care, + Reaumur reached the conclusion that "the gastric juice has no more effect + out of the living body in dissolving or digesting the food than water, + mucilage, milk, or any other bland fluid."(3) Just why all of these + experiments failed to demonstrate a fact so simple does not appear; but to + Spallanzani, at least, they were by no means conclusive, and he proceeded + to elaborate upon the experiments of Reaumur. He made his experiments in + scaled tubes exposed to a certain degree of heat, and showed conclusively + that the chemical process does go on, even when the food and gastric juice + are removed from their natural environment in the stomach. In this he was + opposed by many physiologists, among them John Hunter, but the truth of + his demonstrations could not be shaken, and in later years we find Hunter + himself completing Spallanzani's experiments by his studies of the + post-mortem action of the gastric juice upon the stomach walls. + </p> + <p> + That Spallanzani's and Hunter's theories of the action of the gastric + juice were not at once universally accepted is shown by an essay written + by a learned physician in 1834. In speaking of some of Spallanzani's + demonstrations, he writes: "In some of the experiments, in order to give + the flesh or grains steeped in the gastric juice the same temperature with + the body, the phials were introduced under the armpits. But this is not a + fair mode of ascertaining the effects of the gastric juice out of the + body; for the influence which life may be supposed to have on the solution + of the food would be secured in this case. The affinities connected with + life would extend to substances in contact with any part of the system: + substances placed under the armpits are not placed at least in the same + circumstances with those unconnected with a living animal." But just how + this writer reaches the conclusion that "the experiments of Reaumur and + Spallanzani give no evidence that the gastric juice has any peculiar + influence more than water or any other bland fluid in digesting the + food"(4) is difficult to understand. + </p> + <p> + The concluding touches were given to the new theory of digestion by John + Hunter, who, as we have seen, at first opposed Spallanzani, but who + finally became an ardent champion of the chemical theory. Hunter now + carried Spallanzani's experiments further and proved the action of the + digestive fluids after death. For many years anatomists had been puzzled + by pathological lesion of the stomach, found post mortem, when no symptoms + of any disorder of the stomach had been evinced during life. Hunter + rightly conceived that these lesions were caused by the action of the + gastric juice, which, while unable to act upon the living tissue, + continued its action chemically after death, thus digesting the walls of + the stomach in which it had been formed. And, as usual with his + observations, he turned this discovery to practical use in accounting for + certain phenomena of digestion. The following account of the stomach being + digested after death was written by Hunter at the desire of Sir John + Pringle, when he was president of the Royal Society, and the circumstance + which led to this is as follows: "I was opening, in his presence, the body + of a patient of his own, where the stomach was in part dissolved, which + appeared to him very unaccountable, as there had been no previous symptom + that could have led him to suspect any disease in the stomach. I took that + opportunity of giving him my ideas respecting it, and told him that I had + long been making experiments on digestion, and considered this as one of + the facts which proved a converting power in the gastric juice.... There + are a great many powers in nature which the living principle does not + enable the animal matter, with which it is combined, to resist—viz., + the mechanical and most of the strongest chemical solvents. It renders it, + however, capable of resisting the powers of fermentation, digestion, and + perhaps several others, which are well known to act on the same matter + when deprived of the living principle and entirely to decompose it." + </p> + <p> + Hunter concludes his paper with the following paragraph: "These + appearances throw considerable light on the principle of digestion, and + show that it is neither a mechanical power, nor contractions of the + stomach, nor heat, but something secreted in the coats of the stomach, and + thrown into its cavity, which there animalizes the food or assimilates it + to the nature of the blood. The power of this juice is confined or limited + to certain substances, especially of the vegetable and animal kingdoms; + and although this menstruum is capable of acting independently of the + stomach, yet it is indebted to that viscus for its continuance."(5) + </p> + <p> + THE FUNCTION OF RESPIRATION + </p> + <p> + It is a curious commentary on the crude notions of mechanics of previous + generations that it should have been necessary to prove by experiment that + the thin, almost membranous stomach of a mammal has not the power to + pulverize, by mere attrition, the foods that are taken into it. However, + the proof was now for the first time forthcoming, and the question of the + general character of the function of digestion was forever set at rest. + Almost simultaneously with this great advance, corresponding progress was + made in an allied field: the mysteries of respiration were at last cleared + up, thanks to the new knowledge of chemistry. The solution of the problem + followed almost as a matter of course upon the advances of that science in + the latter part of the century. Hitherto no one since Mayow, of the + previous century, whose flash of insight had been strangely overlooked and + forgotten, had even vaguely surmised the true function of the lungs. The + great Boerhaave had supposed that respiration is chiefly important as an + aid to the circulation of the blood; his great pupil, Haller, had believed + to the day of his death in 1777 that the main purpose of the function is + to form the voice. No genius could hope to fathom the mystery of the lungs + so long as air was supposed to be a simple element, serving a mere + mechanical purpose in the economy of the earth. + </p> + <p> + But the discovery of oxygen gave the clew, and very soon all the chemists + were testing the air that came from the lungs—Dr. Priestley, as + usual, being in the van. His initial experiments were made in 1777, and + from the outset the problem was as good as solved. Other experimenters + confirmed his results in all their essentials—notably Scheele and + Lavoisier and Spallanzani and Davy. It was clearly established that there + is chemical action in the contact of the air with the tissue of the lungs; + that some of the oxygen of the air disappears, and that carbonic-acid gas + is added to the inspired air. It was shown, too, that the blood, having + come in contact with the air, is changed from black to red in color. These + essentials were not in dispute from the first. But as to just what + chemical changes caused these results was the subject of controversy. + Whether, for example, oxygen is actually absorbed into the blood, or + whether it merely unites with carbon given off from the blood, was long in + dispute. + </p> + <p> + Each of the main disputants was biased by his own particular views as to + the moot points of chemistry. Lavoisier, for example, believed oxygen gas + to be composed of a metal oxygen combined with the alleged element heat; + Dr. Priestley thought it a compound of positive electricity and + phlogiston; and Humphry Davy, when he entered the lists a little later, + supposed it to be a compound of oxygen and light. Such mistaken notions + naturally complicated matters and delayed a complete understanding of the + chemical processes of respiration. It was some time, too, before the idea + gained acceptance that the most important chemical changes do not occur in + the lungs themselves, but in the ultimate tissues. Indeed, the matter was + not clearly settled at the close of the century. Nevertheless, the problem + of respiration had been solved in its essentials. Moreover, the vastly + important fact had been established that a process essentially identical + with respiration is necessary to the existence not only of all creatures + supplied with lungs, but to fishes, insects, and even vegetables—in + short, to every kind of living organism. + </p> + <p> + ERASMUS DARWIN AND VEGETABLE PHYSIOLOGY + </p> + <p> + Some interesting experiments regarding vegetable respiration were made + just at the close of the century by Erasmus Darwin, and recorded in his + Botanic Garden as a foot-note to the verse: + </p> + <p> + "While spread in air the leaves respiring play." + </p> + <p> + These notes are worth quoting at some length, as they give a clear idea of + the physiological doctrines of the time (1799), while taking advance + ground as to the specific matter in question: + </p> + <p> + "There have been various opinions," Darwin says, "concerning the use of + the leaves of plants in the vegetable economy. Some have contended that + they are perspiratory organs. This does not seem probable from an + experiment of Dr. Hales, Vegetable Statics, p. 30. He, found, by cutting + off branches of trees with apples on them and taking off the leaves, that + an apple exhaled about as much as two leaves the surfaces of which were + nearly equal to the apple; whence it would appear that apples have as good + a claim to be termed perspiratory organs as leaves. Others have believed + them excretory organs of excrementitious juices, but as the vapor exhaled + from vegetables has no taste, this idea is no more probable than the + other; add to this that in most weathers they do not appear to perspire or + exhale at all. + </p> + <p> + "The internal surface of the lungs or air-vessels in men is said to be + equal to the external surface of the whole body, or almost fifteen square + feet; on this surface the blood is exposed to the influence of the + respired air through the medium, however, of a thin pellicle; by this + exposure to the air it has its color changed from deep red to bright + scarlet, and acquires something so necessary to the existence of life that + we can live scarcely a minute without this wonderful process. + </p> + <p> + "The analogy between the leaves of plants and the lungs or gills of + animals seems to embrace so many circumstances that we can scarcely + withhold our consent to their performing similar offices. + </p> + <p> + "1. The great surface of leaves compared to that of the trunk and branches + of trees is such that it would seem to be an organ well adapted for the + purpose of exposing the vegetable juices to the influence of the air; + this, however, we shall see afterwards is probably performed only by their + upper surfaces, yet even in this case the surface of the leaves in general + bear a greater proportion to the surface of the tree than the lungs of + animals to their external surfaces. + </p> + <p> + "2. In the lung of animals the blood, after having been exposed to the air + in the extremities of the pulmonary artery, is changed in color from deep + red to bright scarlet, and certainly in some of its essential properties + it is then collected by the pulmonary vein and returned to the heart. To + show a similarity of circumstances in the leaves of plants, the following + experiment was made, June 24, 1781. A stalk with leaves and seed-vessels + of large spurge (Euphorbia helioscopia) had been several days placed in a + decoction of madder (Rubia tinctorum) so that the lower part of the stem + and two of the undermost leaves were immersed in it. After having washed + the immersed leaves in clear water I could readily discover the color of + the madder passing along the middle rib of each leaf. The red artery was + beautifully visible on the under and on the upper surface of the leaf; but + on the upper side many red branches were seen going from it to the + extremities of the leaf, which on the other side were not visible except + by looking through it against the light. On this under side a system of + branching vessels carrying a pale milky fluid were seen coming from the + extremities of the leaf, and covering the whole under side of it, and + joining two large veins, one on each side of the red artery in the middle + rib of the leaf, and along with it descending to the foot-stalk or + petiole. On slitting one of these leaves with scissors, and having a + magnifying-glass ready, the milky blood was seen oozing out of the + returning veins on each side of the red artery in the middle rib, but none + of the red fluid from the artery. + </p> + <p> + "All these appearances were more easily seen in a leaf of Picris treated + in the same manner; for in this milky plant the stems and middle rib of + the leaves are sometimes naturally colored reddish, and hence the color of + the madder seemed to pass farther into the ramifications of their + leaf-arteries, and was there beautifully visible with the returning + branches of milky veins on each side." + </p> + <p> + Darwin now goes on to draw an incorrect inference from his observations: + </p> + <p> + "3. From these experiments," he says, "the upper surface of the leaf + appeared to be the immediate organ of respiration, because the colored + fluid was carried to the extremities of the leaf by vessels most + conspicuous on the upper surface, and there changed into a milky fluid, + which is the blood of the plant, and then returned by concomitant veins on + the under surface, which were seen to ooze when divided with scissors, and + which, in Picris, particularly, render the under surface of the leaves + greatly whiter than the upper one." + </p> + <p> + But in point of fact, as studies of a later generation were to show, it is + the under surface of the leaf that is most abundantly provided with + stomata, or "breathing-pores." From the stand-point of this later + knowledge, it is of interest to follow our author a little farther, to + illustrate yet more fully the possibility of combining correct + observations with a faulty inference. + </p> + <p> + "4. As the upper surface of leaves constitutes the organ of respiration, + on which the sap is exposed in the termination of arteries beneath a thin + pellicle to the action of the atmosphere, these surfaces in many plants + strongly repel moisture, as cabbage leaves, whence the particles of rain + lying over their surfaces without touching them, as observed by Mr. + Melville (Essays Literary and Philosophical: Edinburgh), have the + appearance of globules of quicksilver. And hence leaves with the upper + surfaces on water wither as soon as in the dry air, but continue green for + many days if placed with the under surface on water, as appears in the + experiments of Monsieur Bonnet (Usage des Feuilles). Hence some aquatic + plants, as the water-lily (Nymphoea), have the lower sides floating on the + water, while the upper surfaces remain dry in the air. + </p> + <p> + "5. As those insects which have many spiracula, or breathing apertures, as + wasps and flies, are immediately suffocated by pouring oil upon them, I + carefully covered with oil the surfaces of several leaves of phlomis, of + Portugal laurel, and balsams, and though it would not regularly adhere, I + found them all die in a day or two. + </p> + <p> + "It must be added that many leaves are furnished with muscles about their + foot-stalks, to turn their surfaces to the air or light, as mimosa or + Hedysarum gyrans. From all these analogies I think there can be no doubt + but that leaves of trees are their lungs, giving out a phlogistic material + to the atmosphere, and absorbing oxygen, or vital air. + </p> + <p> + "6. The great use of light to vegetation would appear from this theory to + be by disengaging vital air from the water which they perspire, and thence + to facilitate its union with their blood exposed beneath the thin surface + of their leaves; since when pure air is thus applied it is probable that + it can be more readily absorbed. Hence, in the curious experiments of Dr. + Priestley and Mr. Ingenhouz, some plants purified less air than others—that + is, they perspired less in the sunshine; and Mr. Scheele found that by + putting peas into water which about half covered them they converted the + vital air into fixed air, or carbonic-acid gas, in the same manner as in + animal respiration. + </p> + <p> + "7. The circulation in the lungs or leaves of plants is very similar to + that of fish. In fish the blood, after having passed through their gills, + does not return to the heart as from the lungs of air-breathing animals, + but the pulmonary vein taking the structure of an artery after having + received the blood from the gills, which there gains a more florid color, + distributes it to the other parts of their bodies. The same structure + occurs in the livers of fish, whence we see in those animals two + circulations independent of the power of the heart—viz., that + beginning at the termination of the veins of the gills and branching + through the muscles, and that which passes through the liver; both which + are carried on by the action of those respective arteries and veins."(6) + </p> + <p> + Darwin is here a trifle fanciful in forcing the analogy between plants and + animals. The circulatory system of plants is really not quite so + elaborately comparable to that of fishes as he supposed. But the + all-important idea of the uniformity underlying the seeming diversity of + Nature is here exemplified, as elsewhere in the writings of Erasmus + Darwin; and, more specifically, a clear grasp of the essentials of the + function of respiration is fully demonstrated. + </p> + <p> + ZOOLOGY AT THE CLOSE OF THE EIGHTEENTH CENTURY + </p> + <p> + Several causes conspired to make exploration all the fashion during the + closing epoch of the eighteenth century. New aid to the navigator had been + furnished by the perfected compass and quadrant, and by the invention of + the chronometer; medical science had banished scurvy, which hitherto had + been a perpetual menace to the voyager; and, above all, the restless + spirit of the age impelled the venturesome to seek novelty in fields + altogether new. Some started for the pole, others tried for a northeast or + northwest passage to India, yet others sought the great fictitious + antarctic continent told of by tradition. All these of course failed of + their immediate purpose, but they added much to the world's store of + knowledge and its fund of travellers' tales. + </p> + <p> + Among all these tales none was more remarkable than those which told of + strange living creatures found in antipodal lands. And here, as did not + happen in every field, the narratives were often substantiated by the + exhibition of specimens that admitted no question. Many a company of + explorers returned more or less laden with such trophies from the animal + and vegetable kingdoms, to the mingled astonishment, delight, and + bewilderment of the closet naturalists. The followers of Linnaeus in the + "golden age of natural history," a few decades before, had increased the + number of known species of fishes to about four hundred, of birds to one + thousand, of insects to three thousand, and of plants to ten thousand. But + now these sudden accessions from new territories doubled the figure for + plants, tripled it for fish and birds, and brought the number of described + insects above twenty thousand. Naturally enough, this wealth of new + material was sorely puzzling to the classifiers. The more discerning began + to see that the artificial system of Linnaeus, wonderful and useful as it + had been, must be advanced upon before the new material could be + satisfactorily disposed of. The way to a more natural system, based on + less arbitrary signs, had been pointed out by Jussieu in botany, but the + zoologists were not prepared to make headway towards such a system until + they should gain a wider understanding of the organisms with which they + had to deal through comprehensive studies of anatomy. Such studies of + individual forms in their relations to the entire scale of organic beings + were pursued in these last decades of the century, but though two or three + most important generalizations were achieved (notably Kaspar Wolff's + conception of the cell as the basis of organic life, and Goethe's + all-important doctrine of metamorphosis of parts), yet, as a whole, the + work of the anatomists of the period was germinative rather than + fruit-bearing. Bichat's volumes, telling of the recognition of the + fundamental tissues of the body, did not begin to appear till the last + year of the century. The announcement by Cuvier of the doctrine of + correlation of parts bears the same date, but in general the studies of + this great naturalist, which in due time were to stamp him as the + successor of Linnaeus, were as yet only fairly begun. + </p> + <p> + <a name="link2H_4_0006" id="link2H_4_0006"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + V. ANATOMY AND PHYSIOLOGY IN THE NINETEENTH CENTURY + </h2> + <h3> + CUVIER AND THE CORRELATION OF PARTS + </h3> + <p> + We have seen that the focal points of the physiological world towards the + close of the eighteenth century were Italy and England, but when + Spallanzani and Hunter passed away the scene shifted to France. The time + was peculiarly propitious, as the recent advances in many lines of science + had brought fresh data for the student of animal life which were in need + of classification, and, as several minds capable of such a task were in + the field, it was natural that great generalizations should have come to + be quite the fashion. Thus it was that Cuvier came forward with a + brand-new classification of the animal kingdom, establishing four great + types of being, which he called vertebrates, mollusks, articulates, and + radiates. Lamarck had shortly before established the broad distinction + between animals with and those without a backbone; Cuvier's Classification + divided the latter—the invertebrates—into three minor groups. + And this division, familiar ever since to all students of zoology, has + only in very recent years been supplanted, and then not by revolution, but + by a further division, which the elaborate recent studies of lower forms + of life seemed to make desirable. + </p> + <p> + In the course of those studies of comparative anatomy which led to his new + classification, Cuvier's attention was called constantly to the peculiar + co-ordination of parts in each individual organism. Thus an animal with + sharp talons for catching living prey—as a member of the cat tribe—has + also sharp teeth, adapted for tearing up the flesh of its victim, and a + particular type of stomach, quite different from that of herbivorous + creatures. This adaptation of all the parts of the animal to one another + extends to the most diverse parts of the organism, and enables the skilled + anatomist, from the observation of a single typical part, to draw + inferences as to the structure of the entire animal—a fact which was + of vast aid to Cuvier in his studies of paleontology. It did not enable + Cuvier, nor does it enable any one else, to reconstruct fully the extinct + animal from observation of a single bone, as has sometimes been asserted, + but what it really does establish, in the hands of an expert, is + sufficiently astonishing. + </p> + <p> + "While the study of the fossil remains of the greater quadrupeds is more + satisfactory," he writes, "by the clear results which it affords, than + that of the remains of other animals found in a fossil state, it is also + complicated with greater and more numerous difficulties. Fossil shells are + usually found quite entire, and retaining all the characters requisite for + comparing them with the specimens contained in collections of natural + history, or represented in the works of naturalists. Even the skeletons of + fishes are found more or less entire, so that the general forms of their + bodies can, for the most part, be ascertained, and usually, at least, + their generic and specific characters are determinable, as these are + mostly drawn from their solid parts. In quadrupeds, on the contrary, even + when their entire skeletons are found, there is great difficulty in + discovering their distinguishing characters, as these are chiefly founded + upon their hairs and colors and other marks which have disappeared + previous to their incrustation. It is also very rare to find any fossil + skeletons of quadrupeds in any degree approaching to a complete state, as + the strata for the most part only contain separate bones, scattered + confusedly and almost always broken and reduced to fragments, which are + the only means left to naturalists for ascertaining the species or genera + to which they have belonged. + </p> + <p> + "Fortunately comparative anatomy, when thoroughly understood, enables us + to surmount all these difficulties, as a careful application of its + principles instructs us in the correspondences and dissimilarities of the + forms of organized bodies of different kinds, by which each may be + rigorously ascertained from almost every fragment of its various parts and + organs. + </p> + <p> + "Every organized individual forms an entire system of its own, all the + parts of which naturally correspond, and concur to produce a certain + definite purpose, by reciprocal reaction, or by combining towards the same + end. Hence none of these separate parts can change their forms without a + corresponding change in the other parts of the same animal, and + consequently each of these parts, taken separately, indicates all the + other parts to which it has belonged. Thus, as I have elsewhere shown, if + the viscera of an animal are so organized as only to be fitted for the + digestion of recent flesh, it is also requisite that the jaws should be so + constructed as to fit them for devouring prey; the claws must be + constructed for seizing and tearing it to pieces; the teeth for cutting + and dividing its flesh; the entire system of the limbs, or organs of + motion, for pursuing and overtaking it; and the organs of sense for + discovering it at a distance. Nature must also have endowed the brain of + the animal with instincts sufficient for concealing itself and for laying + plans to catch its necessary victims.... + </p> + <p> + "To enable the animal to carry off its prey when seized, a corresponding + force is requisite in the muscles which elevate the head, and this + necessarily gives rise to a determinate form of the vertebrae to which + these muscles are attached and of the occiput into which they are + inserted. In order that the teeth of a carnivorous animal may be able to + cut the flesh, they require to be sharp, more or less so in proportion to + the greater or less quantity of flesh that they have to cut. It is + requisite that their roots should be solid and strong, in proportion to + the quantity and size of the bones which they have to break to pieces. The + whole of these circumstances must necessarily influence the development + and form of all the parts which contribute to move the jaws...." + </p> + <p> + After these observations, it will be easily seen that similar conclusions + may be drawn with respect to the limbs of carnivorous animals, which + require particular conformations to fit them for rapidity of motion in + general; and that similar considerations must influence the forms and + connections of the vertebrae and other bones constituting the trunk of the + body, to fit them for flexibility and readiness of motion in all + directions. The bones also of the nose, of the orbit, and of the ears + require certain forms and structures to fit them for giving perfection to + the senses of smell, sight, and hearing, so necessary to animals of prey. + In short, the shape and structure of the teeth regulate the forms of the + condyle, of the shoulder-blade, and of the claws, in the same manner as + the equation of a curve regulates all its other properties; and as in + regard to any particular curve all its properties may be ascertained by + assuming each separate property as the foundation of a particular + equation, in the same manner a claw, a shoulder-blade, a condyle, a leg or + arm bone, or any other bone separately considered, enables us to discover + the description of teeth to which they have belonged; and so also + reciprocally we may determine the forms of the other bones from the teeth. + Thus commencing our investigations by a careful survey of any one bone by + itself, a person who is sufficiently master of the laws of organic + structure may, as it were, reconstruct the whole animal to which that bone + belonged."(1) + </p> + <p> + We have already pointed out that no one is quite able to perform the + necromantic feat suggested in the last sentence; but the exaggeration is + pardonable in the enthusiast to whom the principle meant so much and in + whose hands it extended so far. + </p> + <p> + Of course this entire principle, in its broad outlines, is something with + which every student of anatomy had been familiar from the time when + anatomy was first studied, but the full expression of the "law of + co-ordination," as Cuvier called it, had never been explicitly made + before; and, notwithstanding its seeming obviousness, the exposition which + Cuvier made of it in the introduction to his classical work on comparative + anatomy, which was published during the first decade of the nineteenth + century, ranks as a great discovery. It is one of those generalizations + which serve as guideposts to other discoveries. + </p> + <p> + BICHAT AND THE BODILY TISSUES + </p> + <p> + Much the same thing may be said of another generalization regarding the + animal body, which the brilliant young French physician Marie Francois + Bichat made in calling attention to the fact that each vertebrate + organism, including man, has really two quite different sets of organs—one + set under volitional control, and serving the end of locomotion, the other + removed from volitional control, and serving the ends of the "vital + processes" of digestion, assimilation, and the like. He called these sets + of organs the animal system and the organic system, respectively. The + division thus pointed out was not quite new, for Grimaud, professor of + physiology in the University of Montpellier, had earlier made what was + substantially the same classification of the functions into "internal or + digestive and external or locomotive"; but it was Bichat's exposition that + gave currency to the idea. + </p> + <p> + Far more important, however, was another classification which Bichat put + forward in his work on anatomy, published just at the beginning of the + last century. This was the division of all animal structures into what + Bichat called tissues, and the pointing out that there are really only a + few kinds of these in the body, making up all the diverse organs. Thus + muscular organs form one system; membranous organs another; glandular + organs a third; the vascular mechanism a fourth, and so on. The + distinction is so obvious that it seems rather difficult to conceive that + it could have been overlooked by the earliest anatomists; but, in point of + fact, it is only obvious because now it has been familiarly taught for + almost a century. It had never been given explicit expression before the + time of Bichat, though it is said that Bichat himself was somewhat + indebted for it to his master, Desault, and to the famous alienist Pinel. + </p> + <p> + However that may be, it is certain that all subsequent anatomists have + found Bichat's classification of the tissues of the utmost value in their + studies of the animal functions. Subsequent advances were to show that the + distinction between the various tissues is not really so fundamental as + Bichat supposed, but that takes nothing from the practical value of the + famous classification. + </p> + <p> + It was but a step from this scientific classification of tissues to a + similar classification of the diseases affecting them, and this was one of + the greatest steps towards placing medicine on the plane of an exact + science. This subject of these branches completely fascinated Bichat, and + he exclaimed, enthusiastically: "Take away some fevers and nervous + trouble, and all else belongs to the kingdom of pathological anatomy." But + out of this enthusiasm came great results. Bichat practised as he + preached, and, believing that it was only possible to understand disease + by observing the symptoms carefully at the bedside, and, if the disease + terminated fatally, by post-mortem examination, he was so arduous in his + pursuit of knowledge that within a period of less than six months he had + made over six hundred autopsies—a record that has seldom, if ever, + been equalled. Nor were his efforts fruitless, as a single example will + suffice to show. By his examinations he was able to prove that diseases of + the chest, which had formerly been classed under the indefinite name + "peripneumonia," might involve three different structures, the pleural sac + covering the lungs, the lung itself, and the bronchial tubes, the diseases + affecting these organs being known respectively as pleuritis, pneumonia, + and bronchitis, each one differing from the others as to prognosis and + treatment. The advantage of such an exact classification needs no + demonstration. + </p> + <p> + LISTER AND THE PERFECTED MICROSCOPE + </p> + <p> + At the same time when these broad macroscopical distinctions were being + drawn there were other workers who were striving to go even deeper into + the intricacies of the animal mechanism with the aid of the microscope. + This undertaking, however, was beset with very great optical difficulties, + and for a long time little advance was made upon the work of preceding + generations. Two great optical barriers, known technically as spherical + and chromatic aberration—the one due to a failure of the rays of + light to fall all in one plane when focalized through a lens, the other + due to the dispersive action of the lens in breaking the white light into + prismatic colors—confronted the makers of microscopic lenses, and + seemed all but insuperable. The making of achromatic lenses for telescopes + had been accomplished, it is true, by Dolland in the previous century, by + the union of lenses of crown glass with those of flint glass, these two + materials having different indices of refraction and dispersion. But, + aside from the mechanical difficulties which arise when the lens is of the + minute dimensions required for use with the microscope, other perplexities + are introduced by the fact that the use of a wide pencil of light is a + desideratum, in order to gain sufficient illumination when large + magnification is to be secured. + </p> + <p> + In the attempt to overcome those difficulties, the foremost physical + philosophers of the time came to the aid of the best opticians. Very early + in the century, Dr. (afterwards Sir David) Brewster, the renowned Scotch + physicist, suggested that certain advantages might accrue from the use of + such gems as have high refractive and low dispersive indices, in place of + lenses made of glass. Accordingly lenses were made of diamond, of + sapphire, and so on, and with some measure of success. But in 1812 a much + more important innovation was introduced by Dr. William Hyde Wollaston, + one of the greatest and most versatile, and, since the death of Cavendish, + by far the most eccentric of English natural philosophers. This was the + suggestion to use two plano-convex lenses, placed at a prescribed distance + apart, in lieu of the single double-convex lens generally used. This + combination largely overcame the spherical aberration, and it gained + immediate fame as the "Wollaston doublet." + </p> + <p> + To obviate loss of light in such a doublet from increase of reflecting + surfaces, Dr. Brewster suggested filling the interspace between the two + lenses with a cement having the same index of refraction as the lenses + themselves—an improvement of manifest advantage. An improvement yet + more important was made by Dr. Wollaston himself in the introduction of + the diaphragm to limit the field of vision between the lenses, instead of + in front of the anterior lens. A pair of lenses thus equipped Dr. + Wollaston called the periscopic microscope. Dr. Brewster suggested that in + such a lens the same object might be attained with greater ease by + grinding an equatorial groove about a thick or globular lens and filling + the groove with an opaque cement. This arrangement found much favor, and + came subsequently to be known as a Coddington lens, though Mr. Coddington + laid no claim to being its inventor. + </p> + <p> + Sir John Herschel, another of the very great physicists of the time, also + gave attention to the problem of improving the microscope, and in 1821 he + introduced what was called an aplanatic combination of lenses, in which, + as the name implies, the spherical aberration was largely done away with. + It was thought that the use of this Herschel aplanatic combination as an + eyepiece, combined with the Wollaston doublet for the objective, came as + near perfection as the compound microscope was likely soon to come. But in + reality the instrument thus constructed, though doubtless superior to any + predecessor, was so defective that for practical purposes the simple + microscope, such as the doublet or the Coddington, was preferable to the + more complicated one. + </p> + <p> + Many opticians, indeed, quite despaired of ever being able to make a + satisfactory refracting compound microscope, and some of them had taken up + anew Sir Isaac Newton's suggestion in reference to a reflecting + microscope. In particular, Professor Giovanni Battista Amici, a very + famous mathematician and practical optician of Modena, succeeded in + constructing a reflecting microscope which was said to be superior to any + compound microscope of the time, though the events of the ensuing years + were destined to rob it of all but historical value. For there were + others, fortunately, who did not despair of the possibilities of the + refracting microscope, and their efforts were destined before long to be + crowned with a degree of success not even dreamed of by any preceding + generation. + </p> + <p> + The man to whom chief credit is due for directing those final steps that + made the compound microscope a practical implement instead of a scientific + toy was the English amateur optician Joseph Jackson Lister. Combining + mathematical knowledge with mechanical ingenuity, and having the practical + aid of the celebrated optician Tulley, he devised formulae for the + combination of lenses of crown glass with others of flint glass, so + adjusted that the refractive errors of one were corrected or compensated + by the other, with the result of producing lenses of hitherto unequalled + powers of definition; lenses capable of showing an image highly magnified, + yet relatively free from those distortions and fringes of color that had + heretofore been so disastrous to true interpretation of magnified + structures. + </p> + <p> + Lister had begun his studies of the lens in 1824, but it was not until + 1830 that he contributed to the Royal Society the famous paper detailing + his theories and experiments. Soon after this various continental + opticians who had long been working along similar lines took the matter + up, and their expositions, in particular that of Amici, introduced the + improved compound microscope to the attention of microscopists everywhere. + And it required but the most casual trial to convince the experienced + observers that a new implement of scientific research had been placed in + their hands which carried them a long step nearer the observation of the + intimate physical processes which lie at the foundation of vital + phenomena. For the physiologist this perfection of the compound microscope + had the same significance that the, discovery of America had for the + fifteenth-century geographers—it promised a veritable world of + utterly novel revelations. Nor was the fulfilment of that promise long + delayed. + </p> + <p> + Indeed, so numerous and so important were the discoveries now made in the + realm of minute anatomy that the rise of histology to the rank of an + independent science may be said to date from this period. Hitherto, ever + since the discovery of magnifying-glasses, there had been here and there a + man, such as Leuwenhoek or Malpighi, gifted with exceptional vision, and + perhaps unusually happy in his conjectures, who made important + contributions to the knowledge of the minute structure of organic tissues; + but now of a sudden it became possible for the veriest tyro to confirm or + refute the laborious observations of these pioneers, while the skilled + observer could step easily beyond the barriers of vision that hitherto + were quite impassable. And so, naturally enough, the physiologists of the + fourth decade of the nineteenth century rushed as eagerly into the new + realm of the microscope as, for example, their successors of to-day are + exploring the realm of the X-ray. + </p> + <p> + Lister himself, who had become an eager interrogator of the instrument he + had perfected, made many important discoveries, the most notable being his + final settlement of the long-mooted question as to the true form of the + red corpuscles of the human blood. In reality, as everybody knows + nowadays, these are biconcave disks, but owing to their peculiar figure it + is easily possible to misinterpret the appearances they present when seen + through a poor lens, and though Dr. Thomas Young and various other + observers had come very near the truth regarding them, unanimity of + opinion was possible only after the verdict of the perfected microscope + was given. + </p> + <p> + These blood corpuscles are so infinitesimal in size that something like + five millions of them are found in each cubic millimetre of the blood, yet + they are isolated particles, each having, so to speak, its own + personality. This, of course, had been known to microscopists since the + days of the earliest lenses. It had been noticed, too, by here and there + an observer, that certain of the solid tissues seemed to present something + of a granular texture, as if they, too, in their ultimate constitution, + were made up of particles. And now, as better and better lenses were + constructed, this idea gained ground constantly, though for a time no one + saw its full significance. In the case of vegetable tissues, indeed, the + fact that little particles encased a membranous covering, and called + cells, are the ultimate visible units of structure had long been known. + But it was supposed that animal tissues differed radically from this + construction. The elementary particles of vegetables "were regarded to a + certain extent as individuals which composed the entire plant, while, on + the other hand, no such view was taken of the elementary parts of + animals." + </p> + <p> + ROBERT BROWN AND THE CELL NUCLEUS + </p> + <p> + In the year 1833 a further insight into the nature of the ultimate + particles of plants was gained through the observation of the English + microscopist Robert Brown, who, in the course of his microscopic studies + of the epidermis of orchids, discovered in the cells "an opaque spot," + which he named the nucleus. Doubtless the same "spot" had been seen often + enough before by other observers, but Brown was the first to recognize it + as a component part of the vegetable cell and to give it a name. + </p> + <p> + "I shall conclude my observations on Orchideae," said Brown, "with a + notice of some points of their general structure, which chiefly relate to + the cellular tissue. In each cell of the epidermis of a great part of this + family, especially of those with membranous leaves, a single circular + areola, generally somewhat more opaque than, the membrane of the cell, is + observable. This areola, which is more or less distinctly granular, is + slightly convex, and although it seems to be on the surface is in reality + covered by the outer lamina of the cell. There is no regularity as to its + place in the cell; it is not unfrequently, however, central or nearly so. + </p> + <p> + "As only one areola belongs to each cell, and as in many cases where it + exists in the common cells of the epidermis, it is also visible in the + cutaneous glands or stomata, and in these is always double—one being + on each side of the limb—it is highly probable that the cutaneous + gland is in all cases composed of two cells of peculiar form, the line of + union being the longitudinal axis of the disk or pore. + </p> + <p> + "This areola, or nucleus of the cell as perhaps it might be termed, is not + confined to the epidermis, being also found, not only in the pubescence of + the surface, particularly when jointed, as in cypripedium, but in many + cases in the parenchyma or internal cells of the tissue, especially when + these are free from the deposition of granular matter. + </p> + <p> + "In the compressed cells of the epidermis the nucleus is in a + corresponding degree flattened; but in the internal tissue it is often + nearly spherical, more or less firmly adhering to one of the walls, and + projecting into the cavity of the cell. In this state it may not + unfrequently be found in the substance of the column and in that of the + perianthium. + </p> + <p> + "The nucleus is manifest also in the tissue of the stigma, where in + accordance with the compression of the utriculi, it has an intermediate + form, being neither so much flattened as in the epidermis nor so convex as + it is in the internal tissue of the column. + </p> + <p> + "I may here remark that I am acquainted with one case of apparent + exception to the nucleus being solitary in each utriculus or cell—namely, + in Bletia Tankervilliae. In the utriculi of the stigma of this plant, I + have generally, though not always, found a second areola apparently on the + surface, and composed of much larger granules than the ordinary nucleus, + which is formed of very minute granular matter, and seems to be deep + seated. + </p> + <p> + "Mr. Bauer has represented the tissue of the stigma, in the species of + Bletia, both before and, as he believes, after impregnation; and in the + latter state the utriculi are marked with from one to three areolae of + similar appearance. + </p> + <p> + "The nucleus may even be supposed to exist in the pollen of this family. + In the early stages of its formation, at least a minute areola is of ten + visible in the simple grain, and in each of the constituent parts of cells + of the compound grain. But these areolae may perhaps rather be considered + as merely the points of production of the tubes. + </p> + <p> + "This nucleus of the cell is not confined to orchideae, but is equally + manifest in many other monocotyledonous families; and I have even found + it, hitherto however in very few cases, in the epidermis of dicotyledonous + plants; though in this primary division it may perhaps be said to exist in + the early stages of development of the pollen. Among monocotyledons, the + orders in which it is most remarkable are Liliaceae, Hemerocallideae, + Asphodeleae, Irideae, and Commelineae. + </p> + <p> + "In some plants belonging to this last-mentioned family, especially in + Tradascantia virginica, and several nearly related species, it is + uncommonly distinct, not in the epidermis and in the jointed hairs of the + filaments, but in the tissue of the stigma, in the cells of the ovulum + even before impregnation, and in all the stages of formation of the grains + of pollen, the evolution of which is so remarkable in tradascantia. + </p> + <p> + "The few indications of the presence of this nucleus, or areola, that I + have hitherto met with in the publications of botanists are chiefly in + some figures of epidermis, in the recent works of Meyen and Purkinje, and + in one case, in M. Adolphe Broigniart's memoir on the structure of leaves. + But so little importance seems to be attached to it that the appearance is + not always referred to in the explanations of the figures in which it is + represented. Mr. Bauer, however, who has also figured it in the utriculi + of the stigma of Bletia Tankervilliae has more particularly noticed it, + and seems to consider it as only visible after impregnation."(2) + </p> + <p> + SCHLEIDEN AND SCHWANN AND THE CELL THEORY + </p> + <p> + That this newly recognized structure must be important in the economy of + the cell was recognized by Brown himself, and by the celebrated German + Meyen, who dealt with it in his work on vegetable physiology, published + not long afterwards; but it remained for another German, the professor of + botany in the University of Jena, Dr. M. J. Schleiden, to bring the + nucleus to popular attention, and to assert its all-importance in the + economy of the cell. + </p> + <p> + Schleiden freely acknowledged his indebtedness to Brown for first + knowledge of the nucleus, but he soon carried his studies of that + structure far beyond those of its discoverer. He came to believe that the + nucleus is really the most important portion of the cell, in that it is + the original structure from which the remainder of the cell is developed. + Hence he named it the cytoblast. He outlined his views in an epochal paper + published in Muller's Archives in 1838, under title of "Beitrage zur + Phytogenesis." This paper is in itself of value, yet the most important + outgrowth of Schleiden's observations of the nucleus did not spring from + his own labors, but from those of a friend to whom he mentioned his + discoveries the year previous to their publication. This friend was Dr. + Theodor Schwann, professor of physiology in the University of Louvain. + </p> + <p> + At the moment when these observations were communicated to him Schwann was + puzzling over certain details of animal histology which he could not + clearly explain. His great teacher, Johannes Muller, had called attention + to the strange resemblance to vegetable cells shown by certain cells of + the chorda dorsalis (the embryonic cord from which the spinal column is + developed), and Schwann himself had discovered a corresponding similarity + in the branchial cartilage of a tadpole. Then, too, the researches of + Friedrich Henle had shown that the particles that make up the epidermis of + animals are very cell-like in appearance. Indeed, the cell-like character + of certain animal tissues had come to be matter of common note among + students of minute anatomy. Schwann felt that this similarity could not be + mere coincidence, but he had gained no clew to further insight until + Schleiden called his attention to the nucleus. Then at once he reasoned + that if there really is the correspondence between vegetable and animal + tissues that he suspected, and if the nucleus is so important in the + vegetable cell as Schleiden believed, the nucleus should also be found in + the ultimate particles of animal tissues. + </p> + <p> + Schwann's researches soon showed the entire correctness of this + assumption. A closer study of animal tissues under the microscope showed, + particularly in the case of embryonic tissues, that "opaque spots" such as + Schleiden described are really to be found there in abundance—forming, + indeed, a most characteristic phase of the structure. The location of + these nuclei at comparatively regular intervals suggested that they are + found in definite compartments of the tissue, as Schleiden had shown to be + the case with vegetables; indeed, the walls that separated such cell-like + compartments one from another were in some cases visible. Particularly was + this found to be the case with embryonic tissues, and the study of these + soon convinced Schwann that his original surmise had been correct, and + that all animal tissues are in their incipiency composed of particles not + unlike the ultimate particles of vegetables in short, of what the + botanists termed cells. Adopting this name, Schwann propounded what soon + became famous as his cell theory, under title of Mikroskopische + Untersuchungen uber die Ubereinstimmung in der Structur und dent Wachsthum + der Thiere und Pflanzen. So expeditious had been his work that this book + was published early in 1839, only a few months after the appearance of + Schleiden's paper. + </p> + <p> + As the title suggests, the main idea that actuated Schwann was to unify + vegetable and animal tissues. Accepting cell-structure as the basis of all + vegetable tissues, he sought to show that the same is true of animal + tissues, all the seeming diversities of fibre being but the alteration and + development of what were originally simple cells. And by cell Schwann + meant, as did Schleiden also, what the word ordinarily implies—a + cavity walled in on all sides. He conceived that the ultimate constituents + of all tissues were really such minute cavities, the most important part + of which was the cell wall, with its associated nucleus. He knew, indeed, + that the cell might be filled with fluid contents, but he regarded these + as relatively subordinate in importance to the wall itself. This, however, + did not apply to the nucleus, which was supposed to lie against the cell + wall and in the beginning to generate it. Subsequently the wall might grow + so rapidly as to dissociate itself from its contents, thus becoming a + hollow bubble or true cell; but the nucleus, as long as it lasted, was + supposed to continue in contact with the cell wall. Schleiden had even + supposed the nucleus to be a constituent part of the wall, sometimes lying + enclosed between two layers of its substance, and Schwann quoted this view + with seeming approval. Schwann believed, however, that in the mature cell + the nucleus ceased to be functional and disappeared. + </p> + <p> + The main thesis as to the similarity of development of vegetable and + animal tissues and the cellular nature of the ultimate constitution of + both was supported by a mass of carefully gathered evidence which a + multitude of microscopists at once confirmed, so Schwann's work became a + classic almost from the moment of its publication. Of course various other + workers at once disputed Schwann's claim to priority of discovery, in + particular the English microscopist Valentin, who asserted, not without + some show of justice, that he was working closely along the same lines. + Put so, for that matter, were numerous others, as Henle, Turpin, + Du-mortier, Purkinje, and Muller, all of whom Schwann himself had quoted. + Moreover, there were various physiologists who earlier than any of these + had foreshadowed the cell theory—notably Kaspar Friedrich Wolff, + towards the close of the previous century, and Treviranus about 1807, But, + as we have seen in so many other departments of science, it is one thing + to foreshadow a discovery, it is quite another to give it full expression + and make it germinal of other discoveries. And when Schwann put forward + the explicit claim that "there is one universal principle of development + for the elementary parts, of organisms, however different, and this + principle is the formation of cells," he enunciated a doctrine which was + for all practical purposes absolutely new and opened up a novel field for + the microscopist to enter. A most important era in physiology dates from + the publication of his book in 1839. + </p> + <p> + THE CELL THEORY ELABORATED + </p> + <p> + That Schwann should have gone to embryonic tissues for the establishment + of his ideas was no doubt due very largely to the influence of the great + Russian Karl Ernst von Baer, who about ten years earlier had published the + first part of his celebrated work on embryology, and whose ideas were + rapidly gaining ground, thanks largely to the advocacy of a few men, + notably Johannes Muller, in Germany, and William B. Carpenter, in England, + and to the fact that the improved microscope had made minute anatomy + popular. Schwann's researches made it plain that the best field for the + study of the animal cell is here, and a host of explorers entered the + field. The result of their observations was, in the main, to confirm the + claims of Schwann as to the universal prevalence of the cell. The + long-current idea that animal tissues grow only as a sort of deposit from + the blood-vessels was now discarded, and the fact of so-called plantlike + growth of animal cells, for which Schwann contended, was universally + accepted. Yet the full measure of the affinity between the two classes of + cells was not for some time generally apprehended. + </p> + <p> + Indeed, since the substance that composes the cell walls of plants is + manifestly very different from the limiting membrane of the animal cell, + it was natural, so long as the wall was considered the most essential part + of the structure, that the divergence between the two classes of cells + should seem very pronounced. And for a time this was the conception of the + matter that was uniformly accepted. But as time went on many observers had + their attention called to the peculiar characteristics of the contents of + the cell, and were led to ask themselves whether these might not be more + important than had been supposed. In particular, Dr. Hugo von Mohl, + professor of botany in the University of Tubingen, in the course of his + exhaustive studies of the vegetable cell, was impressed with the peculiar + and characteristic appearance of the cell contents. He observed + universally within the cell "an opaque, viscid fluid, having granules + intermingled in it," which made up the main substance of the cell, and + which particularly impressed him because under certain conditions it could + be seen to be actively in motion, its parts separated into filamentous + streams. + </p> + <p> + Von Mohl called attention to the fact that this motion of the cell + contents had been observed as long ago as 1774 by Bonaventura Corti, and + rediscovered in 1807 by Treviranus, and that these observers had described + the phenomenon under the "most unsuitable name of 'rotation of the cell + sap.'" Von Mohl recognized that the streaming substance was something + quite different from sap. He asserted that the nucleus of the cell lies + within this substance and not attached to the cell wall as Schleiden had + contended. He saw, too, that the chlorophyl granules, and all other of the + cell contents, are incorporated with the "opaque, viscid fluid," and in + 1846 he had become so impressed with the importance of this universal cell + substance that he gave it the name of protoplasm. Yet in so doing he had + no intention of subordinating the cell wall. The fact that Payen, in 1844, + had demonstrated that the cell walls of all vegetables, high or low, are + composed largely of one substance, cellulose, tended to strengthen the + position of the cell wall as the really essential structure, of which the + protoplasmic contents were only subsidiary products. + </p> + <p> + Meantime, however, the students of animal histology were more and more + impressed with the seeming preponderance of cell contents over cell walls + in the tissues they studied. They, too, found the cell to be filled with a + viscid, slimy fluid capable of motion. To this Dujardin gave the name of + sarcode. Presently it came to be known, through the labors of Kolliker, + Nageli, Bischoff, and various others, that there are numerous lower forms + of animal life which seem to be composed of this sarcode, without any cell + wall whatever. The same thing seemed to be true of certain cells of higher + organisms, as the blood corpuscles. Particularly in the case of cells that + change their shape markedly, moving about in consequence of the streaming + of their sarcode, did it seem certain that no cell wall is present, or + that, if present, its role must be insignificant. + </p> + <p> + And so histologists came to question whether, after all, the cell contents + rather than the enclosing wall must not be the really essential structure, + and the weight of increasing observations finally left no escape from the + conclusion that such is really the case. But attention being thus + focalized on the cell contents, it was at once apparent that there is a + far closer similarity between the ultimate particles of vegetables and + those of animals than had been supposed. Cellulose and animal membrane + being now regarded as more by-products, the way was clear for the + recognition of the fact that vegetable protoplasm and animal sarcode are + marvellously similar in appearance and general properties. The closer the + observation the more striking seemed this similarity; and finally, about + 1860, it was demonstrated by Heinrich de Bary and by Max Schultze that the + two are to all intents and purposes identical. Even earlier Remak had + reached a similar conclusion, and applied Von Mohl's word protoplasm to + animal cell contents, and now this application soon became universal. + Thenceforth this protoplasm was to assume the utmost importance in the + physiological world, being recognized as the universal "physical basis of + life," vegetable and animal alike. This amounted to the logical extension + and culmination of Schwann's doctrine as to the similarity of development + of the two animate kingdoms. Yet at the same time it was in effect the + banishment of the cell that Schwann had defined. The word cell was + retained, it is true, but it no longer signified a minute cavity. It now + implied, as Schultze defined it, "a small mass of protoplasm endowed with + the attributes of life." This definition was destined presently to meet + with yet another modification, as we shall see; but the conception of the + protoplasmic mass as the essential ultimate structure, which might or + might not surround itself with a protective covering, was a permanent + addition to physiological knowledge. The earlier idea had, in effect, + declared the shell the most important part of the egg; this developed view + assigned to the yolk its true position. + </p> + <p> + In one other important regard the theory of Schleiden and Schwann now + became modified. This referred to the origin of the cell. Schwann had + regarded cell growth as a kind of crystallization, beginning with the + deposit of a nucleus about a granule in the intercellular substance—the + cytoblastema, as Schleiden called it. But Von Mohl, as early as 1835, had + called attention to the formation of new vegetable cells through the + division of a pre-existing cell. Ehrenberg, another high authority of the + time, contended that no such division occurs, and the matter was still in + dispute when Schleiden came forward with his discovery of so-called free + cell-formation within the parent cell, and this for a long time diverted + attention from the process of division which Von Mohl had described. All + manner of schemes of cell-formation were put forward during the ensuing + years by a multitude of observers, and gained currency notwithstanding Von + Mohl's reiterated contention that there are really but two ways in which + the formation of new cells takes place—namely, "first, through + division of older cells; secondly, through the formation of secondary + cells lying free in the cavity of a cell." + </p> + <p> + But gradually the researches of such accurate observers as Unger, Nageli, + Kolliker, Reichart, and Remak tended to confirm the opinion of Von Mohl + that cells spring only from cells, and finally Rudolf Virchow brought the + matter to demonstration about 1860. His Omnis cellula e cellula became + from that time one of the accepted data of physiology. This was + supplemented a little later by Fleming's Omnis nucleus e nucleo, when + still more refined methods of observation had shown that the part of the + cell which always first undergoes change preparatory to new cell-formation + is the all-essential nucleus. Thus the nucleus was restored to the + important position which Schwann and Schleiden had given it, but with + greatly altered significance. Instead of being a structure generated de + novo from non-cellular substance, and disappearing as soon as its function + of cell-formation was accomplished, the nucleus was now known as the + central and permanent feature of every cell, indestructible while the cell + lives, itself the division-product of a pre-existing nucleus, and the + parent, by division of its substance, of other generations of nuclei. The + word cell received a final definition as "a small mass of protoplasm + supplied with a nucleus." + </p> + <p> + In this widened and culminating general view of the cell theory it became + clear that every animate organism, animal or vegetable, is but a cluster + of nucleated cells, all of which, in each individual case, are the direct + descendants of a single primordial cell of the ovum. In the developed + individuals of higher organisms the successive generations of cells become + marvellously diversified in form and in specific functions; there is a + wonderful division of labor, special functions being chiefly relegated to + definite groups of cells; but from first to last there is no function + developed that is not present, in a primitive way, in every cell, however + isolated; nor does the developed cell, however specialized, ever forget + altogether any one of its primordial functions or capacities. All + physiology, then, properly interpreted, becomes merely a study of cellular + activities; and the development of the cell theory takes its place as the + great central generalization in physiology of the nineteenth century. + Something of the later developments of this theory we shall see in another + connection. + </p> + <p> + ANIMAL CHEMISTRY + </p> + <p> + Just at the time when the microscope was opening up the paths that were to + lead to the wonderful cell theory, another novel line of interrogation of + the living organism was being put forward by a different set of observers. + Two great schools of physiological chemistry had arisen—one under + guidance of Liebig and Wohler, in Germany, the other dominated by the + great French master Jean Baptiste Dumas. Liebig had at one time + contemplated the study of medicine, and Dumas had achieved distinction in + connection with Prevost, at Geneva, in the field of pure physiology before + he turned his attention especially to chemistry. Both these masters, + therefore, and Wohler as well, found absorbing interest in those phases of + chemistry that have to do with the functions of living tissues; and it was + largely through their efforts and the labors of their followers that the + prevalent idea that vital processes are dominated by unique laws was + discarded and physiology was brought within the recognized province of the + chemist. So at about the time when the microscope had taught that the cell + is the really essential structure of the living organism, the chemists had + come to understand that every function of the organism is really the + expression of a chemical change—that each cell is, in short, a + miniature chemical laboratory. And it was this combined point of view of + anatomist and chemist, this union of hitherto dissociated forces, that + made possible the inroads into the unexplored fields of physiology that + were effected towards the middle of the nineteenth century. + </p> + <p> + One of the first subjects reinvestigated and brought to proximal solution + was the long-mooted question of the digestion of foods. Spallanzani and + Hunter had shown in the previous century that digestion is in some sort a + solution of foods; but little advance was made upon their work until 1824, + when Prout detected the presence of hydrochloric acid in the gastric + juice. A decade later Sprott and Boyd detected the existence of peculiar + glands in the gastric mucous membrane; and Cagniard la Tour and Schwann + independently discovered that the really active principle of the gastric + juice is a substance which was named pepsin, and which was shown by + Schwann to be active in the presence of hydrochloric acid. + </p> + <p> + Almost coincidently, in 1836, it was discovered by Purkinje and Pappenheim + that another organ than the stomach—namely, the pancreas—has a + share in digestion, and in the course of the ensuing decade it came to be + known, through the efforts of Eberle, Valentin, and Claude Bernard, that + this organ is all-important in the digestion of starchy and fatty foods. + It was found, too, that the liver and the intestinal glands have each an + important share in the work of preparing foods for absorption, as also has + the saliva—that, in short, a coalition of forces is necessary for + the digestion of all ordinary foods taken into the stomach. + </p> + <p> + And the chemists soon discovered that in each one of the essential + digestive juices there is at least one substance having certain + resemblances to pepsin, though acting on different kinds of food. The + point of resemblance between all these essential digestive agents is that + each has the remarkable property of acting on relatively enormous + quantities of the substance which it can digest without itself being + destroyed or apparently even altered. In virtue of this strange property, + pepsin and the allied substances were spoken of as ferments, but more + recently it is customary to distinguish them from such organized ferments + as yeast by designating them enzymes. The isolation of these enzymes, and + an appreciation of their mode of action, mark a long step towards the + solution of the riddle of digestion, but it must be added that we are + still quite in the dark as to the real ultimate nature of their strange + activity. + </p> + <p> + In a comprehensive view, the digestive organs, taken as a whole, are a + gateway between the outside world and the more intimate cells of the + organism. Another equally important gateway is furnished by the lungs, and + here also there was much obscurity about the exact method of functioning + at the time of the revival of physiological chemistry. That oxygen is + consumed and carbonic acid given off during respiration the chemists of + the age of Priestley and Lavoisier had indeed made clear, but the mistaken + notion prevailed that it was in the lungs themselves that the important + burning of fuel occurs, of which carbonic acid is a chief product. But now + that attention had been called to the importance of the ultimate cell, + this misconception could not long hold its ground, and as early as 1842 + Liebig, in the course of his studies of animal heat, became convinced that + it is not in the lungs, but in the ultimate tissues to which they are + tributary, that the true consumption of fuel takes place. Reviving + Lavoisier's idea, with modifications and additions, Liebig contended, and + in the face of opposition finally demonstrated, that the source of animal + heat is really the consumption of the fuel taken in through the stomach + and the lungs. He showed that all the activities of life are really the + product of energy liberated solely through destructive processes, + amounting, broadly speaking, to combustion occurring in the ultimate cells + of the organism. Here is his argument: + </p> + <p> + LIEBIG ON ANIMAL HEAT + </p> + <p> + "The oxygen taken into the system is taken out again in the same forms, + whether in summer or in winter; hence we expire more carbon in cold + weather, and when the barometer is high, than we do in warm weather; and + we must consume more or less carbon in our food in the same proportion; in + Sweden more than in Sicily; and in our more temperate climate a full + eighth more in winter than in summer. + </p> + <p> + "Even when we consume equal weights of food in cold and warm countries, + infinite wisdom has so arranged that the articles of food in different + climates are most unequal in the proportion of carbon they contain. The + fruits on which the natives of the South prefer to feed do not in the + fresh state contain more than twelve per cent. of carbon, while the + blubber and train-oil used by the inhabitants of the arctic regions + contain from sixty-six to eighty per cent. of carbon. + </p> + <p> + "It is no difficult matter, in warm climates, to study moderation in + eating, and men can bear hunger for a long time under the equator; but + cold and hunger united very soon exhaust the body. + </p> + <p> + "The mutual action between the elements of the food and the oxygen + conveyed by the circulation of the blood to every part of the body is the + source of animal heat. + </p> + <p> + "All living creatures whose existence depends on the absorption of oxygen + possess within themselves a source of heat independent of surrounding + objects. + </p> + <p> + "This truth applies to all animals, and extends besides to the germination + of seeds, to the flowering of plants, and to the maturation of fruits. It + is only in those parts of the body to which arterial blood, and with it + the oxygen absorbed in respiration, is conveyed that heat is produced. + Hair, wool, or feathers do not possess an elevated temperature. This high + temperature of the animal body, or, as it may be called, disengagement of + heat, is uniformly and under all circumstances the result of the + combination of combustible substance with oxygen. + </p> + <p> + "In whatever way carbon may combine with oxygen, the act of combination + cannot take place without the disengagement of heat. It is a matter of + indifference whether the combination takes place rapidly or slowly, at a + high or at a low temperature; the amount of heat liberated is a constant + quantity. The carbon of the food, which is converted into carbonic acid + within the body, must give out exactly as much heat as if it had been + directly burned in the air or in oxygen gas; the only difference is that + the amount of heat produced is diffused over unequal times. In oxygen the + combustion is more rapid and the heat more intense; in air it is slower, + the temperature is not so high, but it continues longer. + </p> + <p> + "It is obvious that the amount of heat liberated must increase or diminish + with the amount of oxygen introduced in equal times by respiration. Those + animals which respire frequently, and consequently consume much oxygen, + possess a higher temperature than others which, with a body of equal size + to be heated, take into the system less oxygen. The temperature of a child + (102 degrees) is higher than that of an adult (99.5 degrees). That of + birds (104 to 105.4 degrees) is higher than that of quadrupeds (98.5 to + 100.4 degrees), or than that of fishes or amphibia, whose proper + temperature is from 3.7 to 2.6 degrees higher than that of the medium in + which they live. All animals, strictly speaking, are warm-blooded; but in + those only which possess lungs is the temperature of the body independent + of the surrounding medium. + </p> + <p> + "The most trustworthy observations prove that in all climates, in the + temperate zones as well as at the equator or the poles, the temperature of + the body in man, and of what are commonly called warm-blooded animals, is + invariably the same; yet how different are the circumstances in which they + live. + </p> + <p> + "The animal body is a heated mass, which bears the same relation to + surrounding objects as any other heated mass. It receives heat when the + surrounding objects are hotter, it loses heat when they are colder than + itself. We know that the rapidity of cooling increases with the difference + between the heated body and that of the surrounding medium—that is, + the colder the surrounding medium the shorter the time required for the + cooling of the heated body. How unequal, then, must be the loss of heat of + a man at Palermo, where the actual temperature is nearly equal to that of + the body, and in the polar regions, where the external temperature is from + 70 to 90 degrees lower. + </p> + <p> + "Yet notwithstanding this extremely unequal loss of heat, experience has + shown that the blood of an inhabitant of the arctic circle has a + temperature as high as that of the native of the South, who lives in so + different a medium. This fact, when its true significance is perceived, + proves that the heat given off to the surrounding medium is restored + within the body with great rapidity. This compensation takes place more + rapidly in winter than in summer, at the pole than at the equator. + </p> + <p> + "Now in different climates the quantity of oxygen introduced into the + system of respiration, as has been already shown, varies according to the + temperature of the external air; the quantity of inspired oxygen increases + with the loss of heat by external cooling, and the quantity of carbon or + hydrogen necessary to combine with this oxygen must be increased in like + ratio. It is evident that the supply of heat lost by cooling is effected + by the mutual action of the elements of the food and the inspired oxygen, + which combine together. To make use of a familiar, but not on that account + a less just illustration, the animal body acts, in this respect, as a + furnace, which we supply with fuel. It signifies nothing what intermediate + forms food may assume, what changes it may undergo in the body, the last + change is uniformly the conversion of carbon into carbonic acid and of its + hydrogen into water; the unassimilated nitrogen of the food, along with + the unburned or unoxidized carbon, is expelled in the excretions. In order + to keep up in a furnace a constant temperature, we must vary the supply of + fuel according to the external temperature—that is, according to the + supply of oxygen. + </p> + <p> + "In the animal body the food is the fuel; with a proper supply of oxygen + we obtain the heat given out during its oxidation or combustion."(3) + </p> + <p> + BLOOD CORPUSCLES, MUSCLES, AND GLANDS + </p> + <p> + Further researches showed that the carriers of oxygen, from the time of + its absorption in the lungs till its liberation in the ultimate tissues, + are the red corpuscles, whose function had been supposed to be the + mechanical one of mixing of the blood. It transpired that the red + corpuscles are composed chiefly of a substance which Kuhne first isolated + in crystalline form in 1865, and which was named haemoglobin—a + substance which has a marvellous affinity for oxygen, seizing on it + eagerly at the lungs vet giving it up with equal readiness when coursing + among the remote cells of the body. When freighted with oxygen it becomes + oxyhaemoglobin and is red in color; when freed from its oxygen it takes a + purple hue; hence the widely different appearance of arterial and venous + blood, which so puzzled the early physiologists. + </p> + <p> + This proof of the vitally important role played by the red-blood + corpuscles led, naturally, to renewed studies of these infinitesimal + bodies. It was found that they may vary greatly in number at different + periods in the life of the same individual, proving that they may be both + developed and destroyed in the adult organism. Indeed, extended + observations left no reason to doubt that the process of corpuscle + formation and destruction may be a perfectly normal one—that, in + short, every red-blood corpuscle runs its course and dies like any more + elaborate organism. They are formed constantly in the red marrow of bones, + and are destroyed in the liver, where they contribute to the formation of + the coloring matter of the bile. Whether there are other seats of such + manufacture and destruction of the corpuscles is not yet fully determined. + Nor are histologists agreed as to whether the red-blood corpuscles + themselves are to be regarded as true cells, or merely as fragments of + cells budded out from a true cell for a special purpose; but in either + case there is not the slightest doubt that the chief function of the red + corpuscle is to carry oxygen. + </p> + <p> + If the oxygen is taken to the ultimate cells before combining with the + combustibles it is to consume, it goes without saying that these + combustibles themselves must be carried there also. Nor could it be in + doubt that the chiefest of these ultimate tissues, as regards, quantity of + fuel required, are the muscles. A general and comprehensive view of the + organism includes, then, digestive apparatus and lungs as the channels of + fuel-supply; blood and lymph channels as the transportation system; and + muscle cells, united into muscle fibres, as the consumption furnaces, + where fuel is burned and energy transformed and rendered available for the + purposes of the organism, supplemented by a set of excretory organs, + through which the waste products—the ashes—are eliminated from + the system. + </p> + <p> + But there remain, broadly speaking, two other sets of organs whose size + demonstrates their importance in the economy of the organism, yet whose + functions are not accounted for in this synopsis. These are those + glandlike organs, such as the spleen, which have no ducts and produce no + visible secretions, and the nervous mechanism, whose central organs are + the brain and spinal cord. What offices do these sets of organs perform in + the great labor-specializing aggregation of cells which we call a living + organism? + </p> + <p> + As regards the ductless glands, the first clew to their function was given + when the great Frenchman Claude Bernard (the man of whom his admirers + loved to say, "He is not a physiologist merely; he is physiology itself") + discovered what is spoken of as the glycogenic function of the liver. The + liver itself, indeed, is not a ductless organ, but the quantity of its + biliary output seems utterly disproportionate to its enormous size, + particularly when it is considered that in the case of the human species + the liver contains normally about one-fifth of all the blood in the entire + body. Bernard discovered that the blood undergoes a change of composition + in passing through the liver. The liver cells (the peculiar forms of which + had been described by Purkinje, Henle, and Dutrochet about 1838) have the + power to convert certain of the substances that come to them into a + starchlike compound called glycogen, and to store this substance away till + it is needed by the organism. This capacity of the liver cells is quite + independent of the bile-making power of the same cells; hence the + discovery of this glycogenic function showed that an organ may have more + than one pronounced and important specific function. But its chief + importance was in giving a clew to those intermediate processes between + digestion and final assimilation that are now known to be of such vital + significance in the economy of the organism. + </p> + <p> + In the forty odd years that have elapsed since this pioneer observation of + Bernard, numerous facts have come to light showing the extreme importance + of such intermediate alterations of food-supplies in the blood as that + performed by the liver. It has been shown that the pancreas, the spleen, + the thyroid gland, the suprarenal capsules are absolutely essential, each + in its own way, to the health of the organism, through metabolic changes + which they alone seem capable of performing; and it is suspected that + various other tissues, including even the muscles themselves, have + somewhat similar metabolic capacities in addition to their recognized + functions. But so extremely intricate is the chemistry of the substances + involved that in no single case has the exact nature of the metabolisms + wrought by these organs been fully made out. Each is in its way a chemical + laboratory indispensable to the right conduct of the organism, but the + precise nature of its operations remains inscrutable. The vast importance + of the operations of these intermediate organs is unquestioned. + </p> + <p> + A consideration of the functions of that other set of organs known + collectively as the nervous system is reserved for a later chapter. + </p> + <p> + <a name="link2H_4_0007" id="link2H_4_0007"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VI. THEORIES OF ORGANIC EVOLUTION + </h2> + <h3> + GOETHE AND THE METAMORPHOSIS OF PARTS + </h3> + <p> + When Coleridge said of Humphry Davy that he might have been the greatest + poet of his time had he not chosen rather to be the greatest chemist, it + is possible that the enthusiasm of the friend outweighed the caution of + the critic. But however that may be, it is beyond dispute that the man who + actually was the greatest poet of that time might easily have taken the + very highest rank as a scientist had not the muse distracted his + attention. Indeed, despite these distractions, Johann Wolfgang von Goethe + achieved successes in the field of pure science that would insure + permanent recognition for his name had he never written a stanza of + poetry. Such is the versatility that marks the highest genius. + </p> + <p> + It was in 1790 that Goethe published the work that laid the foundations of + his scientific reputation—the work on the Metamorphoses of Plants, + in which he advanced the novel doctrine that all parts of the flower are + modified or metamorphosed leaves. + </p> + <p> + "Every one who observes the growth of plants, even superficially," wrote + Goethe, "will notice that certain external parts of them become + transformed at times and go over into the forms of the contiguous parts, + now completely, now to a greater or less degree. Thus, for example, the + single flower is transformed into a double one when, instead of stamens, + petals are developed, which are either exactly like the other petals of + the corolla in form, and color or else still bear visible signs of their + origin. + </p> + <p> + "When we observe that it is possible for a plant in this way to take a + step backward, we shall give so much the more heed to the regular course + of nature and learn the laws of transformation according to which she + produces one part through another, and displays the most varying forms + through the modification of one single organ. + </p> + <p> + "Let us first direct our attention to the plant at the moment when it + develops out of the seed-kernel. The first organs of its upward growth are + known by the name of cotyledons; they have also been called seed-leaves. + </p> + <p> + "They often appear shapeless, filled with new matter, and are just as + thick as they are broad. Their vessels are unrecognizable and are hardly + to be distinguished from the mass of the whole; they bear almost no + resemblance to a leaf, and we could easily be misled into regarding them + as special organs. Occasionally, however, they appear as real leaves, + their vessels are capable of the most minute development, their similarity + to the following leaves does not permit us to take them for special + organs, but we recognize them instead to be the first leaves of the stalk. + </p> + <p> + "The cotyledons are mostly double, and there is an observation to be made + here which will appear still more important as we proceed—that is, + that the leaves of the first node are often paired, even when the + following leaves of the stalk stand alternately upon it. Here we see an + approximation and a joining of parts which nature afterwards separates and + places at a distance from one another. It is still more remarkable when + the cotyledons take the form of many little leaves gathered about an axis, + and the stalk which grows gradually from their midst produces the + following leaves arranged around it singly in a whorl. This may be + observed very exactly in the growth of the pinus species. Here a corolla + of needles forms at the same time a calyx, and we shall have occasion to + remember the present case in connection with similar phenomena later. + </p> + <p> + "On the other hand, we observe that even the cotyledons which are most + like a leaf when compared with the following leaves of the stalk are + always more undeveloped or less developed. This is chiefly noticeable in + their margin which is extremely simple and shows few traces of + indentation. + </p> + <p> + "A few or many of the next following leaves are often already present in + the seed, and lie enclosed between the cotyledons; in their folded state + they are known by the name of plumules. Their form, as compared with the + cotyledons and the following leaves, varies in different plants. Their + chief point of variance, however, from the cotyledons is that they are + flat, delicate, and formed like real leaves generally. They are wholly + green, rest on a visible node, and can no longer deny their relationship + to the following leaves of the stalk, to which, however, they are usually + still inferior, in so far as that their margin is not completely + developed. + </p> + <p> + "The further development, however, goes on ceaselessly in the leaf, from + node to node; its midrib is elongated, and more or less additional ribs + stretch out from this towards the sides. The leaves now appear notched, + deeply indented, or composed of several small leaves, in which last case + they seem to form complete little branches. The date-palm furnishes a + striking example of such a successive transformation of the simplest leaf + form. A midrib is elongated through a succession of several leaves, the + single fan-shaped leaf becomes torn and diverted, and a very complicated + leaf is developed, which rivals a branch in form. + </p> + <p> + "The transition to inflorescence takes place more or less rapidly. In the + latter case we usually observe that the leaves of the stalk loose their + different external divisions, and, on the other hand, spread out more or + less in their lower parts where they are attached to the stalk. If the + transition takes place rapidly, the stalk, suddenly become thinner and + more elongated since the node of the last-developed leaf, shoots up and + collects several leaves around an axis at its end. + </p> + <p> + "That the petals of the calyx are precisely the same organs which have + hitherto appeared as leaves on the stalk, but now stand grouped about a + common centre in an often very different form, can, as it seems to me, be + most clearly demonstrated. Already in connection with the cotyledons + above, we noticed a similar working of nature. The first species, while + they are developing out of the seed-kernel, display a radiate crown of + unmistakable needles; and in the first childhood of these plants we see + already indicated that force of nature whereby when they are older their + flowering and fruit-giving state will be produced. + </p> + <p> + "We see this force of nature, which collects several leaves around an + axis, produce a still closer union and make these approximated, modified + leaves still more unrecognizable by joining them together either wholly or + partially. The bell-shaped or so-called one-petalled calices represent + these cloudy connected leaves, which, being more or less indented from + above, or divided, plainly show their origin. + </p> + <p> + "We can observe the transition from the calyx to the corolla in more than + one instance, for, although the color of the calyx is still usually green, + and like the color of the leaves of the stalk, it nevertheless often + varies in one or another of its parts—at the tips, the margins, the + back, or even, the inward side—while the outer still remains on + green. + </p> + <p> + "The relationship of the corolla to the leaves of the stalk is shown in + more than one way, since on the stalks of some plants appear leaves which + are already more or less colored long before they approach inflorescence; + others are fully colored when near inflorescence. Nature also goes over at + once to the corolla, sometimes by skipping over the organs of the calyx, + and in such a case we likewise have an opportunity to observe that leaves + of the stalk become transformed into petals. Thus on the stalk of tulips, + for instance, there sometimes appears an almost completely developed and + colored petal. Even more remarkable is the case when such a leaf, half + green and half of it belonging to the stalk, remains attached to the + latter, while another colored part is raised with the corolla, and the + leaf is thus torn in two. + </p> + <p> + "The relationship between the petals and stamens is very close. In some + instances nature makes the transition regular—e.g., among the Canna + and several plants of the same family. A true, little-modified petal is + drawn together on its upper margin, and produces a pollen sac, while the + rest of the petal takes the place of the stamen. In double flowers we can + observe this transition in all its stages. In several kinds of roses, + within the fully developed and colored petals there appear other ones + which are drawn together in the middle or on the side. This drawing + together is produced by a small weal, which appears as a more or less + complete pollen sac, and in the same proportion the leaf approaches the + simple form of a stamen. + </p> + <p> + "The pistil in many cases looks almost like a stamen without anthers, and + the relationship between the formation of the two is much closer than + between the other parts. In retrograde fashion nature often produces cases + where the style and stigma (Narben) become retransformed into petals—that + is, the Ranunculus Asiaticus becomes double by transforming the stigma and + style of the fruit-receptacle into real petals, while the stamens are + often found unchanged immediately behind the corolla. + </p> + <p> + "In the seed receptacles, in spite of their formation, of their special + object, and of their method of being joined together, we cannot fail to + recognize the leaf form. Thus, for instance, the pod would be a simple + leaf folded and grown together on its margin; the siliqua would consist of + more leaves folded over another; the compound receptacles would be + explained as being several leaves which, being united above one centre, + keep their inward parts separate and are joined on their margins. We can + convince ourselves of this by actual sight when such composite capsules + fall apart after becoming ripe, because then every part displays an opened + pod."(1) + </p> + <p> + The theory thus elaborated of the metamorphosis of parts was presently + given greater generality through extension to the animal kingdom, in the + doctrine which Goethe and Oken advanced independently, that the vertebrate + skull is essentially a modified and developed vertebra. These were + conceptions worthy of a poet—impossible, indeed, for any mind that + had not the poetic faculty of correlation. But in this case the poet's + vision was prophetic of a future view of the most prosaic science. The + doctrine of metamorphosis of parts soon came to be regarded as of + fundamental importance. + </p> + <p> + But the doctrine had implications that few of its early advocates + realized. If all the parts of a flower—sepal, petal, stamen, pistil, + with their countless deviations of contour and color—are but + modifications of the leaf, such modification implies a marvellous + differentiation and development. To assert that a stamen is a + metamorphosed leaf means, if it means anything, that in the long sweep of + time the leaf has by slow or sudden gradations changed its character + through successive generations, until the offspring, so to speak, of a + true leaf has become a stamen. But if such a metamorphosis as this is + possible—if the seemingly wide gap between leaf and stamen may be + spanned by the modification of a line of organisms—where does the + possibility of modification of organic type find its bounds? Why may not + the modification of parts go on along devious lines until the remote + descendants of an organism are utterly unlike that organism? Why may we + not thus account for the development of various species of beings all + sprung from one parent stock? That, too, is a poet's dream; but is it only + a dream? Goethe thought not. Out of his studies of metamorphosis of parts + there grew in his mind the belief that the multitudinous species of plants + and animals about us have been evolved from fewer and fewer earlier parent + types, like twigs of a giant tree drawing their nurture from the same + primal root. It was a bold and revolutionary thought, and the world + regarded it as but the vagary of a poet. + </p> + <p> + ERASMUS DARWIN + </p> + <p> + Just at the time when this thought was taking form in Goethe's brain, the + same idea was germinating in the mind of another philosopher, an + Englishman of international fame, Dr. Erasmus Darwin, who, while he lived, + enjoyed the widest popularity as a poet, the rhymed couplets of his + Botanic Garden being quoted everywhere with admiration. And posterity + repudiating the verse which makes the body of the book, yet grants + permanent value to the book itself, because, forsooth, its copious + explanatory foot-notes furnish an outline of the status of almost every + department of science of the time. + </p> + <p> + But even though he lacked the highest art of the versifier, Darwin had, + beyond peradventure, the imagination of a poet coupled with profound + scientific knowledge; and it was his poetic insight, correlating organisms + seemingly diverse in structure and imbuing the lowliest flower with a + vital personality, which led him to suspect that there are no lines of + demarcation in nature. "Can it be," he queries, "that one form of organism + has developed from another; that different species are really but modified + descendants of one parent stock?" The alluring thought nestled in his mind + and was nurtured there, and grew in a fixed belief, which was given fuller + expression in his Zoonomia and in the posthumous Temple of Nature. + </p> + <p> + Here is his rendering of the idea as versified in the Temple of Nature: + </p> +<pre xml:space="preserve"> + "Organic life beneath the shoreless waves + Was born, and nursed in Ocean's pearly caves; + First forms minute, unseen by spheric glass, + Move on the mud, or pierce the watery mass; + These, as successive generations bloom, + New powers acquire and larger limbs assume; + Whence countless groups of vegetation spring, + And breathing realms of fin, and feet, and wing. + + "Thus the tall Oak, the giant of the wood, + Which bears Britannia's thunders on the flood; + The Whale, unmeasured monster of the main; + The lordly lion, monarch of the plain; + The eagle, soaring in the realms of air, + Whose eye, undazzled, drinks the solar glare; + Imperious man, who rules the bestial crowd, + Of language, reason, and reflection proud, + With brow erect, who scorns this earthy sod, + And styles himself the image of his God— + Arose from rudiments of form and sense, + An embryon point or microscopic ens!"(2) +</pre> + <p> + Here, clearly enough, is the idea of evolution. But in that day there was + little proof forthcoming of its validity that could satisfy any one but a + poet, and when Erasmus Darwin died, in 1802, the idea of transmutation of + species was still but an unsubstantiated dream. + </p> + <p> + It was a dream, however, which was not confined to Goethe and Darwin. Even + earlier the idea had come more or less vaguely to another great dreamer—and + worker—of Germany, Immanuel Kant, and to several great Frenchmen, + including De Maillet, Maupertuis, Robinet, and the famous naturalist + Buffon—a man who had the imagination of a poet, though his message + was couched in most artistic prose. Not long after the middle of the + eighteenth century Buffon had put forward the idea of transmutation of + species, and he reiterated it from time to time from then on till his + death in 1788. But the time was not yet ripe for the idea of transmutation + of species to burst its bonds. + </p> + <p> + And yet this idea, in a modified or undeveloped form, had taken strange + hold upon the generation that was upon the scene at the close of the + eighteenth century. Vast numbers of hitherto unknown species of animals + had been recently discovered in previously unexplored regions of the + globe, and the wise men were sorely puzzled to account for the disposal of + all of these at the time of the deluge. It simplified matters greatly to + suppose that many existing species had been developed since the episode of + the ark by modification of the original pairs. The remoter bearings of + such a theory were overlooked for the time, and the idea that American + animals and birds, for example, were modified descendants of Old-World + forms—the jaguar of the leopard, the puma of the lion, and so on—became + a current belief with that class of humanity who accept almost any + statement as true that harmonizes with their prejudices without realizing + its implications. + </p> + <p> + Thus it is recorded with eclat that the discovery of the close proximity + of America at the northwest with Asia removes all difficulties as to the + origin of the Occidental faunas and floras, since Oriental species might + easily have found their way to America on the ice, and have been modified + as we find them by "the well-known influence of climate." And the persons + who gave expression to this idea never dreamed of its real significance. + In truth, here was the doctrine of evolution in a nutshell, and, because + its ultimate bearings were not clear, it seemed the most natural of + doctrines. But most of the persons who advanced it would have turned from + it aghast could they have realized its import. As it was, however, only + here and there a man like Buffon reasoned far enough to inquire what might + be the limits of such assumed transmutation; and only here and there a + Darwin or a Goethe reached the conviction that there are no limits. + </p> + <p> + LAMARCK VERSUS CUVIER + </p> + <p> + And even Goethe and Darwin had scarcely passed beyond that tentative stage + of conviction in which they held the thought of transmutation of species + as an ancillary belief not ready for full exposition. There was one of + their contemporaries, however, who, holding the same conception, was moved + to give it full explication. This was the friend and disciple of Buffon, + Jean Baptiste de Lamarck. Possessed of the spirit of a poet and + philosopher, this great Frenchman had also the widest range of technical + knowledge, covering the entire field of animate nature. The first half of + his long life was devoted chiefly to botany, in which he attained high + distinction. Then, just at the beginning of the nineteenth century, he + turned to zoology, in particular to the lower forms of animal life. + Studying these lowly organisms, existing and fossil, he was more and more + impressed with the gradations of form everywhere to be seen; the linking + of diverse families through intermediate ones; and in particular with the + predominance of low types of life in the earlier geological strata. Called + upon constantly to classify the various forms of life in the course of his + systematic writings, he found it more and more difficult to draw sharp + lines of demarcation, and at last the suspicion long harbored grew into a + settled conviction that there is really no such thing as a species of + organism in nature; that "species" is a figment of the human imagination, + whereas in nature there are only individuals. + </p> + <p> + That certain sets of individuals are more like one another than like other + sets is of course patent, but this only means, said Lamarck, that these + similar groups have had comparatively recent common ancestors, while + dissimilar sets of beings are more remotely related in consanguinity. But + trace back the lines of descent far enough, and all will culminate in one + original stock. All forms of life whatsoever are modified descendants of + an original organism. From lowest to highest, then, there is but one race, + one species, just as all the multitudinous branches and twigs from one + root are but one tree. For purposes of convenience of description, we may + divide organisms into orders, families, genera, species, just as we divide + a tree into root, trunk, branches, twigs, leaves; but in the one case, as + in the other, the division is arbitrary and artificial. + </p> + <p> + In Philosophie Zoologique (1809), Lamarck first explicitly formulated his + ideas as to the transmutation of species, though he had outlined them as + early as 1801. In this memorable publication not only did he state his + belief more explicitly and in fuller detail than the idea had been + expressed by any predecessor, but he took another long forward step, + carrying him far beyond all his forerunners except Darwin, in that he made + an attempt to explain the way in which the transmutation of species had + been brought about. The changes have been wrought, he said, through the + unceasing efforts of each organism to meet the needs imposed upon it by + its environment. Constant striving means the constant use of certain + organs. Thus a bird running by the seashore is constantly tempted to wade + deeper and deeper in pursuit of food; its incessant efforts tend to + develop its legs, in accordance with the observed principle that the use + of any organ tends to strengthen and develop it. But such slightly + increased development of the legs is transmitted to the off spring of the + bird, which in turn develops its already improved legs by its individual + efforts, and transmits the improved tendency. Generation after generation + this is repeated, until the sum of the infinitesimal variations, all in + the same direction, results in the production of the long-legged + wading-bird. In a similar way, through individual effort and transmitted + tendency, all the diversified organs of all creatures have been developed—the + fin of the fish, the wing of the bird, the hand of man; nay, more, the + fish itself, the bird, the man, even. Collectively the organs make up the + entire organism; and what is true of the individual organs must be true + also of their ensemble, the living being. + </p> + <p> + Whatever might be thought of Lamarck's explanation of the cause of + transmutation—which really was that already suggested by Erasmus + Darwin—the idea of the evolution for which he contended was but the + logical extension of the conception that American animals are the modified + and degenerated descendants of European animals. But people as a rule are + little prone to follow ideas to their logical conclusions, and in this + case the conclusions were so utterly opposed to the proximal bearings of + the idea that the whole thinking world repudiated them with acclaim. The + very persons who had most eagerly accepted the idea of transmutation of + European species into American species, and similar limited variations + through changed environment, because of the relief thus given the + otherwise overcrowded ark, were now foremost in denouncing such an + extension of the doctrine of transmutation as Lamarck proposed. + </p> + <p> + And, for that matter, the leaders of the scientific world were equally + antagonistic to the Lamarckian hypothesis. Cuvier in particular, once the + pupil of Lamarck, but now his colleague, and in authority more than his + peer, stood out against the transmutation doctrine with all his force. He + argued for the absolute fixity of species, bringing to bear the resources + of a mind which, as a mere repository of facts, perhaps never was + excelled. As a final and tangible proof of his position, he brought + forward the bodies of ibises that had been embalmed by the ancient + Egyptians, and showed by comparison that these do not differ in the + slightest particular from the ibises that visit the Nile to-day. + </p> + <p> + Cuvier's reasoning has such great historical interest—being the + argument of the greatest opponent of evolution of that day—that we + quote it at some length. + </p> + <p> + "The following objections," he says, "have already been started against my + conclusions. Why may not the presently existing races of mammiferous land + quadrupeds be mere modifications or varieties of those ancient races which + we now find in the fossil state, which modifications may have been + produced by change of climate and other local circumstances, and since + raised to the present excessive difference by the operations of similar + causes during a long period of ages? + </p> + <p> + "This objection may appear strong to those who believe in the indefinite + possibility of change of form in organized bodies, and think that, during + a succession of ages and by alterations of habitudes, all the species may + change into one another, or one of them give birth to all the rest. Yet to + these persons the following answer may be given from their own system: If + the species have changed by degrees, as they assume, we ought to find + traces of this gradual modification. Thus, between the palaeotherium and + the species of our own day, we should be able to discover some + intermediate forms; and yet no such discovery has ever been made. Since + the bowels of the earth have not preserved monuments of this strange + genealogy, we have no right to conclude that the ancient and now extinct + species were as permanent in their forms and characters as those which + exist at present; or, at least, that the catastrophe which destroyed them + did not leave sufficient time for the productions of the changes that are + alleged to have taken place. + </p> + <p> + "In order to reply to those naturalists who acknowledge that the varieties + of animals are restrained by nature within certain limits, it would be + necessary to examine how far these limits extend. This is a very curious + inquiry, and in itself exceedingly interesting under a variety of + relations, but has been hitherto very little attended to.... + </p> + <p> + "Wild animals which subsist upon herbage feel the influence of climate a + little more extensively, because there is added to it the influence of + food, both in regard to its abundance and its quality. Thus the elephants + of one forest are larger than those of another; their tusks also grow + somewhat longer in places where their food may happen to be more favorable + for the production of the substance of ivory. The same may take place in + regard to the horns of stags and reindeer. But let us examine two + elephants, the most dissimilar that can be conceived, we shall not + discover the smallest difference in the number and articulations of the + bones, the structure of the teeth, etc......... + </p> + <p> + "Nature appears also to have guarded against the alterations of species + which might proceed from mixture of breeds by influencing the various + species of animals with mutual aversion from one another. Hence all the + cunning and all the force that man is able to exert is necessary to + accomplish such unions, even between species that have the nearest + resemblances. And when the mule breeds that are thus produced by these + forced conjunctions happen to be fruitful, which is seldom the case, this + fecundity never continues beyond a few generations, and would not probably + proceed so far without a continuance of the same cares which excited it at + first. Thus we never see in a wild state intermediate productions between + the hare and the rabbit, between the stag and the doe, or between the + marten and the weasel. But the power of man changes this established + order, and continues to produce all these intermixtures of which the + various species are susceptible, but which they would never produce if + left to themselves. + </p> + <p> + "The degrees of these variations are proportional to the intensity of the + causes that produced them—namely, the slavery or subjection under + which those animals are to man. They do not proceed far in + half-domesticated species. In the cat, for example, a softer or harsher + fur, more brilliant or more varied colors, greater or less size—these + form the whole extent of variety in the species; the skeleton of the cat + of Angora differs in no regular and constant circumstances from the + wild-cat of Europe...." + </p> + <p> + The most remarkable effects of the influence of man are produced upon that + animal which he has reduced most completely under subjection. Dogs have + been transported by mankind into every part of the world and have + submitted their action to his entire direction. Regulated in their unions + by the pleasure or caprice of their masters, the almost endless varieties + of dogs differ from one another in color, in length, and abundance of + hair, which is sometimes entirely wanting; in their natural instincts; in + size, which varies in measure as one to five, mounting in some instances + to more than a hundredfold in bulk; in the form of their ears, noses, and + tails; in the relative length of their legs; in the progressive + development of the brain, in several of the domesticated varieties + occasioning alterations even in the form of the head, some of them having + long, slender muzzles with a flat forehead, others having short muzzles + with a forehead convex, etc., insomuch that the apparent difference + between a mastiff and a water-spaniel and between a greyhound and a pugdog + are even more striking than between almost any of the wild species of a + genus........ + </p> + <p> + It follows from these observations that animals have certain fixed and + natural characters which resist the effects of every kind of influence, + whether proceeding from natural causes or human interference; and we have + not the smallest reason to suspect that time has any more effect on them + than climate. + </p> + <p> + "I am aware that some naturalists lay prodigious stress upon the thousands + which they can call into action by a dash of their pens. In such matters, + however, our only way of judging as to the effects which may be produced + by a long period of time is by multiplying, as it were, such as are + produced by a shorter time. With this view I have endeavored to collect + all the ancient documents respecting the forms of animals; and there are + none equal to those furnished by the Egyptians, both in regard to their + antiquity and abundance. They have not only left us representatives of + animals, but even their identical bodies embalmed and preserved in the + catacombs. + </p> + <p> + "I have examined, with the greatest attention, the engraved figures of + quadrupeds and birds brought from Egypt to ancient Rome, and all these + figures, one with another, have a perfect resemblance to their intended + objects, such as they still are to-day. + </p> + <p> + "From all these established facts, there does not seem to be the smallest + foundation for supposing that the new genera which I have discovered or + established among extraneous fossils, such as the paleoetherium, + anoplotherium, megalonyx, mastodon, pterodactylis, etc., have ever been + the sources of any of our present animals, which only differ so far as + they are influenced by time or climate. Even if it should prove true, + which I am far from believing to be the case, that the fossil elephants, + rhinoceroses, elks, and bears do not differ further from the existing + species of the same genera than the present races of dogs differ among + themselves, this would by no means be a sufficient reason to conclude that + they were of the same species; since the races or varieties of dogs have + been influenced by the trammels of domesticity, which those other animals + never did, and indeed never could, experience."(3) + </p> + <p> + To Cuvier's argument from the fixity of Egyptian mummified birds and + animals, as above stated, Lamarck replied that this proved nothing except + that the ibis had become perfectly adapted to its Egyptian surroundings in + an early day, historically speaking, and that the climatic and other + conditions of the Nile Valley had not since then changed. His theory, he + alleged, provided for the stability of species under fixed conditions + quite as well as for transmutation under varying conditions. + </p> + <p> + But, needless to say, the popular verdict lay with Cuvier; talent won for + the time against genius, and Lamarck was looked upon as an impious + visionary. His faith never wavered, however. He believed that he had + gained a true insight into the processes of animate nature, and he + reiterated his hypotheses over and over, particularly in the introduction + to his Histoire Naturelle des Animaux sans Vertebres, in 1815, and in his + Systeme des Connaissances Positives de l'Homme, in 1820. He lived on till + 1829, respected as a naturalist, but almost unrecognized as a prophet. + </p> + <p> + TENTATIVE ADVANCES + </p> + <p> + While the names of Darwin and Goethe, and in particular that of Lamarck, + must always stand out in high relief in this generation as the exponents + of the idea of transmutation of species, there are a few others which must + not be altogether overlooked in this connection. Of these the most + conspicuous is that of Gottfried Reinhold Treviranus, a German naturalist + physician, professor of mathematics in the lyceum at Bremen. + </p> + <p> + It was an interesting coincidence that Treviranus should have published + the first volume of his Biologie, oder Philosophie der lebenden Natur, in + which his views on the transmutation of species were expounded, in 1802, + the same twelvemonth in which Lamarck's first exposition of the same + doctrine appeared in his Recherches sur l'Organisation des Corps Vivants. + It is singular, too, that Lamarck, in his Hydrogelogie of the same date, + should independently have suggested "biology" as an appropriate word to + express the general science of living things. It is significant of the + tendency of thought of the time that the need of such a unifying word + should have presented itself simultaneously to independent thinkers in + different countries. + </p> + <p> + That same memorable year, Lorenz Oken, another philosophical naturalist, + professor in the University of Zurich, published the preliminary outlines + of his Philosophie der Natur, which, as developed through later + publications, outlined a theory of spontaneous generation and of evolution + of species. Thus it appears that this idea was germinating in the minds of + several of the ablest men of the time during the first decade of our + century. But the singular result of their various explications was to give + sudden check to that undercurrent of thought which for some time had been + setting towards this conception. As soon as it was made clear whither the + concession that animals may be changed by their environment must logically + trend, the recoil from the idea was instantaneous and fervid. Then for a + generation Cuvier was almost absolutely dominant, and his verdict was + generally considered final. + </p> + <p> + There was, indeed, one naturalist of authority in France who had the + hardihood to stand out against Cuvier and his school, and who was in a + position to gain a hearing, though by no means to divide the following. + This was Etienne Geoffroy Saint-Hilaire, the famous author of the + Philosophie Anatomique, and for many years the colleague of Lamarck at the + Jardin des Plantes. Like Goethe, Geoffroy was pre-eminently an anatomist, + and, like the great German, he had early been impressed with the + resemblances between the analogous organs of different classes of beings. + He conceived the idea that an absolute unity of type prevails throughout + organic nature as regards each set of organs. Out of this idea grew his + gradually formed belief that similarity of structure might imply identity + of origin—that, in short, one species of animal might have developed + from another. + </p> + <p> + Geoffroy's grasp of this idea of transmutation was by no means so complete + as that of Lamarck, and he seems never to have fully determined in his own + mind just what might be the limits of such development of species. + Certainly he nowhere includes all organic creatures in one line of + descent, as Lamarck had done; nevertheless, he held tenaciously to the + truth as he saw it, in open opposition to Cuvier, with whom he held a + memorable debate at the Academy of Sciences in 1830—the debate which + so aroused the interest and enthusiasm of Goethe, but which, in the + opinion of nearly every one else, resulted in crushing defeat for + Geoffrey, and brilliant, seemingly final, victory for the advocate of + special creation and the fixity of species. + </p> + <p> + With that all ardent controversy over the subject seemed to end, and for + just a quarter of a century to come there was published but a single + argument for transmutation of species which attracted any general + attention whatever. This oasis in a desert generation was a little book + called Vestiges of the Natural History of Creation, which appeared + anonymously in England in 1844, and which passed through numerous + editions, and was the subject of no end of abusive and derisive comment. + This book, the authorship of which remained for forty years a secret, is + now conceded to have been the work of Robert Chambers, the well-known + English author and publisher. The book itself is remarkable as being an + avowed and unequivocal exposition of a general doctrine of evolution, its + view being as radical and comprehensive as that of Lamarck himself. But it + was a resume of earlier efforts rather than a new departure, to say + nothing of its technical shortcomings, which may best be illustrated by a + quotation. + </p> + <p> + "The whole question," says Chambers, "stands thus: For the theory of + universal order—that is, order as presiding in both the origin and + administration of the world—we have the testimony of a vast number + of facts in nature, and this one in addition—that whatever is left + from the domain of ignorance, and made undoubted matter of science, forms + a new support to the same doctrine. The opposite view, once predominant, + has been shrinking for ages into lesser space, and now maintains a footing + only in a few departments of nature which happen to be less liable than + others to a clear investigation. The chief of these, if not almost the + only one, is the origin of the organic kingdoms. So long as this remains + obscure, the supernatural will have a certain hold upon enlightened + persons. Should it ever be cleared up in a way that leaves no doubt of a + natural origin of plants and animals, there must be a complete revolution + in the view which is generally taken of the relation of the Father of our + being. + </p> + <p> + "This prepares the way for a few remarks on the present state of opinion + with regard to the origin of organic nature. The great difficulty here is + the apparent determinateness of species. These forms of life being + apparently unchangeable, or at least always showing a tendency to return + to the character from which they have diverged, the idea arises that there + can have been no progression from one to another; each must have taken its + special form, independently of other forms, directly from the appointment + of the Creator. The Edinburgh Review writer says, 'they were created by + the hand of God and adapted to the conditions of the period.' Now it is, + in the first place, not certain that species constantly maintain a fixed + character, for we have seen that what were long considered as determinate + species have been transmuted into others. Passing, however, from this + fact, as it is not generally received among men of science, there remain + some great difficulties in connection with the idea of special creation. + First we should have to suppose, as pointed out in my former volume, a + most startling diversity of plan in the divine workings, a great general + plan or system of law in the leading events of world-making, and a plan of + minute, nice operation, and special attention in some of the mere details + of the process. The discrepancy between the two conceptions is surely + overpowering, when we allow ourselves to see the whole matter in a steady + and rational light. There is, also, the striking fact of an ascertained + historical progress of plants and animals in the order of their + organization; marine and cellular plants and invertebrated animals first, + afterwards higher examples of both. In an arbitrary system we had surely + no reason to expect mammals after reptiles; yet in this order they came. + The writer in the Edinburgh Review speaks of animals as coming in + adaptation to conditions, but this is only true in a limited sense. The + groves which formed the coal-beds might have been a fitting habitation for + reptiles, birds, and mammals, as such groves are at the present day; yet + we see none of the last of these classes and hardly any traces of the two + first at that period of the earth. Where the iguanodon lived the elephant + might have lived, but there was no elephant at that time. The sea of the + Lower Silurian era was capable of supporting fish, but no fish existed. It + hence forcibly appears that theatres of life must have remained + unserviceable, or in the possession of a tenantry inferior to what might + have enjoyed them, for many ages: there surely would have been no such + waste allowed in a system where Omnipotence was working upon the plan of + minute attention to specialities. The fact seems to denote that the actual + procedure of the peopling of the earth was one of a natural kind, + requiring a long space of time for its evolution. In this supposition the + long existence of land without land animals, and more particularly without + the noblest classes and orders, is only analogous to the fact, not nearly + enough present to the minds of a civilized people, that to this day the + bulk of the earth is a waste as far as man is concerned. + </p> + <p> + "Another startling objection is in the infinite local variation of organic + forms. Did the vegetable and animal kingdoms consist of a definite number + of species adapted to peculiarities of soil and climate, and universally + distributed, the fact would be in harmony with the idea of special + exertion. But the truth is that various regions exhibit variations + altogether without apparent end or purpose. Professor Henslow enumerates + forty-five distinct flowers or sets of plants upon the surface of the + earth, notwithstanding that many of these would be equally suitable + elsewhere. The animals of different continents are equally various, few + species being the same in any two, though the general character may + conform. The inference at present drawn from this fact is that there must + have been, to use the language of the Rev. Dr. Pye Smith, 'separate and + original creations, perhaps at different and respectively distinct + epochs.' It seems hardly conceivable that rational men should give an + adherence to such a doctrine when we think of what it involves. In the + single fact that it necessitates a special fiat of the inconceivable + Author of this sand-cloud of worlds to produce the flora of St. Helena, we + read its more than sufficient condemnation. It surely harmonizes far + better with our general ideas of nature to suppose that, just as all else + in this far-spread science was formed on the laws impressed upon it at + first by its Author, so also was this. An exception presented to us in + such a light appears admissible only when we succeed in forbidding our + minds to follow out those reasoning processes to which, by another law of + the Almighty, they tend, and for which they are adapted."(4) + </p> + <p> + Such reasoning as this naturally aroused bitter animadversions, and cannot + have been without effect in creating an undercurrent of thought in + opposition to the main trend of opinion of the time. But the book can + hardly be said to have done more than that. Indeed, some critics have + denied it even this merit. After its publication, as before, the + conception of transmutation of species remained in the popular estimation, + both lay and scientific, an almost forgotten "heresy." + </p> + <p> + It is true that here and there a scientist of greater or less repute—as + Von Buch, Meckel, and Von Baer in Germany, Bory Saint-Vincent in France, + Wells, Grant, and Matthew in England, and Leidy in America—had + expressed more or less tentative dissent from the doctrine of special + creation and immutability of species, but their unaggressive suggestions, + usually put forward in obscure publications, and incidentally, were + utterly overlooked and ignored. And so, despite the scientific advances + along many lines at the middle of the century, the idea of the + transmutability of organic races had no such prominence, either in + scientific or unscientific circles, as it had acquired fifty years before. + Special creation held the day, seemingly unopposed. + </p> + <p> + DARWIN AND THE ORIGIN OF SPECIES + </p> + <p> + But even at this time the fancied security of the special-creation + hypothesis was by no means real. Though it seemed so invincible, its real + position was that of an apparently impregnable fortress beneath which, all + unbeknown to the garrison, a powder-mine has been dug and lies ready for + explosion. For already there existed in the secluded work-room of an + English naturalist, a manuscript volume and a portfolio of notes which + might have sufficed, if given publicity, to shatter the entire structure + of the special-creation hypothesis. The naturalist who, by dint of long + and patient effort, had constructed this powder-mine of facts was Charles + Robert Darwin, grandson of the author of Zoonomia. + </p> + <p> + As long ago as July 1, 1837, young Darwin, then twenty-eight years of age, + had opened a private journal, in which he purposed to record all facts + that came to him which seemed to have any bearing on the moot point of the + doctrine of transmutation of species. Four or five years earlier, during + the course of that famous trip around the world with Admiral Fitzroy, as + naturalist to the Beagle, Darwin had made the personal observations which + first tended to shake his belief of the fixity of species. In South + America, in the Pampean formation, he had discovered "great fossil animals + covered with armor like that on the existing armadillos," and had been + struck with this similarity of type between ancient and existing faunas of + the same region. He was also greatly impressed by the manner in which + closely related species of animals were observed to replace one another as + he proceeded southward over the continent; and "by the South-American + character of most of the productions of the Galapagos Archipelago, and + more especially by the manner in which they differ slightly on each island + of the group, none of the islands appearing to be very ancient in a + geological sense." + </p> + <p> + At first the full force of these observations did not strike him; for, + under sway of Lyell's geological conceptions, he tentatively explained the + relative absence of life on one of the Galapagos Islands by suggesting + that perhaps no species had been created since that island arose. But + gradually it dawned upon him that such facts as he had observed "could + only be explained on the supposition that species gradually become + modified." From then on, as he afterwards asserted, the subject haunted + him; hence the journal of 1837. + </p> + <p> + It will thus be seen that the idea of the variability of species came to + Charles Darwin as an inference from personal observations in the field, + not as a thought borrowed from books. He had, of course, read the works of + his grandfather much earlier in life, but the arguments of Zoonomia and + The Temple of Nature had not served in the least to weaken his acceptance + of the current belief in fixity of species. Nor had he been more impressed + with the doctrine of Lamarck, so closely similar to that of his + grandfather. Indeed, even after his South-American experience had aroused + him to a new point of view he was still unable to see anything of value in + these earlier attempts at an explanation of the variation of species. In + opening his journal, therefore, he had no preconceived notion of upholding + the views of these or any other makers of hypotheses, nor at the time had + he formulated any hypothesis of his own. His mind was open and receptive; + he was eager only for facts which might lead him to an understanding of a + problem which seemed utterly obscure. It was something to feel sure that + species have varied; but how have such variations been brought about? + </p> + <p> + It was not long before Darwin found a clew which he thought might lead to + the answer he sought. In casting about for facts he had soon discovered + that the most available field for observation lay among domesticated + animals, whose numerous variations within specific lines are familiar to + every one. Thus under domestication creatures so tangibly different as a + mastiff and a terrier have sprung from a common stock. So have the + Shetland pony, the thoroughbred, and the draught-horse. In short, there is + no domesticated animal that has not developed varieties deviating more or + less widely from the parent stock. Now, how has this been accomplished? + Why, clearly, by the preservation, through selective breeding, of + seemingly accidental variations. Thus one horseman, by constantly + selecting animals that "chance" to have the right build and stamina, + finally develops a race of running-horses; while another horseman, by + selecting a different series of progenitors, has developed a race of slow, + heavy draught animals. + </p> + <p> + So far, so good; the preservation of "accidental" variations through + selective breeding is plainly a means by which races may be developed that + are very different from their original parent form. But this is under + man's supervision and direction. By what process could such selection be + brought about among creatures in a state of nature? Here surely was a + puzzle, and one that must be solved before another step could be taken in + this direction. + </p> + <p> + The key to the solution of this puzzle came into Darwin's mind through a + chance reading of the famous essay on "Population" which Thomas Robert + Malthus had published almost half a century before. This essay, expositing + ideas by no means exclusively original with Malthus, emphasizes the fact + that organisms tend to increase at a geometrical ratio through successive + generations, and hence would overpopulate the earth if not somehow kept in + check. Cogitating this thought, Darwin gained a new insight into the + processes of nature. He saw that in virtue of this tendency of each race + of beings to overpopulate the earth, the entire organic world, animal and + vegetable, must be in a state of perpetual carnage and strife, individual + against individual, fighting for sustenance and life. + </p> + <p> + That idea fully imagined, it becomes plain that a selective influence is + all the time at work in nature, since only a few individuals, relatively, + of each generation can come to maturity, and these few must, naturally, be + those best fitted to battle with the particular circumstances in the midst + of which they are placed. In other words, the individuals best adapted to + their surroundings will, on the average, be those that grow to maturity + and produce offspring. To these offspring will be transmitted the + favorable peculiarities. Thus these peculiarities will become permanent, + and nature will have accomplished precisely what the human breeder is seen + to accomplish. Grant that organisms in a state of nature vary, however + slightly, one from another (which is indubitable), and that such + variations will be transmitted by a parent to its offspring (which no one + then doubted); grant, further, that there is incessant strife among the + various organisms, so that only a small proportion can come to maturity—grant + these things, said Darwin, and we have an explanation of the preservation + of variations which leads on to the transmutation of species themselves. + </p> + <p> + This wonderful coign of vantage Darwin had reached by 1839. Here was the + full outline of his theory; here were the ideas which afterwards came to + be embalmed in familiar speech in the phrases "spontaneous variation," and + the "survival of the fittest," through "natural selection." After such a + discovery any ordinary man would at once have run through the streets of + science, so to speak, screaming "Eureka!" Not so Darwin. He placed the + manuscript outline of his theory in his portfolio, and went on gathering + facts bearing on his discovery. In 1844 he made an abstract in a + manuscript book of the mass of facts by that time accumulated. He showed + it to his friend Hooker, made careful provision for its publication in the + event of his sudden death, then stored it away in his desk and went ahead + with the gathering of more data. This was the unexploded powder-mine to + which I have just referred. + </p> + <p> + Twelve years more elapsed—years during which the silent worker + gathered a prodigious mass of facts, answered a multitude of objections + that arose in his own mind, vastly fortified his theory. All this time the + toiler was an invalid, never knowing a day free from illness and + discomfort, obliged to husband his strength, never able to work more than + an hour and a half at a stretch; yet he accomplished what would have been + vast achievements for half a dozen men of robust health. Two friends among + the eminent scientists of the day knew of his labors—Sir Joseph + Hooker, the botanist, and Sir Charles Lyell, the geologist. Gradually + Hooker had come to be more than half a convert to Darwin's views. Lyell + was still sceptical, yet he urged Darwin to publish his theory without + further delay lest he be forestalled. At last the patient worker decided + to comply with this advice, and in 1856 he set to work to make another and + fuller abstract of the mass of data he had gathered. + </p> + <p> + And then a strange thing happened. After Darwin had been at work on his + "abstract" about two years, but before he had published a line of it, + there came to him one day a paper in manuscript, sent for his approval by + a naturalist friend named Alfred Russel Wallace, who had been for some + time at work in the East India Archipelago. He read the paper, and, to his + amazement, found that it contained an outline of the same theory of + "natural selection" which he himself had originated and for twenty years + had worked upon. Working independently, on opposite sides of the globe, + Darwin and Wallace had hit upon the same explanation of the cause of + transmutation of species. "Were Wallace's paper an abstract of my + unpublished manuscript of 1844," said Darwin, "it could not better express + my ideas." + </p> + <p> + Here was a dilemma. To publish this paper with no word from Darwin would + give Wallace priority, and wrest from Darwin the credit of a discovery + which he had made years before his codiscoverer entered the field. Yet, on + the other hand, could Darwin honorably do otherwise than publish his + friend's paper and himself remain silent? It was a complication well + calculated to try a man's soul. Darwin's was equal to the test. Keenly + alive to the delicacy of the position, he placed the whole matter before + his friends Hooker and Lyell, and left the decision as to a course of + action absolutely to them. Needless to say, these great men did the one + thing which insured full justice to all concerned. They counselled a joint + publication, to include on the one hand Wallace's paper, and on the other + an abstract of Darwin's ideas, in the exact form in which it had been + outlined by the author in a letter to Asa Gray in the previous year—an + abstract which was in Gray's hands before Wallace's paper was in + existence. This joint production, together with a full statement of the + facts of the case, was presented to the Linnaean Society of London by + Hooker and Lyell on the evening of July 1, 1858, this being, by an odd + coincidence, the twenty-first anniversary of the day on which Darwin had + opened his journal to collect facts bearing on the "species question." Not + often before in the history of science has it happened that a great theory + has been nurtured in its author's brain through infancy and adolescence to + its full legal majority before being sent out into the world. + </p> + <p> + Thus the fuse that led to the great powder-mine had been lighted. The + explosion itself came more than a year later, in November, 1859, when + Darwin, after thirteen months of further effort, completed the outline of + his theory, which was at first begun as an abstract for the Linnaean + Society, but which grew to the size of an independent volume despite his + efforts at condensation, and which was given that ever-to-be-famous title, + The Origin of Species by Means of Natural Selection, or the Preservation + of Favored Races in the Struggle for Life. And what an explosion it was! + The joint paper of 1858 had made a momentary flare, causing the hearers, + as Hooker said, to "speak of it with bated breath," but beyond that it + made no sensation. What the result was when the Origin itself appeared no + one of our generation need be told. The rumble and roar that it made in + the intellectual world have not yet altogether ceased to echo after more + than forty years of reverberation. + </p> + <p> + NEW CHAMPIONS + </p> + <p> + To the Origin of Species, then, and to its author, Charles Darwin, must + always be ascribed chief credit for that vast revolution in the + fundamental beliefs of our race which has come about since 1859, and which + made the second half of the century memorable. But it must not be + overlooked that no such sudden metamorphosis could have been effected had + it not been for the aid of a few notable lieutenants, who rallied to the + standards of the leader immediately after the publication of the Origin. + Darwin had all along felt the utmost confidence in the ultimate triumph of + his ideas. "Our posterity," he declared, in a letter to Hooker, "will + marvel as much about the current belief (in special creation) as we do + about fossil shells having been thought to be created as we now see them." + But he fully realized that for the present success of his theory of + transmutation the championship of a few leaders of science was + all-essential. He felt that if he could make converts of Hooker and Lyell + and of Thomas Henry Huxley at once, all would be well. + </p> + <p> + His success in this regard, as in others, exceeded his expectations. + Hooker was an ardent disciple from reading the proof-sheets before the + book was published; Lyell renounced his former beliefs and fell into line + a few months later; while Huxley, so soon as he had mastered the central + idea of natural selection, marvelled that so simple yet all-potent a + thought had escaped him so long, and then rushed eagerly into the fray, + wielding the keenest dialectic blade that was drawn during the entire + controversy. Then, too, unexpected recruits were found in Sir John Lubbock + and John Tyndall, who carried the war eagerly into their respective + territories; while Herbert Spencer, who had advocated a doctrine of + transmutation on philosophic grounds some years before Darwin published + the key to the mystery—and who himself had barely escaped + independent discovery of that key—lent his masterful influence to + the cause. In America the famous botanist Asa Gray, who had long been a + correspondent of Darwin's but whose advocacy of the new theory had not + been anticipated, became an ardent propagandist; while in Germany Ernst + Heinrich Haeckel, the youthful but already noted zoologist, took up the + fight with equal enthusiasm. + </p> + <p> + Against these few doughty champions—with here and there another of + less general renown—was arrayed, at the outset, practically all + Christendom. The interest of the question came home to every person of + intelligence, whatever his calling, and the more deeply as it became more + and more clear how far-reaching are the real bearings of the doctrine of + natural selection. Soon it was seen that should the doctrine of the + survival of the favored races through the struggle for existence win, + there must come with it as radical a change in man's estimate of his own + position as had come in the day when, through the efforts of Copernicus + and Galileo, the world was dethroned from its supposed central position in + the universe. The whole conservative majority of mankind recoiled from + this necessity with horror. And this conservative majority included not + laymen merely, but a vast preponderance of the leaders of science also. + </p> + <p> + With the open-minded minority, on the other hand, the theory of natural + selection made its way by leaps and bounds. Its delightful simplicity—which + at first sight made it seem neither new nor important—coupled with + the marvellous comprehensiveness of its implications, gave it a hold on + the imagination, and secured it a hearing where other theories of + transmutation of species had been utterly scorned. Men who had found + Lamarck's conception of change through voluntary effort ridiculous, and + the vaporings of the Vestiges altogether despicable, men whose scientific + cautions held them back from Spencer's deductive argument, took eager hold + of that tangible, ever-present principle of natural selection, and were + led on and on to its goal. Hour by hour the attitude of the thinking world + towards this new principle changed; never before was so great a revolution + wrought so suddenly. + </p> + <p> + Nor was this merely because "the times were ripe" or "men's minds prepared + for evolution." Darwin himself bears witness that this was not altogether + so. All through the years in which he brooded this theory he sounded his + scientific friends, and could find among them not one who acknowledged a + doctrine of transmutation. The reaction from the stand-point of Lamarck + and Erasmus Darwin and Goethe had been complete, and when Charles Darwin + avowed his own conviction he expected always to have it met with ridicule + or contempt. In 1857 there was but one man speaking with any large degree + of authority in the world who openly avowed a belief in transmutation of + species—that man being Herbert Spencer. But the Origin of Species + came, as Huxley has said, like a flash in the darkness, enabling the + benighted voyager to see the way. The score of years during which its + author had waited and worked had been years well spent. Darwin had become, + as he himself says, a veritable Croesus, "overwhelmed with his riches in + facts"—facts of zoology, of selective artificial breeding, of + geographical distribution of animals, of embryology, of paleontology. He + had massed his facts about his theory, condensed them and recondensed, + until his volume of five hundred pages was an encyclopaedia in scope. + During those long years of musing he had thought out almost every + conceivable objection to his theory, and in his book every such objection + was stated with fullest force and candor, together with such reply as the + facts at command might dictate. It was the force of those twenty years of + effort of a master-mind that made the sudden breach in the breaswtork{sic} + of current thought. + </p> + <p> + Once this breach was effected the work of conquest went rapidly on. Day by + day squads of the enemy capitulated and struck their arms. By the time + another score of years had passed the doctrine of evolution had become the + working hypothesis of the scientific world. The revolution had been + effected. + </p> + <p> + And from amid the wreckage of opinion and belief stands forth the figure + of Charles Darwin, calm, imperturbable, serene; scatheless to ridicule, + contumely, abuse; unspoiled by ultimate success; unsullied alike by the + strife and the victory—take him for all in all, for character, for + intellect, for what he was and what he did, perhaps the most Socratic + figure of the century. When, in 1882, he died, friend and foe alike + conceded that one of the greatest sons of men had rested from his labors, + and all the world felt it fitting that the remains of Charles Darwin + should be entombed in Westminster Abbey close beside the honored grave of + Isaac Newton. Nor were there many who would dispute the justice of + Huxley's estimate of his accomplishment: "He found a great truth trodden + under foot. Reviled by bigots, and ridiculed by all the world, he lived + long enough to see it, chiefly by his own efforts, irrefragably + established in science, inseparably incorporated with the common thoughts + of men, and only hated and feared by those who would revile but dare not." + </p> + <p> + THE ORIGIN OF THE FITTEST + </p> + <p> + Wide as are the implications of the great truth which Darwin and his + co-workers established, however, it leaves quite untouched the problem of + the origin of those "favored variations" upon which it operates. That such + variations are due to fixed and determinate causes no one understood + better than Darwin; but in his original exposition of his doctrine he made + no assumption as to what these causes are. He accepted the observed fact + of variation—as constantly witnessed, for example, in the + differences between parents and offspring—and went ahead from this + assumption. + </p> + <p> + But as soon as the validity of the principle of natural selection came to + be acknowledged speculators began to search for the explanation of those + variations which, for purposes of argument, had been provisionally called + "spontaneous." Herbert Spencer had all along dwelt on this phase of the + subject, expounding the Lamarckian conceptions of the direct influence of + the environment (an idea which had especially appealed to Buffon and to + Geoffroy Saint-Hilaire), and of effort in response to environment and + stimulus as modifying the individual organism, and thus supplying the + basis for the operation of natural selection. Haeckel also became an + advocate of this idea, and presently there arose a so-called school of + neo-Lamarckians, which developed particular strength and prominence in + America under the leadership of Professors A. Hyatt and E. D. Cope. + </p> + <p> + But just as the tide of opinion was turning strongly in this direction, an + utterly unexpected obstacle appeared in the form of the theory of + Professor August Weismann, put forward in 1883, which antagonized the + Lamarckian conception (though not touching the Darwinian, of which + Weismann is a firm upholder) by denying that individual variations, + however acquired by the mature organism, are transmissible. The flurry + which this denial created has not yet altogether subsided, but subsequent + observations seem to show that it was quite disproportionate to the real + merits of the case. Notwithstanding Professor Weismann's objections, the + balance of evidence appears to favor the view that the Lamarckian factor + of acquired variations stands as the complement of the Darwinian factor of + natural selection in effecting the transmutation of species. + </p> + <p> + Even though this partial explanation of what Professor Cope calls the + "origin of the fittest" be accepted, there still remains one great life + problem which the doctrine of evolution does not touch. The origin of + species, genera, orders, and classes of beings through endless + transmutations is in a sense explained; but what of the first term of this + long series? Whence came that primordial organism whose transmuted + descendants make up the existing faunas and floras of the globe? + </p> + <p> + There was a time, soon after the doctrine of evolution gained a hearing, + when the answer to that question seemed to some scientists of authority to + have been given by experiment. Recurring to a former belief, and repeating + some earlier experiments, the director of the Museum of Natural History at + Rouen, M. F. A. Pouchet, reached the conclusion that organic beings are + spontaneously generated about us constantly, in the familiar processes of + putrefaction, which were known to be due to the agency of microscopic + bacteria. But in 1862 Louis Pasteur proved that this seeming spontaneous + generation is in reality due to the existence of germs in the air. + Notwithstanding the conclusiveness of these experiments, the claims of + Pouchet were revived in England ten years later by Professor Bastian; but + then the experiments of John Tyndall, fully corroborating the results of + Pasteur, gave a final quietus to the claim of "spontaneous generation" as + hitherto formulated. + </p> + <p> + There for the moment the matter rests. But the end is not yet. Fauna and + flora are here, and, thanks to Lamarck and Wallace and Darwin, their + development, through the operation of those "secondary causes" which we + call laws of nature, has been proximally explained. The lowest forms of + life have been linked with the highest in unbroken chains of descent. + Meantime, through the efforts of chemists and biologists, the gap between + the inorganic and the organic worlds, which once seemed almost infinite, + has been constantly narrowed. Already philosophy can throw a bridge across + that gap. But inductive science, which builds its own bridges, has not yet + spanned the chasm, small though it appear. Until it shall have done so, + the bridge of organic evolution is not quite complete; yet even as it + stands to-day it is perhaps the most stupendous scientific structure of + the nineteenth century. + </p> + <p> + <a name="link2H_4_0008" id="link2H_4_0008"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VII. EIGHTEENTH-CENTURY MEDICINE + </h2> + <h3> + THE SYSTEM OF BOERHAAVE + </h3> + <p> + At least two pupils of William Harvey distinguished themselves in + medicine, Giorgio Baglivi (1669-1707), who has been called the "Italian + Sydenham," and Hermann Boerhaave (1668-1738). The work of Baglivi was + hardly begun before his early death removed one of the most promising of + the early eighteenth-century physicians. Like Boerhaave, he represents a + type of skilled, practical clinitian rather than the abstract scientist. + One of his contributions to medical literature is the first accurate + description of typhoid, or, as he calls it, mesenteric fever. + </p> + <p> + If for nothing else, Boerhaave must always be remembered as the teacher of + Von Haller, but in his own day he was the widest known and the most + popular teacher in the medical world. He was the idol of his pupils at + Leyden, who flocked to his lectures in such numbers that it became + necessary to "tear down the walls of Leyden to accommodate them." His fame + extended not only all over Europe but to Asia, North America, and even + into South America. A letter sent him from China was addressed to + "Boerhaave in Europe." His teachings represent the best medical knowledge + of his day, a high standard of morality, and a keen appreciation of the + value of observation; and it was through such teachings imparted to his + pupils and advanced by them, rather than to any new discoveries, that his + name is important in medical history. His arrangement and classification + of the different branches of medicine are interesting as representing the + attitude of the medical profession towards these various branches at that + time. + </p> + <p> + "In the first place we consider Life; then Health, afterwards Diseases; + and lastly their several Remedies. + </p> + <p> + "Health the first general branch of Physic in our Institutions is termed + Physiology, or the Animal Oeconomy; demonstrating the several Parts of the + human Body, with their Mechanism and Actions. + </p> + <p> + "The second branch of Physic is called Pathology, treating of Diseases, + their Differences, Causes and Effects, or Symptoms; by which the human + Body is known to vary from its healthy state. + </p> + <p> + "The third part of Physic is termed Semiotica, which shows the Signs + distinguishing between sickness and Health, Diseases and their Causes in + the human Body; it also imports the State and Degrees of Health and + Diseases, and presages their future Events. + </p> + <p> + "The fourth general branch of Physic is termed Hygiene, or Prophylaxis. + </p> + <p> + "The fifth and last part of Physic is called Therapeutica; which instructs + us in the Nature, Preparation and uses of the Materia Medica; and the + methods of applying the same, in order to cure Diseases and restore lost + Health."(1) + </p> + <p> + From this we may gather that his general view of medicine was not unlike + that taken at the present time. + </p> + <p> + Boerhaave's doctrines were arranged into a "system" by Friedrich Hoffmann, + of Halle (1660-1742), this system having the merit of being simple and + more easily comprehended than many others. In this system forces were + considered inherent in matter, being expressed as mechanical movements, + and determined by mass, number, and weight. Similarly, forces express + themselves in the body by movement, contraction, and relaxation, etc., and + life itself is movement, "particularly movement of the heart." Life and + death are, therefore, mechanical phenomena, health is determined by + regularly recurring movements, and disease by irregularity of them. The + body is simply a large hydraulic machine, controlled by "the aether" or + "sensitive soul," and the chief centre of this soul lies in the medulla. + </p> + <p> + In the practical application of medicines to diseases Hoffman used simple + remedies, frequently with happy results, for whatever the medical man's + theory may be he seldom has the temerity to follow it out logically, and + use the remedies indicated by his theory to the exclusion of + long-established, although perhaps purely empirical, remedies. + Consequently, many vague theorists have been excellent practitioners, and + Hoffman was one of these. Some of the remedies he introduced are still in + use, notably the spirits of ether, or "Hoffman's anodyne." + </p> + <p> + ANIMISTS, VITALISTS, AND ORGANICISTS + </p> + <p> + Besides Hoffman's system of medicine, there were numerous others during + the eighteenth century, most of which are of no importance whatever; but + three, at least, that came into existence and disappeared during the + century are worthy of fuller notice. One of these, the Animists, had for + its chief exponent Georg Ernst Stahl of "phlogiston" fame; another, the + Vitalists, was championed by Paul Joseph Barthez (1734-1806); and the + third was the Organicists. This last, while agreeing with the other two + that vital activity cannot be explained by the laws of physics and + chemistry, differed in not believing that life "was due to some spiritual + entity," but rather to the structure of the body itself. + </p> + <p> + The Animists taught that the soul performed functions of ordinary life in + man, while the life of lower animals was controlled by ordinary mechanical + principles. Stahl supported this theory ardently, sometimes violently, at + times declaring that there were "no longer any doctors, only mechanics and + chemists." He denied that chemistry had anything to do with medicine, and, + in the main, discarded anatomy as useless to the medical man. The soul, he + thought, was the source of all vital movement; and the immediate cause of + death was not disease but the direct action of the soul. When through some + lesion, or because the machinery of the body has become unworkable, as in + old age, the soul leaves the body and death is produced. The soul + ordinarily selects the channels of the circulation, and the contractile + parts, as the route for influencing the body. Hence in fever the pulse is + quickened, due to the increased activity of the soul, and convulsions and + spasmodic movements in disease are due, to the, same cause. Stagnation of + the blood was supposed to be a fertile cause of diseases, and such + diseases were supposed to arise mostly from "plethora"—an + all-important element in Stahl's therapeutics. By many this theory is + regarded as an attempt on the part of the pious Stahl to reconcile + medicine and theology in a way satisfactory to both physicians and + theologians, but, like many conciliatory attempts, it was violently + opposed by both doctors and ministers. + </p> + <p> + A belief in such a theory would lead naturally to simplicity in + therapeutics, and in this respect at least Stahl was consistent. Since the + soul knew more about the body than any physician could know, Stahl + conceived that it would be a hinderance rather than a help for the + physician to interfere with complicated doses of medicine. As he advanced + in age this view of the administration of drugs grew upon him, until after + rejecting quinine, and finally opium, he at last used only salt and water + in treating his patients. From this last we may judge that his "system," + if not doing much good, was at least doing little harm. + </p> + <p> + The theory of the Vitalists was closely allied to that of the Animists, + and its most important representative, Paul Joseph Barthez, was a cultured + and eager scientist. After an eventful and varied career as physician, + soldier, editor, lawyer, and philosopher in turn, he finally returned to + the field of medicine, was made consulting physician by Napoleon in 1802, + and died in Paris four years later. + </p> + <p> + The theory that he championed was based on the assumption that there was a + "vital principle," the nature of which was unknown, but which differed + from the thinking mind, and was the cause of the phenomena of life. This + "vital principle" differed from the soul, and was not exhibited in human + beings alone, but even in animals and plants. This force, or whatever it + might be called, was supposed to be present everywhere in the body, and + all diseases were the results of it. + </p> + <p> + The theory of the Organicists, like that of the Animists and Vitalists, + agreed with the other two that vital activity could not be explained by + the laws of physics and chemistry, but, unlike them, it held that it was a + part of the structure of the body itself. Naturally the practical + physicians were more attracted by this tangible doctrine than by vague + theories "which converted diseases into unknown derangements of some + equally unknown 'principle.'" + </p> + <p> + It is perhaps straining a point to include this brief description of these + three schools of medicine in the history of the progress of the science. + But, on the whole, they were negatively at least prominent factors in + directing true progress along its proper channel, showing what courses + were not to be pursued. Some one has said that science usually stumbles + into the right course only after stumbling into all the wrong ones; and if + this be only partially true, the wrong ones still play a prominent if not + a very creditable part. Thus the medical systems of William Cullen + (1710-1790), and John Brown (1735-1788), while doing little towards the + actual advancement of scientific medicine, played so conspicuous a part in + so wide a field that the "Brunonian system" at least must be given some + little attention. + </p> + <p> + According to Brown's theory, life, diseases, and methods of cure are + explained by the property of "excitability." All exciting powers were + supposed to be stimulating, the apparent debilitating effects of some + being due to a deficiency in the amount of stimulus. Thus "the whole + phenomena of life, health, as well as disease, were supposed to consist of + stimulus and nothing else." This theory created a great stir in the + medical world, and partisans and opponents sprang up everywhere. In Italy + it was enthusiastically supported; in England it was strongly opposed; + while in Scotland riots took place between the opposing factions. Just why + this system should have created any stir, either for or against it, is not + now apparent. + </p> + <p> + Like so many of the other "theorists" of his century, Brown's practical + conclusions deduced from his theory (or perhaps in spite of it) were + generally beneficial to medicine, and some of them extremely valuable in + the treatment of diseases. He first advocated the modern stimulant, or + "feeding treatment" of fevers, and first recognized the usefulness of + animal soups and beef-tea in certain diseases. + </p> + <p> + THE SYSTEM OF HAHNEMANN + </p> + <p> + Just at the close of the century there came into prominence the school of + homoeopathy, which was destined to influence the practice of medicine very + materially and to outlive all the other eighteenth-century schools. It was + founded by Christian Samuel Friedrich Hahnemann (1755-1843), a most + remarkable man, who, after propounding a theory in his younger days which + was at least as reasonable as most of the existing theories, had the + misfortune to outlive his usefulness and lay his doctrine open to ridicule + by the unreasonable teachings of his dotage. + </p> + <p> + Hahnemann rejected all the teachings of morbid anatomy and pathology as + useless in practice, and propounded his famous "similia similibus + curantur"—that all diseases were to be cured by medicine which in + health produced symptoms dynamically similar to the disease under + treatment. If a certain medicine produced a headache when given to a + healthy person, then this medicine was indicated in case of headaches, + etc. At the present time such a theory seems crude enough, but in the + latter part of the eighteenth century almost any theory was as good as the + ones propounded by Animists, Vitalists, and other such schools. It + certainly had the very commendable feature of introducing simplicity in + the use of drugs in place of the complicated prescriptions then in vogue. + Had Hahnemann stopped at this point he could not have been held up to the + indefensible ridicule that was brought upon him, with considerable + justice, by his later theories. But he lived onto propound his + extraordinary theory of "potentiality"—that medicines gained + strength by being diluted—and his even more extraordinary theory + that all chronic diseases are caused either by the itch, syphilis, or + fig-wart disease, or are brought on by medicines. + </p> + <p> + At the time that his theory of potentialities was promulgated, the medical + world had gone mad in its administration of huge doses of compound + mixtures of drugs, and any reaction against this was surely an + improvement. In short, no medicine at all was much better than the heaping + doses used in common practice; and hence one advantage, at least, of + Hahnemann's methods. Stated briefly, his theory was that if a tincture be + reduced to one-fiftieth in strength, and this again reduced to + one-fiftieth, and this process repeated up to thirty such dilutions, the + potency of such a medicine will be increased by each dilution, Hahnemann + himself preferring the weakest, or, as he would call it, the strongest + dilution. The absurdity of such a theory is apparent when it is understood + that long before any drug has been raised to its thirtieth dilution it has + been so reduced in quantity that it cannot be weighed, measured, or + recognized as being present in the solution at all by any means known to + chemists. It is but just to modern followers of homoeopathy to say that + while most of them advocate small dosage, they do not necessarily follow + the teachings of Hahnemann in this respect, believing that the theory of + the dose "has nothing more to do with the original law of cure than the + psora (itch) theory has; and that it was one of the later creations of + Hahnemann's mind." + </p> + <p> + Hahnemann's theory that all chronic diseases are derived from either itch, + syphilis, or fig-wart disease is no longer advocated by his followers, + because it is so easily disproved, particularly in the case of itch. + Hahnemann taught that fully three-quarters of all diseases were caused by + "itch struck in," and yet it had been demonstrated long before his day, + and can be demonstrated any time, that itch is simply a local skin disease + caused by a small parasite. + </p> + <p> + JENNER AND VACCINATION + </p> + <p> + All advances in science have a bearing, near or remote, on the welfare of + our race; but it remains to credit to the closing decade of the eighteenth + century a discovery which, in its power of direct and immediate benefit to + humanity, surpasses any other discovery of this or any previous epoch. + Needless to say, I refer to Jenner's discovery of the method of preventing + smallpox by inoculation with the virus of cow-pox. It detracts nothing + from the merit of this discovery to say that the preventive power of + accidental inoculation had long been rumored among the peasantry of + England. Such vague, unavailing half-knowledge is often the forerunner of + fruitful discovery. + </p> + <p> + To all intents and purposes Jenner's discovery was original and unique. + Nor, considered as a perfect method, was it in any sense an accident. It + was a triumph of experimental science. The discoverer was no novice in + scientific investigation, but a trained observer, who had served a long + apprenticeship in scientific observation under no less a scientist than + the celebrated John Hunter. At the age of twenty-one Jenner had gone to + London to pursue his medical studies, and soon after he proved himself so + worthy a pupil that for two years he remained a member of Hunter's + household as his favorite pupil. His taste for science and natural history + soon attracted the attention of Sir Joseph Banks, who intrusted him with + the preparation of the zoological specimens brought back by Captain Cook's + expedition in 1771. He performed this task so well that he was offered the + position of naturalist to the second expedition, but declined it, + preferring to take up the practice of his profession in his native town of + Berkeley. + </p> + <p> + His many accomplishments and genial personality soon made him a favorite + both as a physician and in society. He was a good singer, a fair violinist + and flute-player, and a very successful writer of prose and verse. But + with all his professional and social duties he still kept up his + scientific investigations, among other things making some careful + observations on the hibernation of hedgehogs at the instigation of Hunter, + the results of which were laid before the Royal Society. He also made + quite extensive investigations as to the geological formations and fossils + found in his neighborhood. + </p> + <p> + Even during his student days with Hunter he had been much interested in + the belief, current in the rural districts of Gloucestershire, of the + antagonism between cow-pox and small-pox, a person having suffered from + cow-pox being immuned to small-pox. At various times Jenner had mentioned + the subject to Hunter, and he was constantly making inquiries of his + fellow-practitioners as to their observations and opinions on the subject. + Hunter was too fully engrossed in other pursuits to give the matter much + serious attention, however, and Jenner's brothers of the profession gave + scant credence to the rumors, although such rumors were common enough. + </p> + <p> + At this time the practice of inoculation for preventing small-pox, or + rather averting the severer forms of the disease, was widely practised. It + was customary, when there was a mild case of the disease, to take some of + the virus from the patient and inoculate persons who had never had the + disease, producing a similar attack in them. Unfortunately there were many + objections to this practice. The inoculated patient frequently developed a + virulent form of the disease and died; or if he recovered, even after a + mild attack, he was likely to be "pitted" and disfigured. But, perhaps + worst of all, a patient so inoculated became the source of infection to + others, and it sometimes happened that disastrous epidemics were thus + brought about. The case was a most perplexing one, for the awful scourge + of small-pox hung perpetually over the head of every person who had not + already suffered and recovered from it. The practice of inoculation was + introduced into England by Lady Mary Wortley Montague (1690-1762), who had + seen it practised in the East, and who announced her intention of + "introducing it into England in spite of the doctors." + </p> + <p> + From the fact that certain persons, usually milkmaids, who had suffered + from cow-pox seemed to be immuned to small-pox, it would seem a very + simple process of deduction to discover that cow-pox inoculation was the + solution of the problem of preventing the disease. But there was another + form of disease which, while closely resembling cow-pox and quite + generally confounded with it, did not produce immunity. The confusion of + these two forms of the disease had constantly misled investigations as to + the possibility of either of them immunizing against smallpox, and the + confusion of these two diseases for a time led Jenner to question the + possibility of doing so. After careful investigations, however, he reached + the conclusion that there was a difference in the effects of the two + diseases, only one of which produced immunity from small-pox. + </p> + <p> + "There is a disease to which the horse, from his state of domestication, + is frequently subject," wrote Jenner, in his famous paper on vaccination. + "The farriers call it the grease. It is an inflammation and swelling in + the heel, accompanied at its commencement with small cracks or fissures, + from which issues a limpid fluid possessing properties of a very peculiar + kind. This fluid seems capable of generating a disease in the human body + (after it has undergone the modification I shall presently speak of) which + bears so strong a resemblance to small-pox that I think it highly probable + it may be the source of that disease. + </p> + <p> + "In this dairy country a great number of cows are kept, and the office of + milking is performed indiscriminately by men and maid servants. One of the + former having been appointed to apply dressings to the heels of a horse + affected with the malady I have mentioned, and not paying due attention to + cleanliness, incautiously bears his part in milking the cows with some + particles of the infectious matter adhering to his fingers. When this is + the case it frequently happens that a disease is communicated to the cows, + and from the cows to the dairy-maids, which spreads through the farm until + most of the cattle and domestics feel its unpleasant consequences. This + disease has obtained the name of Cow-Pox. It appears on the nipples of the + cows in the form of irregular pustules. At their first appearance they are + commonly of a palish blue, or rather of a color somewhat approaching to + livid, and are surrounded by an inflammation. These pustules, unless a + timely remedy be applied, frequently degenerate into phagedenic ulcers, + which prove extremely troublesome. The animals become indisposed, and the + secretion of milk is much lessened. Inflamed spots now begin to appear on + different parts of the hands of the domestics employed in milking, and + sometimes on the wrists, which run on to suppuration, first assuming the + appearance of the small vesications produced by a burn. Most commonly they + appear about the joints of the fingers and at their extremities; but + whatever parts are affected, if the situation will admit the superficial + suppurations put on a circular form with their edges more elevated than + their centre and of a color distinctly approaching to blue. Absorption + takes place, and tumors appear in each axilla. The system becomes + affected, the pulse is quickened; shiverings, succeeded by heat, general + lassitude, and pains about the loins and limbs, with vomiting, come on. + The head is painful, and the patient is now and then even affected with + delirium. These symptoms, varying in their degrees of violence, generally + continue from one day to three or four, leaving ulcerated sores about the + hands which, from the sensibility of the parts, are very troublesome and + commonly heal slowly, frequently becoming phagedenic, like those from + which they sprang. During the progress of the disease the lips, nostrils, + eyelids, and other parts of the body are sometimes affected with sores; + but these evidently arise from their being heedlessly rubbed or scratched + by the patient's infected fingers. No eruptions on the skin have followed + the decline of the feverish symptoms in any instance that has come under + my inspection, one only excepted, and in this case a very few appeared on + the arms: they were very minute, of a vivid red color, and soon died away + without advancing to maturation, so that I cannot determine whether they + had any connection with the preceding symptoms. + </p> + <p> + "Thus the disease makes its progress from the horse (as I conceive) to the + nipple of the cow, and from the cow to the human subject. + </p> + <p> + "Morbid matter of various kinds, when absorbed into the system, may + produce effects in some degree similar; but what renders the cow-pox virus + so extremely singular is that the person that has been thus affected is + forever after secure from the infection of small-pox, neither exposure to + the variolous effluvia nor the insertion of the matter into the skin + producing this distemper."(2) + </p> + <p> + In 1796 Jenner made his first inoculation with cowpox matter, and two + months later the same subject was inoculated with small-pox matter. But, + as Jenner had predicted, no attack of small-pox followed. Although fully + convinced by this experiment that the case was conclusively proven, he + continued his investigations, waiting two years before publishing his + discovery. Then, fortified by indisputable proofs, he gave it to the + world. The immediate effects of his announcement have probably never been + equalled in the history of scientific discovery, unless, perhaps, in the + single instance of the discovery of anaesthesia. In Geneva and Holland + clergymen advocated the practice of vaccination from their pulpits; in + some of the Latin countries religious processions were formed for + receiving vaccination; Jenner's birthday was celebrated as a feast in + Germany; and the first child vaccinated in Russia was named "Vaccinov" and + educated at public expense. In six years the discovery had penetrated to + the most remote corners of civilization; it had even reached some savage + nations. And in a few years small-pox had fallen from the position of the + most dreaded of all diseases to that of being practically the only disease + for which a sure and easy preventive was known. + </p> + <p> + Honors were showered upon Jenner from the Old and the New World, and even + Napoleon, the bitter hater of the English, was among the others who + honored his name. On one occasion Jenner applied to the Emperor for the + release of certain Englishmen detained in France. The petition was about + to be rejected when the name of the petitioner was mentioned. "Ah," said + Napoleon, "we can refuse nothing to that name!" + </p> + <p> + It is difficult for us of to-day clearly to conceive the greatness of + Jenner's triumph, for we can only vaguely realize what a ruthless and + ever-present scourge smallpox had been to all previous generations of men + since history began. Despite all efforts to check it by medication and by + direct inoculation, it swept now and then over the earth as an + all-devastating pestilence, and year by year it claimed one-tenth of all + the beings in Christendom by death as its average quota of victims. "From + small-pox and love but few remain free," ran the old saw. A pitted face + was almost as much a matter of course a hundred years ago as a smooth one + is to-day. + </p> + <p> + Little wonder, then, that the world gave eager acceptance to Jenner's + discovery. No urging was needed to induce the majority to give it trial; + passengers on a burning ship do not hold aloof from the life-boats. Rich + and poor, high and low, sought succor in vaccination and blessed the name + of their deliverer. Of all the great names that were before the world in + the closing days of the century, there was perhaps no other one at once so + widely known and so uniformly reverenced as that of the great English + physician Edward Jenner. Surely there was no other one that should be + recalled with greater gratitude by posterity. + </p> + <p> + <a name="link2H_4_0009" id="link2H_4_0009"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + VIII. NINETEENTH-CENTURY MEDICINE + </h2> + <h3> + PHYSICAL DIAGNOSIS + </h3> + <p> + Although Napoleon Bonaparte, First Consul, was not lacking in + self-appreciation, he probably did not realize that in selecting a + physician for his own needs he was markedly influencing the progress of + medical science as a whole. Yet so strangely are cause and effect adjusted + in human affairs that this simple act of the First Consul had that very + unexpected effect. For the man chosen was the envoy of a new method in + medical practice, and the fame which came to him through being physician + to the First Consul, and subsequently to the Emperor, enabled him to + promulgate the method in a way otherwise impracticable. Hence the indirect + but telling value to medical science of Napoleon's selection. + </p> + <p> + The physician in question was Jean Nicolas de Corvisart. His novel method + was nothing more startling than the now-familiar procedure of tapping the + chest of a patient to elicit sounds indicative of diseased tissues within. + Every one has seen this done commonly enough in our day, but at the + beginning of the century Corvisart, and perhaps some of his pupils, were + probably the only physicians in the world who resorted to this simple and + useful procedure. Hence Napoleon's surprise when, on calling in Corvisart, + after becoming somewhat dissatisfied with his other physicians Pinel and + Portal, his physical condition was interrogated in this strange manner. + With characteristic shrewdness Bonaparte saw the utility of the method, + and the physician who thus attempted to substitute scientific method for + guess-work in the diagnosis of disease at once found favor in his eyes and + was installed as his regular medical adviser. + </p> + <p> + For fifteen years before this Corvisart had practised percussion, as the + chest-tapping method is called, without succeeding in convincing the + profession of its value. The method itself, it should be added, had not + originated with Corvisart, nor did the French physician for a moment claim + it as his own. The true originator of the practice was the German + physician Avenbrugger, who published a book about it as early as 1761. + This book had even been translated into French, then the language of + international communication everywhere, by Roziere de la Chassagne, of + Montpellier, in 1770; but no one other than Corvisart appears to have paid + any attention to either original or translation. It was far otherwise, + however, when Corvisart translated Avenbrugger's work anew, with important + additions of his own, in 1808. + </p> + <p> + "I know very well how little reputation is allotted to translator and + commentators," writes Corvisart, "and I might easily have elevated myself + to the rank of an author if I had elaborated anew the doctrine of + Avenbrugger and published an independent work on percussion. In this way, + however, I should have sacrificed the name of Avenbrugger to my own + vanity, a thing which I am unwilling to do. It is he, and the beautiful + invention which of right belongs to him, that I desire to recall to + life."(1) + </p> + <p> + By this time a reaction had set in against the metaphysical methods in + medicine that had previously been so alluring; the scientific spirit of + the time was making itself felt in medical practice; and this, combined + with Corvisart's fame, brought the method of percussion into immediate and + well-deserved popularity. Thus was laid the foundation for the method of + so-called physical diagnosis, which is one of the corner-stones of modern + medicine. + </p> + <p> + The method of physical diagnosis as practised in our day was by no means + completed, however, with the work of Corvisart. Percussion alone tells + much less than half the story that may be elicited from the organs of the + chest by proper interrogation. The remainder of the story can only be + learned by applying the ear itself to the chest, directly or indirectly. + Simple as this seems, no one thought of practising it for some years after + Corvisart had shown the value of percussion. + </p> + <p> + Then, in 1815, another Paris physician, Rene Theophile Hyacinthe Laennec, + discovered, almost by accident, that the sound of the heart-beat could be + heard surprisingly through a cylinder of paper held to the ear and against + the patient's chest. Acting on the hint thus received, Laennec substituted + a hollow cylinder of wood for the paper, and found himself provided with + an instrument through which not merely heart sounds but murmurs of the + lungs in respiration could be heard with almost startling distinctness. + </p> + <p> + The possibility of associating the varying chest sounds with diseased + conditions of the organs within appealed to the fertile mind of Laennec as + opening new vistas in therapeutics, which he determined to enter to the + fullest extent practicable. His connection with the hospitals of Paris + gave him full opportunity in this direction, and his labors of the next + few years served not merely to establish the value of the new method as an + aid to diagnosis, but laid the foundation also for the science of morbid + anatomy. In 1819 Laennec published the results of his labors in a work + called Traite d'Auscultation Mediate,(2) a work which forms one of the + landmarks of scientific medicine. By mediate auscultation is meant, of + course, the interrogation of the chest with the aid of the little + instrument already referred to, an instrument which its originator thought + hardly worth naming until various barbarous appellations were applied to + it by others, after which Laennec decided to call it the stethoscope, a + name which it has ever since retained. + </p> + <p> + In subsequent years the form of the stethoscope, as usually employed, was + modified and its value augmented by a binauricular attachment, and in very + recent years a further improvement has been made through application of + the principle of the telephone; but the essentials of auscultation with + the stethoscope were established in much detail by Laennec, and the honor + must always be his of thus taking one of the longest single steps by which + practical medicine has in our century acquired the right to be considered + a rational science. Laennec's efforts cost him his life, for he died in + 1826 of a lung disease acquired in the course of his hospital practice; + but even before this his fame was universal, and the value of his method + had been recognized all over the world. Not long after, in 1828, yet + another French physician, Piorry, perfected the method of percussion by + introducing the custom of tapping, not the chest directly, but the finger + or a small metal or hard-rubber plate held against the chest-mediate + percussion, in short. This perfected the methods of physical diagnosis of + diseases of the chest in all essentials; and from that day till this + percussion and auscultation have held an unquestioned place in the regular + armamentarium of the physician. + </p> + <p> + Coupled with the new method of physical diagnosis in the effort to + substitute knowledge for guess-work came the studies of the experimental + physiologists—in particular, Marshall Hall in England and Francois + Magendie in France; and the joint efforts of these various workers led + presently to the abandonment of those severe and often irrational + depletive methods—blood-letting and the like—that had + previously dominated medical practice. To this end also the "statistical + method," introduced by Louis and his followers, largely contributed; and + by the close of the first third of our century the idea was gaining ground + that the province of therapeutics is to aid nature in combating disease, + and that this may often be accomplished better by simple means than by the + heroic measures hitherto thought necessary. In a word, scientific + empiricism was beginning to gain a hearing in medicine as against the + metaphysical preconceptions of the earlier generations. + </p> + <p> + PARASITIC DISEASES + </p> + <p> + I have just adverted to the fact that Napoleon Bonaparte, as First Consul + and as Emperor, was the victim of a malady which caused him to seek the + advice of the most distinguished physicians of Paris. It is a little + shocking to modern sensibilities to read that these physicians, except + Corvisart, diagnosed the distinguished patient's malady as "gale + repercutee"—that is to say, in idiomatic English, the itch "struck + in." It is hardly necessary to say that no physician of today would make + so inconsiderate a diagnosis in the case of a royal patient. If by any + chance a distinguished patient were afflicted with the itch, the sagacious + physician would carefully hide the fact behind circumlocutions and proceed + to eradicate the disease with all despatch. That the physicians of + Napoleon did otherwise is evidence that at the beginning of the century + the disease in question enjoyed a very different status. At that time + itch, instead of being a most plebeian malady, was, so to say, a court + disease. It enjoyed a circulation, in high circles and in low, that modern + therapeutics has quite denied it; and the physicians of the time gave it a + fictitious added importance by ascribing to its influence the existence of + almost any obscure malady that came under their observation. Long after + Napoleon's time gale continued to hold this proud distinction. For + example, the imaginative Dr. Hahnemann did not hesitate to affirm, as a + positive maxim, that three-fourths of all the ills that flesh is heir to + were in reality nothing but various forms of "gale repercutee." + </p> + <p> + All of which goes to show how easy it may be for a masked pretender to + impose on credulous humanity, for nothing is more clearly established in + modern knowledge than the fact that "gale repercutee" was simply a name to + hide a profound ignorance; no such disease exists or ever did exist. Gale + itself is a sufficiently tangible reality, to be sure, but it is a purely + local disease of the skin, due to a perfectly definite cause, and the dire + internal conditions formerly ascribed to it have really no causal + connection with it whatever. This definite cause, as every one nowadays + knows, is nothing more or less than a microscopic insect which has found + lodgment on the skin, and has burrowed and made itself at home there. Kill + that insect and the disease is no more; hence it has come to be an axiom + with the modern physician that the itch is one of the three or four + diseases that he positively is able to cure, and that very speedily. But + it was far otherwise with the physicians of the first third of our + century, because to them the cause of the disease was an absolute mystery. + </p> + <p> + It is true that here and there a physician had claimed to find an insect + lodged in the skin of a sufferer from itch, and two or three times the + claim had been made that this was the cause of the malady, but such views + were quite ignored by the general profession, and in 1833 it was stated in + an authoritative medical treatise that the "cause of gale is absolutely + unknown." But even at this time, as it curiously happened, there were + certain ignorant laymen who had attained to a bit of medical knowledge + that was withheld from the inner circles of the profession. As the + peasantry of England before Jenner had known of the curative value of + cow-pox over small-pox, so the peasant women of Poland had learned that + the annoying skin disease from which they suffered was caused by an almost + invisible insect, and, furthermore, had acquired the trick of dislodging + the pestiferous little creature with the point of a needle. From them a + youth of the country, F. Renucci by name, learned the open secret. He + conveyed it to Paris when he went there to study medicine, and in 1834 + demonstrated it to his master Alibert. This physician, at first sceptical, + soon was convinced, and gave out the discovery to the medical world with + an authority that led to early acceptance. + </p> + <p> + Now the importance of all this, in the present connection, is not at all + that it gave the clew to the method of cure of a single disease. What + makes the discovery epochal is the fact that it dropped a brand-new idea + into the medical ranks—an idea destined, in the long-run, to prove + itself a veritable bomb—the idea, namely, that a minute and quite + unsuspected animal parasite may be the cause of a well-known, widely + prevalent, and important human disease. Of course the full force of this + idea could only be appreciated in the light of later knowledge; but even + at the time of its coming it sufficed to give a great impetus to that new + medical knowledge, based on microscopical studies, which had but recently + been made accessible by the inventions of the lens-makers. The new + knowledge clarified one very turbid medical pool and pointed the way to + the clarification of many others. + </p> + <p> + Almost at the same time that the Polish medical student was demonstrating + the itch mite in Paris, it chanced, curiously enough, that another medical + student, this time an Englishman, made an analogous discovery of perhaps + even greater importance. Indeed, this English discovery in its initial + stages slightly antedated the other, for it was in 1833 that the student + in question, James Paget, interne in St. Bartholomew's Hospital, London, + while dissecting the muscular tissues of a human subject, found little + specks of extraneous matter, which, when taken to the professor of + comparative anatomy, Richard Owen, were ascertained, with the aid of the + microscope, to be the cocoon of a minute and hitherto unknown insect. Owen + named the insect Trichina spiralis. After the discovery was published it + transpired that similar specks had been observed by several earlier + investigators, but no one had previously suspected or, at any rate, + demonstrated their nature. Nor was the full story of the trichina made out + for a long time after Owen's discovery. It was not till 1847 that the + American anatomist Dr. Joseph Leidy found the cysts of trichina in the + tissues of pork; and another decade or so elapsed after that before German + workers, chief among whom were Leuckart, Virchow, and Zenker, proved that + the parasite gets into the human system through ingestion of infected + pork, and that it causes a definite set of symptoms of disease which + hitherto had been mistaken for rheumatism, typhoid fever, and other + maladies. Then the medical world was agog for a time over the subject of + trichinosis; government inspection of pork was established in some parts + of Germany; American pork was excluded altogether from France; and the + whole subject thus came prominently to public attention. But important as + the trichina parasite proved on its own account in the end, its greatest + importance, after all, was in the share it played in directing attention + at the time of its discovery in 1833 to the subject of microscopic + parasites in general. + </p> + <p> + The decade that followed that discovery was a time of great activity in + the study of microscopic organisms and microscopic tissues, and such men + as Ehrenberg and Henle and Bory Saint-Vincent and Kolliker and Rokitansky + and Remak and Dujardin were widening the bounds of knowledge of this new + subject with details that cannot be more than referred to here. But the + crowning achievement of the period in this direction was the discovery + made by the German, J. L. Schoenlein, in 1839, that a very common and most + distressing disease of the scalp, known as favus, is really due to the + presence and growth on the scalp of a vegetable organism of microscopic + size. Thus it was made clear that not merely animal but also vegetable + organisms of obscure, microscopic species have causal relations to the + diseases with which mankind is afflicted. This knowledge of the parasites + was another long step in the direction of scientific medical knowledge; + but the heights to which this knowledge led were not to be scaled, or even + recognized, until another generation of workers had entered the field. + </p> + <p> + PAINLESS SURGERY + </p> + <p> + Meantime, in quite another field of medicine, events were developing which + led presently to a revelation of greater immediate importance to humanity + than any other discovery that had come in the century, perhaps in any + field of science whatever. This was the discovery of the pain-dispelling + power of the vapor of sulphuric ether inhaled by a patient undergoing a + surgical operation. This discovery came solely out of America, and it + stands curiously isolated, since apparently no minds in any other country + were trending towards it even vaguely. Davy, in England, had indeed + originated the method of medication by inhalation, and earned out some + most interesting experiments fifty years earlier, and it was doubtless his + experiments with nitrous oxide gas that gave the clew to one of the + American investigators; but this was the sole contribution of preceding + generations to the subject, and since the beginning of the century, when + Davy turned his attention to other matters, no one had made the slightest + advance along the same line until an American dentist renewed the + investigation. + </p> + <p> + In view of the sequel, Davy's experiments merit full attention. Here is + his own account of them, as written in 1799: + </p> + <p> + "Immediately after a journey of one hundred and twenty-six miles, in which + I had no sleep the preceding night, being much exhausted, I respired seven + quarts of nitrous oxide gas for near three minutes. It produced the usual + pleasurable effects and slight muscular motion. I continued exhilarated + for some minutes afterwards, but in half an hour found myself neither more + nor less exhausted than before the experiment. I had a great propensity to + sleep. + </p> + <p> + "To ascertain with certainty whether the more extensive action of nitrous + oxide compatible with life was capable of producing debility, I resolved + to breathe the gas for such a time, and in such quantities, as to produce + excitement equal in duration and superior in intensity to that occasioned + by high intoxication from opium or alcohol. + </p> + <p> + "To habituate myself to the excitement, and to carry it on gradually, on + December 26th I was enclosed in an air-tight breathing-box, of the + capacity of about nine and one-half cubic feet, in the presence of Dr. + Kinglake. After I had taken a situation in which I could by means of a + curved thermometer inserted under the arm, and a stop-watch, ascertain the + alterations in my pulse and animal heat, twenty quarts of nitrous oxide + were thrown into the box. + </p> + <p> + "For three minutes I experienced no alteration in my sensations, though + immediately after the introduction of the nitrous oxide the smell and + taste of it were very evident. In four minutes I began to feel a slight + glow in the cheeks and a generally diffused warmth over the chest, though + the temperature of the box was not quite 50 degrees.... In twenty-five + minutes the animal heat was 100 degrees, pulse 124. In thirty minutes + twenty quarts more of gas were introduced. + </p> + <p> + "My sensations were now pleasant; I had a generally diffused warmth + without the slightest moisture of the skin, a sense of exhilaration + similar to that produced by a small dose of wine, and a disposition to + muscular motion and to merriment. + </p> + <p> + "In three-quarters of an hour the pulse was 104 and the animal heat not + 99.5 degrees, the temperature of the chamber 64 degrees. The pleasurable + feelings continued to increase, the pulse became fuller and slower, till + in about an hour it was 88, when the animal heat was 99 degrees. Twenty + quarts more of air were admitted. I had now a great disposition to laugh, + luminous points seemed frequently to pass before my eyes, my hearing was + certainly more acute, and I felt a pleasant lightness and power of + exertion in my muscles. In a short time the symptoms became stationary; + breathing was rather oppressed, and on account of the great desire for + action rest was painful. + </p> + <p> + "I now came out of the box, having been in precisely an hour and a + quarter. The moment after I began to respire twenty quarts of unmingled + nitrous oxide. A thrilling extending from the chest to the extremities was + almost immediately produced. I felt a sense of tangible extension highly + pleasurable in every limb; my visible impressions were dazzling and + apparently magnified, I heard distinctly every sound in the room, and was + perfectly aware of my situation. By degrees, as the pleasurable sensations + increased, I lost all connection with external things; trains of vivid + visible images rapidly passed through my mind and were connected with + words in such a manner as to produce perceptions perfectly novel. + </p> + <p> + "I existed in a world of newly connected and newly modified ideas. I + theorized; I imagined that I made discoveries. When I was awakened from + this semi-delirious trance by Dr. Kinglake, who took the bag from my + mouth, indignation and pride were the first feelings produced by the sight + of persons about me. My emotions were enthusiastic and sublime; and for a + minute I walked about the room perfectly regardless of what was said to + me. As I recovered my former state of mind, I felt an inclination to + communicate the discoveries I had made during the experiment. I endeavored + to recall the ideas—they were feeble and indistinct; one collection + of terms, however, presented itself, and, with most intense belief and + prophetic manner, I exclaimed to Dr. Kinglake, 'Nothing exists but + thoughts!—the universe is composed of impressions, ideas, pleasures, + and pains.' "(3) + </p> + <p> + From this account we see that Davy has anaesthetized himself to a point + where consciousness of surroundings was lost, but not past the stage of + exhilaration. Had Dr. Kinglake allowed the inhaling-bag to remain in + Davy's mouth for a few moments longer complete insensibility would have + followed. As it was, Davy appears to have realized that sensibility was + dulled, for he adds this illuminative suggestion: "As nitrous oxide in its + extensive operation appears capable of destroying physical pain, it may + probably be used with advantage during surgical operations in which no + great effusion of blood takes place."(4) + </p> + <p> + Unfortunately no one took advantage of this suggestion at the time, and + Davy himself became interested in other fields of science and never + returned to his physiological studies, thus barely missing one of the + greatest discoveries in the entire field of science. In the generation + that followed no one seems to have thought of putting Davy's suggestion to + the test, and the surgeons of Europe had acknowledged with one accord that + all hope of finding a means to render operations painless must be utterly + abandoned—that the surgeon's knife must ever remain a synonym for + slow and indescribable torture. By an odd coincidence it chanced that Sir + Benjamin Brodie, the acknowledged leader of English surgeons, had publicly + expressed this as his deliberate though regretted opinion at a time when + the quest which he considered futile had already led to the most brilliant + success in America, and while the announcement of the discovery, which + then had no transatlantic cable to convey it, was actually on its way to + the Old World. + </p> + <p> + The American dentist just referred to, who was, with one exception to be + noted presently, the first man in the world to conceive that the + administration of a definite drug might render a surgical operation + painless and to give the belief application was Dr. Horace Wells, of + Hartford, Connecticut. The drug with which he experimented was nitrous + oxide—the same that Davy had used; the operation that he rendered + painless was no more important than the extraction of a tooth—yet it + sufficed to mark a principle; the year of the experiment was 1844. + </p> + <p> + The experiments of Dr. Wells, however, though important, were not + sufficiently demonstrative to bring the matter prominently to the + attention of the medical world. The drug with which he experimented proved + not always reliable, and he himself seems ultimately to have given the + matter up, or at least to have relaxed his efforts. But meantime a friend, + to whom he had communicated his belief and expectations, took the matter + up, and with unremitting zeal carried forward experiments that were + destined to lead to more tangible results. This friend was another + dentist, Dr. W. T. G. Morton, of Boston, then a young man full of youthful + energy and enthusiasm. He seems to have felt that the drug with which + Wells had experimented was not the most practicable one for the purpose, + and so for several months he experimented with other allied drugs, until + finally he hit upon sulphuric ether, and with this was able to make + experiments upon animals, and then upon patients in the dental chair, that + seemed to him absolutely demonstrative. + </p> + <p> + Full of eager enthusiasm, and absolutely confident of his results, he at + once went to Dr. J. C. Warren, one of the foremost surgeons of Boston, and + asked permission to test his discovery decisively on one of the patients + at the Boston Hospital during a severe operation. The request was granted; + the test was made on October 16, 1846, in the presence of several of the + foremost surgeons of the city and of a body of medical students. The + patient slept quietly while the surgeon's knife was plied, and awoke to + astonished comprehension that the ordeal was over. The impossible, the + miraculous, had been accomplished.(5) + </p> + <p> + Swiftly as steam could carry it—slowly enough we should think it + to-day—the news was heralded to all the world. It was received in + Europe with incredulity, which vanished before repeated experiments. + Surgeons were loath to believe that ether, a drug that had long held a + place in the subordinate armamentarium of the physician, could accomplish + such a miracle. But scepticism vanished before the tests which any surgeon + might make, and which surgeons all over the world did make within the next + few weeks. Then there came a lingering outcry from a few surgeons, notably + some of the Parisians, that the shock of pain was beneficial to the + patient, hence that anaesthesia—as Dr. Oliver Wendell Holmes had + christened the new method—was a procedure not to be advised. Then, + too, there came a hue-and-cry from many a pulpit that pain was God-given, + and hence, on moral grounds, to be clung to rather than renounced. But the + outcry of the antediluvians of both hospital and pulpit quickly received + its quietus; for soon it was clear that the patient who did not suffer the + shock of pain during an operation rallied better than the one who did so + suffer, while all humanity outside the pulpit cried shame to the spirit + that would doom mankind to suffer needless agony. And so within a few + months after that initial operation at the Boston Hospital in 1846, ether + had made good its conquest of pain throughout the civilized world. Only by + the most active use of the imagination can we of this present day realize + the full meaning of that victory. + </p> + <p> + It remains to be added that in the subsequent bickerings over the + discovery—such bickerings as follow every great advance—two + other names came into prominent notice as sharers in the glory of the new + method. Both these were Americans—the one, Dr. Charles T. Jackson, + of Boston; the other, Dr. Crawford W. Long, of Alabama. As to Dr. Jackson, + it is sufficient to say that he seems to have had some vague inkling of + the peculiar properties of ether before Morton's discovery. He even + suggested the use of this drug to Morton, not knowing that Morton had + already tried it; but this is the full measure of his association with the + discovery. Hence it is clear that Jackson's claim to equal share with + Morton in the discovery was unwarranted, not to say absurd. + </p> + <p> + Dr. Long's association with the matter was far different and altogether + honorable. By one of those coincidences so common in the history of + discovery, he was experimenting with ether as a pain-destroyer + simultaneously with Morton, though neither so much as knew of the + existence of the other. While a medical student he had once inhaled ether + for the intoxicant effects, as other medical students were wont to do, and + when partially under influence of the drug he had noticed that a chance + blow to his shins was painless. This gave him the idea that ether might be + used in surgical operations; and in subsequent years, in the course of his + practice in a small Georgia town, he put the idea into successful + execution. There appears to be no doubt whatever that he performed + successful minor operations under ether some two or three years before + Morton's final demonstration; hence that the merit of first using the + drug, or indeed any drug, in this way belongs to him. But, unfortunately, + Dr. Long did not quite trust the evidence of his own experiments. Just at + that time the medical journals were full of accounts of experiments in + which painless operations were said to be performed through practice of + hypnotism, and Dr. Long feared that his own success might be due to an + incidental hypnotic influence rather than to the drug. Hence he delayed + announcing his apparent discovery until he should have opportunity for + further tests—and opportunities did not come every day to the + country practitioner. And while he waited, Morton anticipated him, and the + discovery was made known to the world without his aid. It was a true + scientific caution that actuated Dr. Long to this delay, but the caution + cost him the credit, which might otherwise have been his, of giving to the + world one of the greatest blessings—dare we not, perhaps, say the + very greatest?—that science has ever conferred upon humanity. + </p> + <p> + A few months after the use of ether became general, the Scotch surgeon Sir + J. Y. Simpson(6) discovered that another drug, chloroform, could be + administered with similar effects; that it would, indeed, in many cases + produce anaesthesia more advantageously even than ether. From that day + till this surgeons have been more or less divided in opinion as to the + relative merits of the two drugs; but this fact, of course, has no bearing + whatever upon the merit of the first discovery of the method of + anaesthesia. Even had some other drug subsequently quite banished ether, + the honor of the discovery of the beneficent method of anaesthesia would + have been in no wise invalidated. And despite all cavillings, it is + unequivocally established that the man who gave that method to the world + was William T. G. Morton. + </p> + <p> + PASTEUR AND THE GERM THEORY OF DISEASE + </p> + <p> + The discovery of the anaesthetic power of drugs was destined presently, in + addition to its direct beneficences, to aid greatly in the progress of + scientific medicine, by facilitating those experimental studies of animals + from which, before the day of anaesthesia, many humane physicians were + withheld, and which in recent years have led to discoveries of such + inestimable value to humanity. But for the moment this possibility was + quite overshadowed by the direct benefits of anaesthesia, and the long + strides that were taken in scientific medicine during the first fifteen + years after Morton's discovery were mainly independent of such aid. These + steps were taken, indeed, in a field that at first glance might seem to + have a very slight connection with medicine. Moreover, the chief worker in + the field was not himself a physician. He was a chemist, and the work in + which he was now engaged was the study of alcoholic fermentation in vinous + liquors. Yet these studies paved the way for the most important advances + that medicine has made in any century towards the plane of true science; + and to this man more than to any other single individual—it might + almost be said more than to all other individuals—was due this + wonderful advance. It is almost superfluous to add that the name of this + marvellous chemist was Louis Pasteur. + </p> + <p> + The studies of fermentation which Pasteur entered upon in 1854 were aimed + at the solution of a controversy that had been waging in the scientific + world with varying degrees of activity for a quarter of a century. Back in + the thirties, in the day of the early enthusiasm over the perfected + microscope, there had arisen a new interest in the minute forms of life + which Leeuwenhoek and some of the other early workers with the lens had + first described, and which now were shown to be of almost universal + prevalence. These minute organisms had been studied more or less by a host + of observers, but in particular by the Frenchman Cagniard Latour and the + German of cell-theory fame, Theodor Schwann. These men, working + independently, had reached the conclusion, about 1837, that the + micro-organisms play a vastly more important role in the economy of nature + than any one previously had supposed. They held, for example, that the + minute specks which largely make up the substance of yeast are living + vegetable organisms, and that the growth of these organisms is the cause + of the important and familiar process of fermentation. They even came to + hold, at least tentatively, the opinion that the somewhat similar + micro-organisms to be found in all putrefying matter, animal or vegetable, + had a causal relation to the process of putrefaction. + </p> + <p> + This view, particularly as to the nature of putrefaction, was expressed + even more outspokenly a little later by the French botanist Turpin. Views + so supported naturally gained a following; it was equally natural that so + radical an innovation should be antagonized. In this case it chanced that + one of the most dominating scientific minds of the time, that of Liebig, + took a firm and aggressive stand against the new doctrine. In 1839 he + promulgated his famous doctrine of fermentation, in which he stood out + firmly against any "vitalistic" explanation of the phenomena, alleging + that the presence of micro-organisms in fermenting and putrefying + substances was merely incidental, and in no sense causal. This opinion of + the great German chemist was in a measure substantiated by experiments of + his compatriot Helmholtz, whose earlier experiments confirmed, but later + ones contradicted, the observations of Schwann, and this combined + authority gave the vitalistic conception a blow from which it had not + rallied at the time when Pasteur entered the field. Indeed, it was + currently regarded as settled that the early students of the subject had + vastly over-estimated the importance of micro-organisms. + </p> + <p> + And so it came as a new revelation to the generality of scientists of the + time, when, in 1857 and the succeeding half-decade, Pasteur published the + results of his researches, in which the question had been put to a series + of altogether new tests, and brought to unequivocal demonstration. + </p> + <p> + He proved that the micro-organisms do all that his most imaginative + predecessors had suspected, and more. Without them, he proved, there would + be no fermentation, no putrefaction—no decay of any tissues, except + by the slow process of oxidation. It is the microscopic yeast-plant which, + by seizing on certain atoms of the molecule, liberates the remaining atoms + in the form of carbonic-acid and alcohol, thus effecting fermentation; it + is another microscopic plant—a bacterium, as Devaine had christened + it—which in a similar way effects the destruction of organic + molecules, producing the condition which we call putrefaction. Pasteur + showed, to the amazement of biologists, that there are certain forms of + these bacteria which secure the oxygen which all organic life requires, + not from the air, but by breaking up unstable molecules in which oxygen is + combined; that putrefaction, in short, has its foundation in the + activities of these so-called anaerobic bacteria. + </p> + <p> + In a word, Pasteur showed that all the many familiar processes of the + decay of organic tissues are, in effect, forms of fermentation, and would + not take place at all except for the presence of the living + micro-organisms. A piece of meat, for example, suspended in an atmosphere + free from germs, will dry up gradually, without the slightest sign of + putrefaction, regardless of the temperature or other conditions to which + it may have been subjected. Let us witness one or two series of these + experiments as presented by Pasteur himself in one of his numerous papers + before the Academy of Sciences. + </p> + <p> + EXPERIMENTS WITH GRAPE SUGAR + </p> + <p> + "In the course of the discussion which took place before the Academy upon + the subject of the generation of ferments properly so-called, there was a + good deal said about that of wine, the oldest fermentation known. On this + account I decided to disprove the theory of M. Fremy by a decisive + experiment bearing solely upon the juice of grapes. + </p> + <p> + "I prepared forty flasks of a capacity of from two hundred and fifty to + three hundred cubic centimetres and filled them half full with filtered + grape-must, perfectly clear, and which, as is the case of all acidulated + liquids that have been boiled for a few seconds, remains uncontaminated + although the curved neck of the flask containing them remain constantly + open during several months or years. + </p> + <p> + "In a small quantity of water I washed a part of a bunch of grapes, the + grapes and the stalks together, and the stalks separately. This washing + was easily done by means of a small badger's-hair brush. The washing-water + collected the dust upon the surface of the grapes and the stalks, and it + was easily shown under the microscope that this water held in suspension a + multitude of minute organisms closely resembling either fungoid spores, or + those of alcoholic Yeast, or those of Mycoderma vini, etc. This being + done, ten of the forty flasks were preserved for reference; in ten of the + remainder, through the straight tube attached to each, some drops of the + washing-water were introduced; in a third series of ten flasks a few drops + of the same liquid were placed after it had been boiled; and, finally, in + the ten remaining flasks were placed some drops of grape-juice taken from + the inside of a perfect fruit. In order to carry out this experiment, the + straight tube of each flask was drawn out into a fine and firm point in + the lamp, and then curved. This fine and closed point was filed round near + the end and inserted into the grape while resting upon some hard + substance. When the point was felt to touch the support of the grape it + was by a slight pressure broken off at the point file mark. Then, if care + had been taken to create a slight vacuum in the flask, a drop of the juice + of the grape got into it, the filed point was withdrawn, and the aperture + immediately closed in the alcohol lamp. This decreased pressure of the + atmosphere in the flask was obtained by the following means: After warming + the sides of the flask either in the hands or in the lamp-flame, thus + causing a small quantity of air to be driven out of the end of the curved + neck, this end was closed in the lamp. After the flask was cooled, there + was a tendency to suck in the drop of grape-juice in the manner just + described. + </p> + <p> + "The drop of grape-juice which enters into the flask by this suction + ordinarily remains in the curved part of the tube, so that to mix it with + the must it was necessary to incline the flask so as to bring the must + into contact with the juice and then replace the flask in its normal + position. The four series of comparative experiments produced the + following results: + </p> + <p> + "The first ten flasks containing the grape-must boiled in pure air did not + show the production of any organism. The grape-must could possibly remain + in them for an indefinite number of years. Those in the second series, + containing the water in which the grapes had been washed separately and + together, showed without exception an alcoholic fermentation which in + several cases began to appear at the end of forty-eight hours when the + experiment took place at ordinary summer temperature. At the same time + that the yeast appeared, in the form of white traces, which little by + little united themselves in the form of a deposit on the sides of all the + flasks, there were seen to form little flakes of Mycellium, often as a + single fungoid growth or in combination, these fungoid growths being quite + independent of the must or of any alcoholic yeast. Often, also, the + Mycoderma vini appeared after some days upon the surface of the liquid. + The Vibria and the lactic ferments properly so called did not appear on + account of the nature of the liquid. + </p> + <p> + "The third series of flasks, the washing-water in which had been + previously boiled, remained unchanged, as in the first series. Those of + the fourth series, in which was the juice of the interior of the grapes, + remained equally free from change, although I was not always able, on + account of the delicacy of the experiment, to eliminate every chance of + error. These experiments cannot leave the least doubt in the mind as to + the following facts: + </p> + <p> + "Grape-must, after heating, never ferments on contact with the air, when + the air has been deprived of the germs which it ordinarily holds in a + state of suspension. + </p> + <p> + "The boiled grape-must ferments when there is introduced into it a very + small quantity of water in which the surface of the grapes or their stalks + have been washed. + </p> + <p> + "The grape-must does not ferment when this washing-water has been boiled + and afterwards cooled. + </p> + <p> + "The grape-must does not ferment when there is added to it a small + quantity of the juice of the inside of the grape. + </p> + <p> + "The yeast, therefore, which causes the fermentation of the grapes in the + vintage-tub comes from the outside and not from the inside of the grapes. + Thus is destroyed the hypothesis of MM. Trecol and Fremy, who surmised + that the albuminous matter transformed itself into yeast on account of the + vital germs which were natural to it. With greater reason, therefore, + there is no longer any question of the theory of Liebig of the + transformation of albuminoid matter into ferments on account of the + oxidation." + </p> + <p> + FOREIGN ORGANISMS AND THE WORT OF BEER + </p> + <p> + "The method which I have just followed," Pasteur continues, "in order to + show that there exists a correlation between the diseases of beer and + certain microscopic organisms leaves no room for doubt, it seems to me, in + regard to the principles I am expounding. + </p> + <p> + "Every time that the microscope reveals in the leaven, and especially in + the active yeast, the production of organisms foreign to the alcoholic + yeast properly so called, the flavor of the beer leaves something to be + desired, much or little, according to the abundance and the character of + these little germs. Moreover, when a finished beer of good quality loses + after a time its agreeable flavor and becomes sour, it can be easily shown + that the alcoholic yeast deposited in the bottles or the casks, although + originally pure, at least in appearance, is found to be contaminated + gradually with these filiform or other ferments. All this can be deduced + from the facts already given, but some critics may perhaps declare that + these foreign ferments are the consequences of the diseased condition, + itself produced by unknown causes. + </p> + <p> + "Although this gratuitous hypothesis may be difficult to uphold, I will + endeavor to corroborate the preceding observations by a clearer method of + investigation. This consists in showing that the beer never has any + unpleasant taste in all cases when the alcoholic ferment properly so + called is not mixed with foreign ferments; that it is the same in the case + of wort, and that wort, liable to changes as it is, can be preserved + unaltered if it is kept from those microscopic parasites which find in it + a suitable nourishment and a field for growth. + </p> + <p> + "The employment of this second method has, moreover, the advantage of + proving with certainty the proposition that I advanced at first—namely, + that the germs of these organisms are derived from the dust of the + atmosphere, carried about and deposited upon all objects, or scattered + over the utensils and the materials used in a brewery-materials naturally + charged with microscopic germs, and which the various operations in the + store-rooms and the malt-house may multiply indefinitely. + </p> + <p> + "Let us take a glass flask with a long neck of from two hundred and fifty + to three hundred cubic centimetres capacity, and place in it some wort, + with or without hops, and then in the flame of a lamp draw out the neck of + the flask to a fine point, afterwards heating the liquid until the steam + comes out of the end of the neck. It can then be allowed to cool without + any other precautions; but for additional safety there can be introduced + into the little point a small wad of asbestos at the moment that the flame + is withdrawn from beneath the flask. Before thus placing the asbestos it + also can be passed through the flame, as well as after it has been put + into the end of the tube. The air which then first re-enters the flask + will thus come into contact with the heated glass and the heated liquid, + so as to destroy the vitality of any dust germs that may exist in the air. + The air itself will re-enter very gradually, and slowly enough to enable + any dust to be taken up by the drop of water which the air forces up the + curvature of the tube. Ultimately the tube will be dry, but the + re-entering of the air will be so slow that the particles of dust will + fall upon the sides of the tube. The experiments show that with this kind + of vessel, allowing free communication with the air, and the dust not + being allowed to enter, the dust will not enter at all events for a period + of ten or twelve years, which has been the longest period devoted to these + trials; and the liquid, if it were naturally limpid, will not be in the + least polluted neither on its surface nor in its mass, although the + outside of the flask may become thickly coated with dust. This is a most + irrefutable proof of the impossibility of dust getting inside the flask. + </p> + <p> + "The wort thus prepared remains uncontaminated indefinitely, in spite of + its susceptibility to change when exposed to the air under conditions + which allow it to gather the dusty particles which float in the + atmosphere. It is the same in the case of urine, beef-tea, and grape-must, + and generally with all those putrefactable and fermentable liquids which + have the property when heated to boiling-point of destroying the vitality + of dust germs."(7) + </p> + <p> + There was nothing in these studies bearing directly upon the question of + animal diseases, yet before they were finished they had stimulated + progress in more than one field of pathology. At the very outset they + sufficed to start afresh the inquiry as to the role played by + micro-organisms in disease. In particular they led the French physician + Devaine to return to some interrupted studies which he had made ten years + before in reference to the animal disease called anthrax, or splenic + fever, a disease that cost the farmers of Europe millions of francs + annually through loss of sheep and cattle. In 1850 Devaine had seen + multitudes of bacteria in the blood of animals who had died of anthrax, + but he did not at that time think of them as having a causal relation to + the disease. Now, however, in 1863, stimulated by Pasteur's new + revelations regarding the power of bacteria, he returned to the subject, + and soon became convinced, through experiments by means of inoculation, + that the microscopic organisms he had discovered were the veritable and + the sole cause of the infectious disease anthrax. + </p> + <p> + The publication of this belief in 1863 aroused a furor of controversy. + That a microscopic vegetable could cause a virulent systemic disease was + an idea altogether too startling to be accepted in a day, and the + generality of biologists and physicians demanded more convincing proofs + than Devaine as yet was able to offer. + </p> + <p> + Naturally a host of other investigators all over the world entered the + field. Foremost among these was the German Dr. Robert Koch, who soon + corroborated all that Devaine had observed, and carried the experiments + further in the direction of the cultivation of successive generations of + the bacteria in artificial media, inoculations being made from such pure + cultures of the eighth generation, with the astonishing result that + animals thus inoculated succumbed to the disease. + </p> + <p> + Such experiments seem demonstrative, yet the world was unconvinced, and in + 1876, while the controversy was still at its height, Pasteur was prevailed + upon to take the matter in hand. The great chemist was becoming more and + more exclusively a biologist as the years passed, and in recent years his + famous studies of the silk-worm diseases, which he proved due to bacterial + infection, and of the question of spontaneous generation, had given him + unequalled resources in microscopical technique. And so when, with the aid + of his laboratory associates Duclaux and Chamberland and Roux, he took up + the mooted anthrax question the scientific world awaited the issue with + bated breath. And when, in 1877, Pasteur was ready to report on his + studies of anthrax, he came forward with such a wealth of demonstrative + experiments—experiments the rigid accuracy of which no one would for + a moment think of questioning—going to prove the bacterial origin of + anthrax, that scepticism was at last quieted for all time to come. + </p> + <p> + Henceforth no one could doubt that the contagious disease anthrax is due + exclusively to the introduction into an animal's system of a specific germ—a + microscopic plant—which develops there. And no logical mind could + have a reasonable doubt that what is proved true of one infectious disease + would some day be proved true also of other, perhaps of all, forms of + infectious maladies. + </p> + <p> + Hitherto the cause of contagion, by which certain maladies spread from + individual to individual, had been a total mystery, quite unillumined by + the vague terms "miasm," "humor," "virus," and the like cloaks of + ignorance. Here and there a prophet of science, as Schwann and Henle, had + guessed the secret; but guessing, in science, is far enough from knowing. + Now, for the first time, the world KNEW, and medicine had taken another + gigantic stride towards the heights of exact science. + </p> + <p> + LISTER AND ANTISEPTIC SURGERY + </p> + <p> + Meantime, in a different though allied field of medicine there had been a + complementary growth that led to immediate results of even more practical + importance. I mean the theory and practice of antisepsis in surgery. This + advance, like the other, came as a direct outgrowth of Pasteur's + fermentation studies of alcoholic beverages, though not at the hands of + Pasteur himself. Struck by the boundless implications of Pasteur's + revelations regarding the bacteria, Dr. Joseph Lister (the present Lord + Lister), then of Glasgow, set about as early as 1860 to make a wonderful + application of these ideas. If putrefaction is always due to bacterial + development, he argued, this must apply as well to living as to dead + tissues; hence the putrefactive changes which occur in wounds and after + operations on the human subject, from which blood-poisoning so often + follows, might be absolutely prevented if the injured surfaces could be + kept free from access of the germs of decay. + </p> + <p> + In the hope of accomplishing this result, Lister began experimenting with + drugs that might kill the bacteria without injury to the patient, and with + means to prevent further access of germs once a wound was freed from them. + How well he succeeded all the world knows; how bitterly he was antagonized + for about a score of years, most of the world has already forgotten. As + early as 1867 Lister was able to publish results pointing towards success + in his great project; yet so incredulous were surgeons in general that + even some years later the leading surgeons on the Continent had not so + much as heard of his efforts. In 1870 the soldiers of Paris died, as of + old, of hospital gangrene; and when, in 1871, the French surgeon Alphonse + Guerin, stimulated by Pasteur's studies, conceived the idea of dressing + wounds with cotton in the hope of keeping germs from entering them, he was + quite unaware that a British contemporary had preceded him by a full + decade in this effort at prevention and had made long strides towards + complete success. Lister's priority, however, and the superiority of his + method, were freely admitted by the French Academy of Sciences, which in + 1881 officially crowned his achievement, as the Royal Society of London + had done the year before. + </p> + <p> + By this time, to be sure, as everybody knows, Lister's new methods had + made their way everywhere, revolutionizing the practice of surgery and + practically banishing from the earth maladies that hitherto had been the + terror of the surgeon and the opprobrium of his art. And these bedside + studies, conducted in the end by thousands of men who had no knowledge of + microscopy, had a large share in establishing the general belief in the + causal relation that micro-organisms bear to disease, which by about the + year 1880 had taken possession of the medical world. But they did more; + they brought into equal prominence the idea that, the cause of a diseased + condition being known, it maybe possible as never before to grapple with + and eradicate that condition. + </p> + <p> + PREVENTIVE INOCULATION + </p> + <p> + The controversy over spontaneous generation, which, thanks to Pasteur and + Tyndall, had just been brought to a termination, made it clear that no + bacterium need be feared where an antecedent bacterium had not found + lodgment; Listerism in surgery had now shown how much might be + accomplished towards preventing the access of germs to abraded surfaces of + the body and destroying those that already had found lodgment there. As + yet, however, there was no inkling of a way in which a corresponding + onslaught might be made upon those other germs which find their way into + the animal organism by way of the mouth and the nostrils, and which, as + was now clear, are the cause of those contagious diseases which, first and + last, claim so large a proportion of mankind for their victims. How such + means might be found now became the anxious thought of every imaginative + physician, of every working microbiologist. + </p> + <p> + As it happened, the world was not kept long in suspense. Almost before the + proposition had taken shape in the minds of the other leaders, Pasteur had + found a solution. Guided by the empirical success of Jenner, he, like many + others, had long practised inoculation experiments, and on February 9, + 1880, he announced to the French Academy of Sciences that he had found a + method of so reducing the virulence of a disease germ that when introduced + into the system of a susceptible animal it produced only a mild form of + the disease, which, however, sufficed to protect against the usual + virulent form exactly as vaccinia protects against small-pox. The + particular disease experimented with was that infectious malady of poultry + known familiarly as "chicken cholera." In October of the same year Pasteur + announced the method by which this "attenuation of the virus," as he + termed it, had been brought about—by cultivation of the disease + germs in artificial media, exposed to the air, and he did not hesitate to + assert his belief that the method would prove "susceptible of + generalization"—that is to say, of application to other diseases + than the particular one in question. + </p> + <p> + Within a few months he made good this prophecy, for in February, 1881, he + announced to the Academy that with the aid, as before, of his associates + MM. Chamberland and Roux, he had produced an attenuated virus of the + anthrax microbe by the use of which, as he affirmed with great confidence, + he could protect sheep, and presumably cattle, against that fatal malady. + "In some recent publications," said Pasteur, "I announced the first case + of the attenuation of a virus by experimental methods only. Formed of a + special microbe of an extreme minuteness, this virus may be multiplied by + artificial culture outside the animal body. These cultures, left alone + without any possible external contamination, undergo, in the course of + time, modifications of their virulency to a greater or less extent. The + oxygen of the atmosphere is said to be the chief cause of these + attenuations—that is, this lessening of the facilities of + multiplication of the microbe; for it is evident that the difference of + virulence is in some way associated with differences of development in the + parasitic economy. + </p> + <p> + "There is no need to insist upon the interesting character of these + results and the deductions to be made therefrom. To seek to lessen the + virulence by rational means would be to establish, upon an experimental + basis, the hope of preparing from an active virus, easily cultivated + either in the human or animal body, a vaccine-virus of restrained + development capable of preventing the fatal effects of the former. + Therefore, we have applied all our energies to investigate the possible + generalizing action of atmospheric oxygen in the attenuation of virus. + </p> + <p> + "The anthrax virus, being one that has been most carefully studied, seemed + to be the first that should attract our attention. Every time, however, we + encountered a difficulty. Between the microbe of chicken cholera and the + microbe of anthrax there exists an essential difference which does not + allow the new experiment to be verified by the old. The microbes of + chicken cholera do not, in effect, seem to resolve themselves, in their + culture, into veritable germs. The latter are merely cells, or + articulations always ready to multiply by division, except when the + particular conditions in which they become true germs are known. + </p> + <p> + "The yeast of beer is a striking example of these cellular productions, + being able to multiply themselves indefinitely without the apparition of + their original spores. There exist many mucedines (Mucedinae?) of tubular + mushrooms, which in certain conditions of culture produce a chain of more + or less spherical cells called Conidae. The latter, detached from their + branches, are able to reproduce themselves in the form of cells, without + the appearance, at least with a change in the conditions of culture, of + the spores of their respective mucedines. These vegetable organisms can be + compared to plants which are cultivated by slipping, and to produce which + it is not necessary to have the fruits or the seeds of the mother plant. + </p> + <p> + "The anthrax bacterium, in its artificial cultivation, behaves very + differently. Its mycelian filaments, if one may so describe them, have + been produced scarcely for twenty-four or forty-eight hours when they are + seen to transform themselves, those especially which are in free contact + with the air, into very refringent corpuscles, capable of gradually + isolating themselves into true germs of slight organization. Moreover, + observation shows that these germs, formed so quickly in the culture, do + not undergo, after exposure for a time to atmospheric air, any change + either in their vitality or their virulence. I was able to present to the + Academy a tube containing some spores of anthrax bacteria produced four + years ago, on March 21, 1887. Each year the germination of these little + corpuscles has been tried, and each year the germination has been + accomplished with the same facility and the same rapidity as at first. + Each year also the virulence of the new cultures has been tested, and they + have not shown any visible falling off. Therefore, how can we experiment + with the action of the air upon the anthrax virus with any expectation of + making it less virulent? + </p> + <p> + "The crucial difficulty lies perhaps entirely in this rapid reproduction + of the bacteria germs which we have just related. In its form of a + filament, and in its multiplication by division, is not this organism at + all points comparable with the microbe of the chicken cholera? + </p> + <p> + "That a germ, properly so called, that a seed, does not suffer any + modification on account of the air is easily conceived; but it is + conceivable not less easily that if there should be any change it would + occur by preference in the case of a mycelian fragment. It is thus that a + slip which may have been abandoned in the soil in contact with the air + does not take long to lose all vitality, while under similar conditions a + seed is preserved in readiness to reproduce the plant. If these views have + any foundation, we are led to think that in order to prove the action of + the air upon the anthrax bacteria it will be indispensable to submit to + this action the mycelian development of the minute organism under + conditions where there cannot be the least admixture of corpuscular germs. + Hence the problem of submitting the bacteria to the action of oxygen comes + back to the question of presenting entirely the formation of spores. The + question being put in this way, we are beginning to recognize that it is + capable of being solved. + </p> + <p> + "We can, in fact, prevent the appearance of spores in the artificial + cultures of the anthrax parasite by various artifices. At the lowest + temperature at which this parasite can be cultivated—that is to say, + about +16 degrees Centigrade—the bacterium does not produce germs—at + any rate, for a very long time. The shapes of the minute microbe at this + lowest limit of its development are irregular, in the form of balls and + pears—in a word, they are monstrosities—but they are without + spores. In the last regard also it is the same at the highest temperatures + at which the parasite can be cultivated, temperatures which vary slightly + according to the means employed. In neutral chicken bouillon the bacteria + cannot be cultivated above 45 degrees. Culture, however, is easy and + abundant at 42 to 43 degrees, but equally without any formation of spores. + Consequently a culture of mycelian bacteria can be kept entirely free from + germs while in contact with the open air at a temperature of from 42 to 43 + degrees Centigrade. Now appear the three remarkable results. After about + one month of waiting the culture dies—that is to say, if put into a + fresh bouillon it becomes absolutely sterile. + </p> + <p> + "So much for the life and nutrition of this organism. In respect to its + virulence, it is an extraordinary fact that it disappears entirely after + eight days' culture at 42 to 43 degrees Centigrade, or, at any rate, the + cultures are innocuous for the guinea-pig, the rabbit, and the sheep, the + three kinds of animals most apt to contract anthrax. We are thus able to + obtain, not only the attenuation of the virulence, but also its complete + suppression by a simple method of cultivation. Moreover, we see also the + possibility of preserving and cultivating the terrible microbe in an + inoffensive state. What is it that happens in these eight days at 43 + degrees that suffices to take away the virulence of the bacteria? Let us + remember that the microbe of chicken cholera dies in contact with the air, + in a period somewhat protracted, it is true, but after successive + attenuations. Are we justified in thinking that it ought to be the same in + regard to the microbe of anthrax? This hypothesis is confirmed by + experiment. Before the disappearance of its virulence the anthrax microbe + passes through various degrees of attenuation, and, moreover, as is also + the case with the microbe of chicken cholera, each of these attenuated + states of virulence can be obtained by cultivation. Moreover, since, + according to one of our recent Communications, anthrax is not recurrent, + each of our attenuated anthrax microbes is, for the better-developed + microbe, a vaccine—that is to say, a virus producing a + less-malignant malady. What, therefore, is easier than to find in these a + virus that will infect with anthrax sheep, cows, and horses, without + killing them, and ultimately capable of warding off the mortal malady? We + have practised this experiment with great success upon sheep, and when the + season comes for the assembling of the flocks at Beauce we shall try the + experiment on a larger scale. + </p> + <p> + "Already M. Toussaint has announced that sheep can be saved by preventive + inoculations; but when this able observer shall have published his + results; on the subject of which we have made such exhaustive studies, as + yet unpublished, we shall be able to see the whole difference which exists + between the two methods—the uncertainty of the one and the certainty + of the other. That which we announce has, moreover, the very great + advantage of resting upon the existence of a poison vaccine cultivable at + will, and which can be increased indefinitely in the space of a few hours + without having recourse to infected blood."(8) + </p> + <p> + This announcement was immediately challenged in a way that brought it to + the attention of the entire world. The president of an agricultural + society, realizing the enormous importance of the subject, proposed to + Pasteur that his alleged discovery should be submitted to a decisive + public test. He proposed to furnish a drove of fifty sheep half of which + were to be inoculated with the attenuated virus of Pasteur. Subsequently + all the sheep were to be inoculated with virulent virus, all being kept + together in one pen under precisely the same conditions. The "protected" + sheep were to remain healthy; the unprotected ones to die of anthrax; so + read the terms of the proposition. Pasteur accepted the challenge; he even + permitted a change in the programme by which two goats were substituted + for two of the sheep, and ten cattle added, stipulating, however, that + since his experiments had not yet been extended to cattle these should not + be regarded as falling rigidly within the terms of the test. + </p> + <p> + It was a test to try the soul of any man, for all the world looked on + askance, prepared to deride the maker of so preposterous a claim as soon + as his claim should be proved baseless. Not even the fame of Pasteur could + make the public at large, lay or scientific, believe in the possibility of + what he proposed to accomplish. There was time for all the world to be + informed of the procedure, for the first "preventive" inoculation—or + vaccination, as Pasteur termed it—was made on May 5th, the second on + May 17th, and another interval of two weeks must elapse before the final + inoculations with the unattenuated virus. Twenty-four sheep, one goat, and + five cattle were submitted to the preliminary vaccinations. Then, on May + 31 st, all sixty of the animals were inoculated, a protected and + unprotected one alternately, with an extremely virulent culture of anthrax + microbes that had been in Pasteur's laboratory since 1877. This + accomplished, the animals were left together in one enclosure to await the + issue. + </p> + <p> + Two days later, June 2d, at the appointed hour of rendezvous, a vast + crowd, composed of veterinary surgeons, newspaper correspondents, and + farmers from far and near, gathered to witness the closing scenes of this + scientific tourney. What they saw was one of the most dramatic scenes in + the history of peaceful science—a scene which, as Pasteur declared + afterwards, "amazed the assembly." Scattered about the enclosure, dead, + dying, or manifestly sick unto death, lay the unprotected animals, one and + all, while each and every "protected" animal stalked unconcernedly about + with every appearance of perfect health. Twenty of the sheep and the one + goat were already dead; two other sheep expired under the eyes of the + spectators; the remaining victims lingered but a few hours longer. Thus in + a manner theatrical enough, not to say tragic, was proclaimed the + unequivocal victory of science. Naturally enough, the unbelievers struck + their colors and surrendered without terms; the principle of protective + vaccination, with a virus experimentally prepared in the laboratory, was + established beyond the reach of controversy. + </p> + <p> + That memorable scientific battle marked the beginning of a new era in + medicine. It was a foregone conclusion that the principle thus established + would be still further generalized; that it would be applied to human + maladies; that in all probability it would grapple successfully, sooner or + later, with many infectious diseases. That expectation has advanced + rapidly towards realization. Pasteur himself made the application to the + human subject in the disease hydrophobia in 1885, since which time that + hitherto most fatal of maladies has largely lost its terrors. Thousands of + persons bitten by mad dogs have been snatched from the fatal consequences + of that mishap by this method at the Pasteur Institute in Paris, and at + the similar institutes, built on the model of this parent one, that have + been established all over the world in regions as widely separated as New + York and Nha-Trang. + </p> + <p> + SERUM-THERAPY + </p> + <p> + In the production of the rabies vaccine Pasteur and his associates + developed a method of attenuation of a virus quite different from that + which had been employed in the case of the vaccines of chicken cholera and + of anthrax. The rabies virus was inoculated into the system of guinea-pigs + or rabbits and, in effect, cultivated in the systems of these animals. The + spinal cord of these infected animals was found to be rich in the virus, + which rapidly became attenuated when the cord was dried in the air. The + preventive virus, of varying strengths, was made by maceration of these + cords at varying stages of desiccation. This cultivation of a virus within + the animal organism suggested, no doubt, by the familiar Jennerian method + of securing small-pox vaccine, was at the same time a step in the + direction of a new therapeutic procedure which was destined presently to + become of all-absorbing importance—the method, namely, of so-called + serum-therapy, or the treatment of a disease with the blood serum of an + animal that has been subjected to protective inoculation against that + disease. + </p> + <p> + The possibility of such a method was suggested by the familiar + observation, made by Pasteur and numerous other workers, that animals of + different species differ widely in their susceptibility to various + maladies, and that the virus of a given disease may become more and more + virulent when passed through the systems of successive individuals of one + species, and, contrariwise, less and less virulent when passed through the + systems of successive individuals of another species. These facts + suggested the theory that the blood of resistant animals might contain + something directly antagonistic to the virus, and the hope that this + something might be transferred with curative effect to the blood of an + infected susceptible animal. Numerous experimenters all over the world + made investigations along the line of this alluring possibility, the + leaders perhaps being Drs. Behring and Kitasato, closely followed by Dr. + Roux and his associates of the Pasteur Institute of Paris. Definite + results were announced by Behring in 1892 regarding two important diseases—tetanus + and diphtheria—but the method did not come into general notice until + 1894, when Dr. Roux read an epoch-making paper on the subject at the + Congress of Hygiene at Buda-Pesth. + </p> + <p> + In this paper Dr. Roux, after adverting to the labors of Behring, Ehrlich, + Boer, Kossel, and Wasserman, described in detail the methods that had been + developed at the Pasteur Institute for the development of the curative + serum, to which Behring had given the since-familiar name antitoxine. The + method consists, first, of the cultivation, for some months, of the + diphtheria bacillus (called the Klebs-Loeffler bacillus, in honor of its + discoverers) in an artificial bouillon, for the development of a powerful + toxine capable of giving the disease in a virulent form. + </p> + <p> + This toxine, after certain details of mechanical treatment, is injected in + small but increasing doses into the system of an animal, care being taken + to graduate the amount so that the animal does not succumb to the disease. + After a certain course of this treatment it is found that a portion of + blood serum of the animal so treated will act in a curative way if + injected into the blood of another animal, or a human patient, suffering + with diphtheria. In other words, according to theory, an antitoxine has + been developed in the system of the animal subjected to the progressive + inoculations of the diphtheria toxine. In Dr. Roux's experience the animal + best suited for the purpose is the horse, though almost any of the + domesticated animals will serve the purpose. + </p> + <p> + But Dr. Roux's paper did not stop with the description of laboratory + methods. It told also of the practical application of the serum to the + treatment of numerous cases of diphtheria in the hospitals of Paris—applications + that had met with a gratifying measure of success. He made it clear that a + means had been found of coping successfully with what had been one of the + most virulent and intractable of the diseases of childhood. Hence it was + not strange that his paper made a sensation in all circles, medical and + lay alike. + </p> + <p> + Physicians from all over the world flocked to Paris to learn the details + of the open secret, and within a few months the new serum-therapy had an + acknowledged standing with the medical profession everywhere. What it had + accomplished was regarded as but an earnest of what the new method might + accomplish presently when applied to the other infectious diseases. + </p> + <p> + Efforts at such applications were immediately begun in numberless + directions—had, indeed, been under way in many a laboratory for some + years before. It is too early yet to speak of the results in detail. But + enough has been done to show that this method also is susceptible of the + widest generalization. It is not easy at the present stage to sift that + which is tentative from that which will be permanent; but so great an + authority as Behring does not hesitate to affirm that today we possess, in + addition to the diphtheria antitoxine, equally specific antitoxines of + tetanus, cholera, typhus fever, pneumonia, and tuberculosis—a set of + diseases which in the aggregate account for a startling proportion of the + general death-rate. Then it is known that Dr. Yersin, with the + collaboration of his former colleagues of the Pasteur Institute, has + developed, and has used with success, an antitoxine from the microbe of + the plague which recently ravaged China. + </p> + <p> + Dr. Calmette, another graduate of the Pasteur Institute, has extended the + range of the serum-therapy to include the prevention and treatment of + poisoning by venoms, and has developed an antitoxine that has already + given immunity from the lethal effects of snake bites to thousands of + persons in India and Australia. + </p> + <p> + Just how much of present promise is tentative, just what are the limits of + the methods—these are questions for the future to decide. But, in + any event, there seems little question that the serum treatment will stand + as the culminating achievement in therapeutics of our century. It is the + logical outgrowth of those experimental studies with the microscope begun + by our predecessors of the thirties, and it represents the present + culmination of the rigidly experimental method which has brought medicine + from a level of fanciful empiricism to the plane of a rational + experimental science. + </p> + <p> + <a name="link2H_4_0010" id="link2H_4_0010"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + IX. THE NEW SCIENCE OF EXPERIMENTAL PSYCHOLOGY + </h2> + <h3> + BRAIN AND MIND + </h3> + <p> + A little over a hundred years ago a reform movement was afoot in the world + in the interests of the insane. As was fitting, the movement showed itself + first in America, where these unfortunates were humanely cared for at a + time when their treatment elsewhere was worse than brutal; but England and + France quickly fell into line. The leader on this side of the water was + the famous Philadelphian, Dr. Benjamin Rush, "the Sydenham of America"; in + England, Dr. William Tuke inaugurated the movement; and in France, Dr. + Philippe Pinel, single-handed, led the way. Moved by a common spirit, + though acting quite independently, these men raised a revolt against the + traditional custom which, spurning the insane as demon-haunted outcasts, + had condemned these unfortunates to dungeons, chains, and the lash. + Hitherto few people had thought it other than the natural course of events + that the "maniac" should be thrust into a dungeon, and perhaps chained to + the wall with the aid of an iron band riveted permanently about his neck + or waist. Many an unfortunate, thus manacled, was held to the narrow + limits of his chain for years together in a cell to which full daylight + never penetrated; sometimes—iron being expensive—the chain was + so short that the wretched victim could not rise to the upright posture or + even shift his position upon his squalid pallet of straw. + </p> + <p> + In America, indeed, there being no Middle Age precedents to crystallize + into established customs, the treatment accorded the insane had seldom or + never sunk to this level. Partly for this reason, perhaps, the work of Dr. + Rush at the Philadelphia Hospital, in 1784, by means of which the insane + came to be humanely treated, even to the extent of banishing the lash, has + been but little noted, while the work of the European leaders, though + belonging to later decades, has been made famous. And perhaps this is not + as unjust as it seems, for the step which Rush took, from relatively bad + to good, was a far easier one to take than the leap from atrocities to + good treatment which the European reformers were obliged to compass. In + Paris, for example, Pinel was obliged to ask permission of the authorities + even to make the attempt at liberating the insane from their chains, and, + notwithstanding his recognized position as a leader of science, he gained + but grudging assent, and was regarded as being himself little better than + a lunatic for making so manifestly unwise and hopeless an attempt. Once + the attempt had been made, however, and carried to a successful issue, the + amelioration wrought in the condition of the insane was so patent that the + fame of Pinel's work at the Bicetre and the Salpetriere went abroad apace. + It required, indeed, many years to complete it in Paris, and a lifetime of + effort on the part of Pinel's pupil Esquirol and others to extend the + reform to the provinces; but the epochal turning-point had been reached + with Pinel's labors of the closing years of the eighteenth century. + </p> + <p> + The significance of this wise and humane reform, in the present + connection, is the fact that these studies of the insane gave emphasis to + the novel idea, which by-and-by became accepted as beyond question, that + "demoniacal possession" is in reality no more than the outward expression + of a diseased condition of the brain. This realization made it clear, as + never before, how intimately the mind and the body are linked one to the + other. And so it chanced that, in striking the shackles from the insane, + Pinel and his confreres struck a blow also, unwittingly, at time-honored + philosophical traditions. The liberation of the insane from their dungeons + was an augury of the liberation of psychology from the musty recesses of + metaphysics. Hitherto psychology, in so far as it existed at all, was but + the subjective study of individual minds; in future it must become + objective as well, taking into account also the relations which the mind + bears to the body, and in particular to the brain and nervous system. + </p> + <p> + The necessity for this collocation was advocated quite as earnestly, and + even more directly, by another worker of this period, whose studies were + allied to those of alienists, and who, even more actively than they, + focalized his attention upon the brain and its functions. This earliest of + specialists in brain studies was a German by birth but Parisian by + adoption, Dr. Franz Joseph Gall, originator of the since-notorious system + of phrenology. The merited disrepute into which this system has fallen + through the exposition of peripatetic charlatans should not make us forget + that Dr. Gall himself was apparently a highly educated physician, a + careful student of the brain and mind according to the best light of his + time, and, withal, an earnest and honest believer in the validity of the + system he had originated. The system itself, taken as a whole, was + hopelessly faulty, yet it was not without its latent germ of truth, as + later studies were to show. How firmly its author himself believed in it + is evidenced by the paper which he contributed to the French Academy of + Sciences in 1808. The paper itself was referred to a committee of which + Pinel and Cuvier were members. The verdict of this committee was adverse, + and justly so; yet the system condemned had at least one merit which its + detractors failed to realize. It popularized the conception that the brain + is the organ of mind. Moreover, by its insistence it rallied about it a + band of scientific supporters, chief of whom was Dr. Kaspar Spurzlieim, a + man of no mean abilities, who became the propagandist of phrenology in + England and in America. Of course such advocacy and popularity stimulated + opposition as well, and out of the disputations thus arising there grew + presently a general interest in the brain as the organ of mind, quite + aside from any preconceptions whatever as to the doctrines of Gall and + Spurzheim. + </p> + <p> + Prominent among the unprejudiced class of workers who now appeared was the + brilliant young Frenchman Louis Antoine Desmoulins, who studied first + under the tutorage of the famous Magendie, and published jointly with him + a classical work on the nervous system of vertebrates in 1825. Desmoulins + made at least one discovery of epochal importance. He observed that the + brains of persons dying in old age were lighter than the average and gave + visible evidence of atrophy, and he reasoned that such decay is a normal + accompaniment of senility. No one nowadays would question the accuracy of + this observation, but the scientific world was not quite ready for it in + 1825; for when Desmoulins announced his discovery to the French Academy, + that august and somewhat patriarchal body was moved to quite unscientific + wrath, and forbade the young iconoclast the privilege of further hearings. + From which it is evident that the partially liberated spirit of the new + psychology had by no means freed itself altogether, at the close of the + first quarter of the nineteenth century, from the metaphysical cobwebs of + its long incarceration. + </p> + <p> + FUNCTIONS OF THE NERVES + </p> + <p> + While studies of the brain were thus being inaugurated, the nervous + system, which is the channel of communication between the brain and the + outside world, was being interrogated with even more tangible results. The + inaugural discovery was made in 1811 by Dr. (afterwards Sir Charles) + Bell,(1) the famous English surgeon and experimental physiologist. It + consisted of the observation that the anterior roots of the spinal nerves + are given over to the function of conveying motor impulses from the brain + outward, whereas the posterior roots convey solely sensory impulses to the + brain from without. Hitherto it had been supposed that all nerves have a + similar function, and the peculiar distribution of the spinal nerves had + been an unsolved puzzle. + </p> + <p> + Bell's discovery was epochal; but its full significance was not + appreciated for a decade, nor, indeed, was its validity at first admitted. + In Paris, in particular, then the court of final appeal in all matters + scientific, the alleged discovery was looked at askance, or quite ignored. + But in 1823 the subject was taken up by the recognized leader of French + physiology—Francois Magendie—in the course of his + comprehensive experimental studies of the nervous system, and Bell's + conclusions were subjected to the most rigid experimental tests and found + altogether valid. Bell himself, meanwhile, had turned his attention to the + cranial nerves, and had proved that these also are divisible into two sets—sensory + and motor. Sometimes, indeed, the two sets of filaments are combined into + one nerve cord, but if traced to their origin these are found to arise + from different brain centres. Thus it was clear that a hitherto + unrecognized duality of function pertains to the entire extra-cranial + nervous system. Any impulse sent from the periphery to the brain must be + conveyed along a perfectly definite channel; the response from the brain, + sent out to the peripheral muscles, must traverse an equally definite and + altogether different course. If either channel is interrupted—as by + the section of its particular nerve tract—the corresponding message + is denied transmission as effectually as an electric current is stopped by + the section of the transmitting wire. + </p> + <p> + Experimenters everywhere soon confirmed the observations of Bell and + Magendie, and, as always happens after a great discovery, a fresh impulse + was given to investigations in allied fields. Nevertheless, a full decade + elapsed before another discovery of comparable importance was made. Then + Marshall Hall, the most famous of English physicians of his day, made his + classical observations on the phenomena that henceforth were to be known + as reflex action. In 1832, while experimenting one day with a decapitated + newt, he observed that the headless creature's limbs would contract in + direct response to certain stimuli. Such a response could no longer be + secured if the spinal nerves supplying a part were severed. Hence it was + clear that responsive centres exist in the spinal cord capable of + receiving a sensory message and of transmitting a motor impulse in reply—a + function hitherto supposed to be reserved for the brain. Further studies + went to show that such phenomena of reflex action on the part of centres + lying outside the range of consciousness, both in the spinal cord and in + the brain itself, are extremely common; that, in short, they enter + constantly into the activities of every living organism and have a most + important share in the sum total of vital movements. Hence, Hall's + discovery must always stand as one of the great mile-stones of the advance + of neurological science. + </p> + <p> + Hall gave an admirably clear and interesting account of his experiments + and conclusions in a paper before the Royal Society, "On the Reflex + Functions of the Medulla Oblongata and the Medulla Spinalis," from which, + as published in the Transactions of the society for 1833, we may quote at + some length: + </p> + <p> + "In the entire animal, sensation and voluntary motion, functions of the + cerebrum, combine with the functions of the medulla oblongata and medulla + spinalis, and may therefore render it difficult or impossible to determine + those which are peculiar to each; if, in an animal deprived of the brain, + the spinal marrow or the nerves supplying the muscles be stimulated, those + muscles, whether voluntary or respiratory, are equally thrown into + contraction, and, it may be added, equally in the complete and in the + mutilated animal; and, in the case of the nerves, equally in limbs + connected with and detached from the spinal marrow. + </p> + <p> + "The operation of all these various causes may be designated centric, as + taking place AT, or at least in a direction FROM, central parts of the + nervous system. But there is another function the phenomena of which are + of a totally different order and obey totally different laws, being + excited by causes in a situation which is EXCENTRIC in the nervous system—that + is, distant from the nervous centres. This mode of action has not, I + think, been hitherto distinctly understood by physiologists. + </p> + <p> + "Many of the phenomena of this principle of action, as they occur in the + limbs, have certainly been observed. But, in the first place, this + function is by no means confined to the limbs; for, while it imparts to + each muscle its appropriate tone, and to each system of muscles its + appropriate equilibrium or balance, it performs the still more important + office of presiding over the orifices and terminations of each of the + internal canals in the animal economy, giving them their due form and + action; and, in the second place, in the instances in which the phenomena + of this function have been noticed, they have been confounded, as I have + stated, with those of sensation and volition; or, if they have been + distinguished from these, they have been too indefinitely denominated + instinctive, or automatic. I have been compelled, therefore, to adopt some + new designation for them, and I shall now give the reasons for my choice + of that which is given in the title of this paper—'Reflex + Functions.' + </p> + <p> + "This property is characterized by being EXCITED in its action and REFLEX + in its course: in every instance in which it is exerted an impression made + upon the extremities of certain nerves is conveyed to the medulla + oblongata or the medulla spinalis, and is reflected along the nerves to + parts adjacent to, or remote from, that which has received the impression. + </p> + <p> + "It is by this reflex character that the function to which I have alluded + is to be distinguished from every other. There are, in the animal economy, + four modes of muscular action, of muscular contraction. The first is that + designated VOLUNTARY: volition, originated in the cerebrum and spontaneous + in its acts, extends its influence along the spinal marrow and the motor + nerves in a DIRECT LINE to the voluntary muscles. The SECOND is that of + RESPIRATION: like volition, the motive influence in respiration passes in + a DIRECT LINE from one point of the nervous system to certain muscles; but + as voluntary motion seems to originate in the cerebrum, so the respiratory + motions originate in the medulla oblongata: like the voluntary motions, + the motions of respirations are spontaneous; they continue, at least, + after the eighth pair of nerves have been divided. The THIRD kind of + muscular action in the animal economy is that termed involuntary: it + depends upon the principle of irritability and requires the IMMEDIATE + application of a stimulus to the nervo-muscular fibre itself. These three + kinds of muscular motion are well known to physiologists; and I believe + they are all which have been hitherto pointed out. There is, however, a + FOURTH, which subsists, in part, after the voluntary and respiratory + motions have ceased, by the removal of the cerebrum and medulla oblongata, + and which is attached to the medulla spinalis, ceasing itself when this is + removed, and leaving the irritability undiminished. In this kind of + muscular motion the motive influence does not originate in any central + part of the nervous system, but from a distance from that centre; it is + neither spontaneous in its action nor direct in its course; it is, on the + contrary, EXCITED by the application of appropriate stimuli, which are + not, however, applied immediately to the muscular or nervo-muscular fibre, + but to certain membraneous parts, whence the impression is carried through + the medulla, REFLECTED and reconducted to the part impressed, or conducted + to a part remote from it in which muscular contraction is effected. + </p> + <p> + "The first three modes of muscular action are known only by actual + movements of muscular contractions. But the reflex function exists as a + continuous muscular action, as a power presiding over organs not actually + in a state of motion, preserving in some, as the glottis, an open, in + others, as the sphincters, a closed form, and in the limbs a due degree of + equilibrium or balanced muscular action—a function not, I think, + hitherto recognized by physiologists. + </p> + <p> + "The three kinds of muscular motion hitherto known may be distinguished in + another way. The muscles of voluntary motion and of respiration may be + excited by stimulating the nerves which supply them, in any part of their + course, whether at their source as a part of the medulla oblongata or the + medulla spinalis or exterior to the spinal canal: the muscles of + involuntary motion are chiefly excited by the actual contact of stimuli. + In the case of the reflex function alone the muscles are excited by a + stimulus acting mediately and indirectly in a curved and reflex course, + along superficial subcutaneous or submucous nerves proceeding from the + medulla. The first three of these causes of muscular motion may act on + detached limbs or muscles. The last requires the connection with the + medulla to be preserved entire. + </p> + <p> + "All the kinds of muscular motion may be unduly excited, but the reflex + function is peculiar in being excitable in two modes of action, not + previously subsisting in the animal economy, as in the case of sneezing, + coughing, vomiting, etc. The reflex function also admits of being + permanently diminished or augmented and of taking on some other morbid + forms, of which I shall treat hereafter. + </p> + <p> + "Before I proceed to the details of the experiments upon which this + disposition rests, it may be well to point out several instances in + illustration of the various sources of and the modes of muscular action + which have been enumerated. None can be more familiar than the act of + swallowing. Yet how complicated is the act! The apprehension of the food + by the teeth and tongue, etc., is voluntary, and cannot, therefore, take + place in an animal from which the cerebrum is removed. The transition of + food over the glottis and along the middle and lower part of the pharynx + depends upon the reflex action: it can take place in animals from which + the cerebrum has been removed or the ninth pair of nerves divided; but it + requires the connection with the medulla oblongata to be preserved + entirely; and the actual contact of some substance which may act as a + stimulus: it is attended by the accurate closure of the glottis and by the + contraction of the pharynx. The completion of the act of deglutition is + dependent upon the stimulus immediately impressed upon the muscular fibre + of the oesophagus, and is the result of excited irritability. + </p> + <p> + "However plain these observations may have made the fact that there is a + function of the nervous muscular system distinct from sensation, from the + voluntary and respiratory motions, and from irritability, it is right, in + every such inquiry as the present, that the statements and reasonings + should be made with the experiment, as it were, actually before us. It has + already been remarked that the voluntary and respiratory motions are + spontaneous, not necessarily requiring the agency of a stimulus. If, then, + an animal can be placed in such circumstances that such motions will + certainly not take place, the power of moving remaining, it may be + concluded that volition and the motive influence of respiration are + annihilated. Now this is effected by removing the cerebrum and the medulla + oblongata. These facts are fully proved by the experiments of Legallois + and M. Flourens, and by several which I proceed to detail, for the sake of + the opportunity afforded by doing so of stating the arguments most + clearly. + </p> + <p> + "I divided the spinal marrow of a very lively snake between the second and + third vertebrae. The movements of the animal were immediately before + extremely vigorous and unintermitted. From the moment of the division of + the spinal marrow it lay perfectly tranquil and motionless, with the + exception of occasional gaspings and slight movements of the head. It + became quite evident that this state of quiescence would continue + indefinitely were the animal secured from all external impressions. + </p> + <p> + "Being now stimulated, the body began to move with great activity, and + continued to do so for a considerable time, each change of position or + situation bringing some fresh part of the surface of the animal into + contact with the table or other objects and renewing the application of + stimulants. + </p> + <p> + "At length the animal became again quiescent; and being carefully + protected from all external impressions it moved no more, but died in the + precise position and form which it had last assumed. + </p> + <p> + "It requires a little manoeuvre to perform this experiment successfully: + the motions of the animal must be watched and slowly and cautiously + arrested by opposing some soft substance, as a glove or cotton wool; they + are by this means gradually lulled into quiescence. The slightest touch + with a hard substance, the slightest stimulus, will, on the other hand, + renew the movements on the animal in an active form. But that this + phenomenon does not depend upon sensation is further fully proved by the + facts that the position last assumed, and the stimuli, may be such as + would be attended by extreme or continued pain, if the sensibility were + undestroyed: in one case the animal remained partially suspended over the + acute edge of the table; in others the infliction of punctures and the + application of a lighted taper did not prevent the animal, still possessed + of active powers of motion, from passing into a state of complete and + permanent quiescence." + </p> + <p> + In summing up this long paper Hall concludes with this sentence: "The + reflex function appears in a word to be the COMPLEMENT of the functions of + the nervous system hitherto known."(2) + </p> + <p> + All these considerations as to nerve currents and nerve tracts becoming + stock knowledge of science, it was natural that interest should become + stimulated as to the exact character of these nerve tracts in themselves, + and all the more natural in that the perfected microscope was just now + claiming all fields for its own. A troop of observers soon entered upon + the study of the nerves, and the leader here, as in so many other lines of + microscopical research, was no other than Theodor Schwann. Through his + efforts, and with the invaluable aid of such other workers as Remak, + Purkinje, Henle, Muller, and the rest, all the mystery as to the general + characteristics of nerve tracts was cleared away. It came to be known that + in its essentials a nerve tract is a tenuous fibre or thread of protoplasm + stretching between two terminal points in the organism, one of such + termini being usually a cell of the brain or spinal cord, the other a + distribution-point at or near the periphery—for example, in a muscle + or in the skin. Such a fibril may have about it a protective covering, + which is known as the sheath of Schwann; but the fibril itself is the + essential nerve tract; and in many cases, as Remak presently discovered, + the sheath is dispensed with, particularly in case of the nerves of the + so-called sympathetic system. + </p> + <p> + This sympathetic system of ganglia and nerves, by-the-bye, had long been a + puzzle to the physiologists. Its ganglia, the seeming centre of the + system, usually minute in size and never very large, are found everywhere + through the organism, but in particular are gathered into a long double + chain which lies within the body cavity, outside the spinal column, and + represents the sole nervous system of the non-vertebrated organisms. + Fibrils from these ganglia were seen to join the cranial and spinal nerve + fibrils and to accompany them everywhere, but what special function they + subserved was long a mere matter of conjecture and led to many absurd + speculations. Fact was not substituted for conjecture until about the year + 1851, when the great Frenchman Claude Bernard conclusively proved that at + least one chief function of the sympathetic fibrils is to cause + contraction of the walls of the arterioles of the system, thus regulating + the blood-supply of any given part. Ten years earlier Henle had + demonstrated the existence of annular bands of muscle fibres in the + arterioles, hitherto a much-mooted question, and several tentative + explanations of the action of these fibres had been made, particularly by + the brothers Weber, by Stilling, who, as early as 1840, had ventured to + speak of "vaso-motor" nerves, and by Schiff, who was hard upon the same + track at the time of Bernard's discovery. But a clear light was not thrown + on the subject until Bernard's experiments were made in 1851. The + experiments were soon after confirmed and extended by Brown-Sequard, + Waller, Budge, and numerous others, and henceforth physiologists felt that + they understood how the blood-supply of any given part is regulated by the + nervous system. + </p> + <p> + In reality, however, they had learned only half the story, as Bernard + himself proved only a few years later by opening up a new and quite + unsuspected chapter. While experimenting in 1858 he discovered that there + are certain nerves supplying the heart which, if stimulated, cause that + organ to relax and cease beating. As the heart is essentially nothing more + than an aggregation of muscles, this phenomenon was utterly puzzling and + without precedent in the experience of physiologists. An impulse + travelling along a motor nerve had been supposed to be able to cause a + muscular contraction and to do nothing else; yet here such an impulse had + exactly the opposite effect. The only tenable explanation seemed to be + that this particular impulse must arrest or inhibit the action of the + impulses that ordinarily cause the heart muscles to contract. But the idea + of such inhibition of one impulse by another was utterly novel and at + first difficult to comprehend. Gradually, however, the idea took its place + in the current knowledge of nerve physiology, and in time it came to be + understood that what happens in the case of the heart nerve-supply is only + a particular case under a very general, indeed universal, form of nervous + action. Growing out of Bernard's initial discovery came the final + understanding that the entire nervous system is a mechanism of centres + subordinate and centres superior, the action of the one of which may be + counteracted and annulled in effect by the action of the other. This + applies not merely to such physical processes as heart-beats and arterial + contraction and relaxing, but to the most intricate functionings which + have their counterpart in psychical processes as well. Thus the + observation of the inhibition of the heart's action by a nervous impulse + furnished the point of departure for studies that led to a better + understanding of the modus operandi of the mind's activities than had ever + previously been attained by the most subtle of psychologists. + </p> + <p> + PSYCHO-PHYSICS + </p> + <p> + The work of the nerve physiologists had thus an important bearing on + questions of the mind. But there was another company of workers of this + period who made an even more direct assault upon the "citadel of thought." + A remarkable school of workers had been developed in Germany, the leaders + being men who, having more or less of innate metaphysical bias as a + national birthright, had also the instincts of the empirical scientist, + and whose educational equipment included a profound knowledge not alone of + physiology and psychology, but of physics and mathematics as well. These + men undertook the novel task of interrogating the relations of body and + mind from the standpoint of physics. They sought to apply the vernier and + the balance, as far as might be, to the intangible processes of mind. + </p> + <p> + The movement had its precursory stages in the early part of the century, + notably in the mathematical psychology of Herbart, but its first definite + output to attract general attention came from the master-hand of Hermann + Helmholtz in 1851. It consisted of the accurate measurement of the speed + of transit of a nervous impulse along a nerve tract. To make such + measurement had been regarded as impossible, it being supposed that the + flight of the nervous impulse was practically instantaneous. But Helmholtz + readily demonstrated the contrary, showing that the nerve cord is a + relatively sluggish message-bearer. According to his experiments, first + performed upon the frog, the nervous "current" travels less than one + hundred feet per second. Other experiments performed soon afterwards by + Helmholtz himself, and by various followers, chief among whom was Du + Bois-Reymond, modified somewhat the exact figures at first obtained, but + did not change the general bearings of the early results. Thus the nervous + impulse was shown to be something far different, as regards speed of + transit, at any rate, from the electric current to which it had been so + often likened. An electric current would flash halfway round the globe + while a nervous impulse could travel the length of the human body—from + a man's foot to his brain. + </p> + <p> + The tendency to bridge the gulf that hitherto had separated the physical + from the psychical world was further evidenced in the following decade by + Helmholtz's remarkable but highly technical study of the sensations of + sound and of color in connection with their physical causes, in the course + of which he revived the doctrine of color vision which that other great + physiologist and physicist, Thomas Young, had advanced half a century + before. The same tendency was further evidenced by the appearance, in + 1852, of Dr. Hermann Lotze's famous Medizinische Psychologie, oder + Physiologie der Seele, with its challenge of the old myth of a "vital + force." But the most definite expression of the new movement was + signalized in 1860, when Gustav Fechner published his classical work + called Psychophysik. That title introduced a new word into the vocabulary + of science. Fechner explained it by saying, "I mean by psychophysics an + exact theory of the relation between spirit and body, and, in a general + way, between the physical and the psychic worlds." The title became famous + and the brunt of many a controversy. So also did another phrase which + Fechner introduced in the course of his book—the phrase + "physiological psychology." In making that happy collocation of words + Fechner virtually christened a new science. + </p> + <p> + FECHNER EXPOUNDS WEBER'S LAW + </p> + <p> + The chief purport of this classical book of the German psycho-physiologist + was the elaboration and explication of experiments based on a method + introduced more than twenty years earlier by his countryman E. H. Weber, + but which hitherto had failed to attract the attention it deserved. The + method consisted of the measurement and analysis of the definite relation + existing between external stimuli of varying degrees of intensity (various + sounds, for example) and the mental states they induce. Weber's + experiments grew out of the familiar observation that the nicety of our + discriminations of various sounds, weights, or visual images depends upon + the magnitude of each particular cause of a sensation in its relation with + other similar causes. Thus, for example, we cannot see the stars in the + daytime, though they shine as brightly then as at night. Again, we seldom + notice the ticking of a clock in the daytime, though it may become almost + painfully audible in the silence of the night. Yet again, the difference + between an ounce weight and a two-ounce weight is clearly enough + appreciable when we lift the two, but one cannot discriminate in the same + way between a five-pound weight and a weight of one ounce over five + pounds. + </p> + <p> + This last example, and similar ones for the other senses, gave Weber the + clew to his novel experiments. Reflection upon every-day experiences made + it clear to him that whenever we consider two visual sensations, or two + auditory sensations, or two sensations of weight, in comparison one with + another, there is always a limit to the keenness of our discrimination, + and that this degree of keenness varies, as in the case of the weights + just cited, with the magnitude of the exciting cause. + </p> + <p> + Weber determined to see whether these common experiences could be brought + within the pale of a general law. His method consisted of making long + series of experiments aimed at the determination, in each case, of what + came to be spoken of as the least observable difference between the + stimuli. Thus if one holds an ounce weight in each hand, and has tiny + weights added to one of them, grain by grain, one does not at first + perceive a difference; but presently, on the addition of a certain grain, + he does become aware of the difference. Noting now how many grains have + been added to produce this effect, we have the weight which represents the + least appreciable difference when the standard is one ounce. + </p> + <p> + Now repeat the experiment, but let the weights be each of five pounds. + Clearly in this case we shall be obliged to add not grains, but drachms, + before a difference between the two heavy weights is perceived. But + whatever the exact amount added, that amount represents the stimulus + producing a just-perceivable sensation of difference when the standard is + five pounds. And so on for indefinite series of weights of varying + magnitudes. Now came Weber's curious discovery. Not only did he find that + in repeated experiments with the same pair of weights the measure of + "just-{p}erceivable difference" remained approximately fixed, but he + found, further, that a remarkable fixed relation exists between the + stimuli of different magnitude. If, for example, he had found it + necessary, in the case of the ounce weights, to add one-fiftieth of an + ounce to the one before a difference was detected, he found also, in the + case of the five-pound weights, that one-fiftieth of five pounds must be + added before producing the same result. And so of all other weights; the + amount added to produce the stimulus of "least-appreciable difference" + always bore the same mathematical relation to the magnitude of the weight + used, be that magnitude great or small. + </p> + <p> + Weber found that the same thing holds good for the stimuli of the + sensations of sight and of hearing, the differential stimulus bearing + always a fixed ratio to the total magnitude of the stimuli. Here, then, + was the law he had sought. + </p> + <p> + Weber's results were definite enough and striking enough, yet they failed + to attract any considerable measure of attention until they were revived + and extended by Fechner and brought before the world in the famous work on + psycho-physics. Then they precipitated a veritable melee. Fechner had not + alone verified the earlier results (with certain limitations not essential + to the present consideration), but had invented new methods of making + similar tests, and had reduced the whole question to mathematical + treatment. He pronounced Weber's discovery the fundamental law of + psycho-physics. In honor of the discoverer, he christened it Weber's Law. + He clothed the law in words and in mathematical formulae, and, so to say, + launched it full tilt at the heads of the psychological world. It made a + fine commotion, be assured, for it was the first widely heralded bulletin + of the new psychology in its march upon the strongholds of the + time-honored metaphysics. The accomplishments of the microscopists and the + nerve physiologists had been but preliminary—mere border skirmishes + of uncertain import. But here was proof that the iconoclastic movement + meant to invade the very heart of the sacred territory of mind—a + territory from which tangible objective fact had been supposed to be + forever barred. + </p> + <p> + PHYSIOLOGICAL PSYCHOLOGY + </p> + <p> + Hardly had the alarm been sounded, however, before a new movement was + made. While Fechner's book was fresh from the press, steps were being + taken to extend the methods of the physicist in yet another way to the + intimate processes of the mind. As Helmholtz had shown the rate of nervous + impulsion along the nerve tract to be measurable, it was now sought to + measure also the time required for the central nervous mechanism to + perform its work of receiving a message and sending out a response. This + was coming down to the very threshold of mind. The attempt was first made + by Professor Donders in 1861, but definitive results were only obtained + after many years of experiment on the part of a host of observers. The + chief of these, and the man who has stood in the forefront of the new + movement and has been its recognized leader throughout the remainder of + the century, is Dr. Wilhelm Wundt, of Leipzig. + </p> + <p> + The task was not easy, but, in the long run, it was accomplished. Not + alone was it shown that the nerve centre requires a measurable time for + its operations, but much was learned as to conditions that modify this + time. Thus it was found that different persons vary in the rate of their + central nervous activity—which explained the "personal equation" + that the astronomer Bessel had noted a half-century before. It was found, + too, that the rate of activity varies also for the same person under + different conditions, becoming retarded, for example, under influence of + fatigue, or in case of certain diseases of the brain. All details aside, + the essential fact emerges, as an experimental demonstration, that the + intellectual processes—sensation, apperception, volition—are + linked irrevocably with the activities of the central nervous tissues, and + that these activities, like all other physical processes, have a time + element. To that old school of psychologists, who scarcely cared more for + the human head than for the heels—being interested only in the mind—such + a linking of mind and body as was thus demonstrated was naturally + disquieting. But whatever the inferences, there was no escaping the facts. + </p> + <p> + Of course this new movement has not been confined to Germany. Indeed, it + had long had exponents elsewhere. Thus in England, a full century earlier, + Dr. Hartley had championed the theory of the close and indissoluble + dependence of the mind upon the brain, and formulated a famous vibration + theory of association that still merits careful consideration. Then, too, + in France, at the beginning of the century, there was Dr. Cabanis with his + tangible, if crudely phrased, doctrine that the brain digests impressions + and secretes thought as the stomach digests food and the liver secretes + bile. Moreover, Herbert Spencer's Principles of Psychology, with its + avowed co-ordination of mind and body and its vitalizing theory of + evolution, appeared in 1855, half a decade before the work of Fechner. But + these influences, though of vast educational value, were theoretical + rather than demonstrative, and the fact remains that the experimental work + which first attempted to gauge mental operations by physical principles + was mainly done in Germany. Wundt's Physiological Psychology, with its + full preliminary descriptions of the anatomy of the nervous system, gave + tangible expression to the growth of the new movement in 1874; and four + years later, with the opening of his laboratory of physiological + psychology at the University of Leipzig, the new psychology may be said to + have gained a permanent foothold and to have forced itself into official + recognition. From then on its conquest of the world was but a matter of + time. + </p> + <p> + It should be noted, however, that there is one other method of strictly + experimental examination of the mental field, latterly much in vogue, + which had a different origin. This is the scientific investigation of the + phenomena of hypnotism. This subject was rescued from the hands of + charlatans, rechristened, and subjected to accurate investigation by Dr. + James Braid, of Manchester, as early as 1841. But his results, after + attracting momentary attention, fell from view, and, despite desultory + efforts, the subject was not again accorded a general hearing from the + scientific world until 1878, when Dr. Charcot took it up at the + Salpetriere, in Paris, followed soon afterwards by Dr. Rudolf Heidenhain, + of Breslau, and a host of other experimenters. The value of the method in + the study of mental states was soon apparent. Most of Braid's experiments + were repeated, and in the main his results were confirmed. His explanation + of hypnotism, or artificial somnambulism, as a self-induced state, + independent of any occult or supersensible influence, soon gained general + credence. His belief that the initial stages are due to fatigue of nervous + centres, usually from excessive stimulation, has not been supplanted, + though supplemented by notions growing out of the new knowledge as to + subconscious mentality in general, and the inhibitory influence of one + centre over another in the central nervous mechanism. + </p> + <p> + THE BRAIN AS THE ORGAN OF MIND + </p> + <p> + These studies of the psychologists and pathologists bring the relations of + mind and body into sharp relief. But even more definite in this regard was + the work of the brain physiologists. Chief of these, during the middle + period of the century, was the man who is sometimes spoken of as the + "father of brain physiology," Marie Jean Pierre Flourens, of the Jardin + des Plantes of Paris, the pupil and worthy successor of Magendie. His + experiments in nerve physiology were begun in the first quarter of the + century, but his local experiments upon the brain itself were not + culminated until about 1842. At this time the old dispute over phrenology + had broken out afresh, and the studies of Flourens were aimed, in part at + least, at the strictly scientific investigation of this troublesome topic. + </p> + <p> + In the course of these studies Flourens discovered that in the medulla + oblongata, the part of the brain which connects that organ with the spinal + cord, there is a centre of minute size which cannot be injured in the + least without causing the instant death of the animal operated upon. It + may be added that it is this spot which is reached by the needle of the + garroter in Spanish executions, and that the same centre also is destroyed + when a criminal is "successfully" hanged, this time by the forced + intrusion of a process of the second cervical vertebra. Flourens named + this spot the "vital knot." Its extreme importance, as is now understood, + is due to the fact that it is the centre of nerves that supply the heart; + but this simple explanation, annulling the conception of a specific "life + centre," was not at once apparent. + </p> + <p> + Other experiments of Flourens seemed to show that the cerebellum is the + seat of the centres that co-ordinate muscular activities, and that the + higher intellectual faculties are relegated to the cerebrum. But beyond + this, as regards localization, experiment faltered. Negative results, as + regards specific faculties, were obtained from all localized irritations + of the cerebrum, and Flourens was forced to conclude that the cerebral + lobe, while being undoubtedly the seat of higher intellection, performs + its functions with its entire structure. This conclusion, which + incidentally gave a quietus to phrenology, was accepted generally, and + became the stock doctrine of cerebral physiology for a generation. + </p> + <p> + It will be seen, however, that these studies of Flourens had a double + bearing. They denied localization of cerebral functions, but they + demonstrated the localization of certain nervous processes in other + portions of the brain. On the whole, then, they spoke positively for the + principle of localization of function in the brain, for which a certain + number of students contended; while their evidence against cerebral + localization was only negative. There was here and there an observer who + felt that this negative testimony was not conclusive. In particular, the + German anatomist Meynert, who had studied the disposition of nerve tracts + in the cerebrum, was led to believe that the anterior portions of the + cerebrum must have motor functions in preponderance; the posterior + positions, sensory functions. Somewhat similar conclusions were reached + also by Dr. Hughlings-Jackson, in England, from his studies of epilepsy. + But no positive evidence was forthcoming until 1861, when Dr. Paul Broca + brought before the Academy of Medicine in Paris a case of brain lesion + which he regarded as having most important bearings on the question of + cerebral localization. + </p> + <p> + The case was that of a patient at the Bicetre, who for twenty years had + been deprived of the power of speech, seemingly through loss of memory of + words. In 1861 this patient died, and an autopsy revealed that a certain + convolution of the left frontal lobe of his cerebrum had been totally + destroyed by disease, the remainder of his brain being intact. Broca felt + that this observation pointed strongly to a localization of the memory of + words in a definite area of the brain. Moreover, it transpired that the + case was not without precedent. As long ago as 1825 Dr. Boillard had been + led, through pathological studies, to locate definitely a centre for the + articulation of words in the frontal lobe, and here and there other + observers had made tentatives in the same direction. Boillard had even + followed the matter up with pertinacity, but the world was not ready to + listen to him. Now, however, in the half-decade that followed Broca's + announcements, interest rose to fever-beat, and through the efforts of + Broca, Boillard, and numerous others it was proved that a veritable centre + having a strange domination over the memory of articulate words has its + seat in the third convolution of the frontal lobe of the cerebrum, usually + in the left hemisphere. That part of the brain has since been known to the + English-speaking world as the convolution of Broca, a name which, + strangely enough, the discoverer's compatriots have been slow to accept. + </p> + <p> + This discovery very naturally reopened the entire subject of brain + localization. It was but a short step to the inference that there must be + other definite centres worth the seeking, and various observers set about + searching for them. In 1867 a clew was gained by Eckhard, who, repeating a + forgotten experiment by Haller and Zinn of the previous century, removed + portions of the brain cortex of animals, with the result of producing + convulsions. But the really vital departure was made in 1870 by the German + investigators Fritsch and Hitzig, who, by stimulating definite areas of + the cortex of animals with a galvanic current, produced contraction of + definite sets of muscles of the opposite side of the body. These most + important experiments, received at first with incredulity, were repeated + and extended in 1873 by Dr. David Ferrier, of London, and soon afterwards + by a small army of independent workers everywhere, prominent among whom + were Franck and Pitres in France, Munck and Goltz in Germany, and Horsley + and Schafer in England. The detailed results, naturally enough, were not + at first all in harmony. Some observers, as Goltz, even denied the + validity of the conclusions in toto. But a consensus of opinion, based on + multitudes of experiments, soon placed the broad general facts for which + Fritsch and Hitzig contended beyond controversy. It was found, indeed, + that the cerebral centres of motor activities have not quite the finality + at first ascribed to them by some observers, since it may often happen + that after the destruction of a centre, with attending loss of function, + there may be a gradual restoration of the lost function, proving that + other centres have acquired the capacity to take the place of the one + destroyed. There are limits to this capacity for substitution, however, + and with this qualification the definiteness of the localization of motor + functions in the cerebral cortex has become an accepted part of brain + physiology. + </p> + <p> + Nor is such localization confined to motor centres. Later experiments, + particularly of Ferrier and of Munck, proved that the centres of vision + are equally restricted in their location, this time in the posterior lobes + of the brain, and that hearing has likewise its local habitation. Indeed, + there is every reason to believe that each form of primary sensation is + based on impressions which mainly come to a definitely localized goal in + the brain. But all this, be it understood, has no reference to the higher + forms of intellection. All experiment has proved futile to localize these + functions, except indeed to the extent of corroborating the familiar fact + of their dependence upon the brain, and, somewhat problematically, upon + the anterior lobes of the cerebrum in particular. But this is precisely + what should be expected, for the clearer insight into the nature of mental + processes makes it plain that in the main these alleged "faculties" are + not in themselves localized. Thus, for example, the "faculty" of language + is associated irrevocably with centres of vision, of hearing, and of + muscular activity, to go no further, and only becomes possible through the + association of these widely separated centres. The destruction of Broca's + centre, as was early discovered, does not altogether deprive a patient of + his knowledge of language. He may be totally unable to speak (though as to + this there are all degrees of variation), and yet may comprehend what is + said to him, and be able to read, think, and even write correctly. Thus it + appears that Broca's centre is peculiarly bound up with the capacity for + articulate speech, but is far enough from being the seat of the faculty of + language in its entirety. + </p> + <p> + In a similar way, most of the supposed isolated "faculties" of higher + intellection appear, upon clearer analysis, as complex aggregations of + primary sensations, and hence necessarily dependent upon numerous and + scattered centres. Some "faculties," as memory and volition, may be said + in a sense to be primordial endowments of every nerve cell—even of + every body cell. Indeed, an ultimate analysis relegates all intellection, + in its primordial adumbrations, to every particle of living matter. But + such refinements of analysis, after all, cannot hide the fact that certain + forms of higher intellection involve a pretty definite collocation and + elaboration of special sensations. Such specialization, indeed, seems a + necessary accompaniment of mental evolution. That every such specialized + function has its localized centres of co-ordination, of some such + significance as the demonstrated centres of articulate speech, can hardly + be in doubt—though this, be it understood, is an induction, not as + yet a demonstration. In other words, there is every reason to believe that + numerous "centres," in this restricted sense, exist in the brain that have + as yet eluded the investigator. Indeed, the current conception regards the + entire cerebral cortex as chiefly composed of centres of ultimate + co-ordination of impressions, which in their cruder form are received by + more primitive nervous tissues—the basal ganglia, the cerebellum and + medulla, and the spinal cord. + </p> + <p> + This, of course, is equivalent to postulating the cerebral cortex as the + exclusive seat of higher intellection. This proposition, however, to which + a safe induction seems to lead, is far afield from the substantiation of + the old conception of brain localization, which was based on faulty + psychology and equally faulty inductions from few premises. The details of + Gall's system, as propounded by generations of his mostly unworthy + followers, lie quite beyond the pale of scientific discussion. Yet, as I + have said, a germ of truth was there—the idea of specialization of + cerebral functions—and modern investigators have rescued that + central conception from the phrenological rubbish heap in which its + discoverer unfortunately left it buried. + </p> + <p> + THE MINUTE STRUCTURE OF THE BRAIN + </p> + <p> + The common ground of all these various lines of investigations of + pathologist, anatomist, physiologist, physicist, and psychologist is, + clearly, the central nervous system—the spinal cord and the brain. + The importance of these structures as the foci of nervous and mental + activities has been recognized more and more with each new accretion of + knowledge, and the efforts to fathom the secrets of their intimate + structure has been unceasing. For the earlier students, only the crude + methods of gross dissections and microscopical inspection were available. + These could reveal something, but of course the inner secrets were for the + keener insight of the microscopist alone. And even for him the task of + investigation was far from facile, for the central nervous tissues are the + most delicate and fragile, and on many accounts the most difficult of + manipulation of any in the body. + </p> + <p> + Special methods, therefore, were needed for this essay, and brain + histology has progressed by fitful impulses, each forward jet marking the + introduction of some ingenious improvement of mechanical technique, which + placed a new weapon in the hands of the investigators. + </p> + <p> + The very beginning was made in 1824 by Rolando, who first thought of + cutting chemically hardened pieces of brain tissues into thin sections for + microscopical examination—the basal structure upon which almost all + the later advances have been conducted. Muller presently discovered that + bichromate of potassium in solution makes the best of fluids for the + preliminary preservation and hardening of the tissues. Stilling, in 1842, + perfected the method by introducing the custom of cutting a series of + consecutive sections of the same tissue, in order to trace nerve tracts + and establish spacial relations. Then from time to time mechanical + ingenuity added fresh details of improvement. It was found that pieces of + hardened tissue of extreme delicacy can be made better subject to + manipulation by being impregnated with collodion or celloidine and + embedded in paraffine. Latterly it has become usual to cut sections also + from fresh tissues, unchanged by chemicals, by freezing them suddenly with + vaporized ether or, better, carbonic acid. By these methods, and with the + aid of perfected microtomes, the worker of recent periods avails himself + of sections of brain tissues of a tenuousness which the early + investigators could not approach. + </p> + <p> + But more important even than the cutting of thin sections is the process + of making the different parts of the section visible, one tissue + differentiated from another. The thin section, as the early workers + examined it, was practically colorless, and even the crudest details of + its structure were made out with extreme difficulty. Remak did, indeed, + manage to discover that the brain tissue is cellular, as early as 1833, + and Ehrenberg in the same year saw that it is also fibrillar, but beyond + this no great advance was made until 1858, when a sudden impulse was + received from a new process introduced by Gerlach. The process itself was + most simple, consisting essentially of nothing more than the treatment of + a microscopical section with a solution of carmine. But the result was + wonderful, for when such a section was placed under the lens it no longer + appeared homogeneous. Sprinkled through its substance were seen irregular + bodies that had taken on a beautiful color, while the matrix in which they + were embedded remained unstained. In a word, the central nerve cell had + sprung suddenly into clear view. + </p> + <p> + A most interesting body it proved, this nerve cell, or ganglion cell, as + it came to be called. It was seen to be exceedingly minute in size, + requiring high powers of the microscope to make it visible. It exists in + almost infinite numbers, not, however, scattered at random through the + brain and spinal cord. On the contrary, it is confined to those portions + of the central nervous masses which to the naked eye appear gray in color, + being altogether wanting in the white substance which makes up the chief + mass of the brain. Even in the gray matter, though sometimes thickly + distributed, the ganglion cells are never in actual contact one with + another; they always lie embedded in intercellular tissues, which came to + be known, following Virchow, as the neuroglia. + </p> + <p> + Each ganglion cell was seen to be irregular in contour, and to have + jutting out from it two sets of minute fibres, one set relatively short, + indefinitely numerous, and branching in every direction; the other set + limited in number, sometimes even single, and starting out directly from + the cell as if bent on a longer journey. The numerous filaments came to be + known as protoplasmic processes; the other fibre was named, after its + discoverer, the axis cylinder of Deiters. It was a natural inference, + though not clearly demonstrable in the sections, that these filamentous + processes are the connecting links between the different nerve cells and + also the channels of communication between nerve cells and the periphery + of the body. The white substance of brain and cord, apparently, is made up + of such connecting fibres, thus bringing the different ganglion cells + everywhere into communication one with another. + </p> + <p> + In the attempt to trace the connecting nerve tracts through this white + substance by either macroscopical or microscopical methods, most important + aid is given by a method originated by Waller in 1852. Earlier than that, + in 1839, Nasse had discovered that a severed nerve cord degenerates in its + peripheral portions. Waller discovered that every nerve fibre, sensory or + motor, has a nerve cell to or from which it leads, which dominates its + nutrition, so that it can only retain its vitality while its connection + with that cell is intact. Such cells he named trophic centres. Certain + cells of the anterior part of the spinal cord, for example, are the + trophic centres of the spinal motor nerves. Other trophic centres, + governing nerve tracts in the spinal cord itself, are in the various + regions of the brain. It occurred to Waller that by destroying such + centres, or by severing the connection at various regions between a + nervous tract and its trophic centre, sharply defined tracts could be made + to degenerate, and their location could subsequently be accurately + defined, as the degenerated tissues take on a changed aspect, both to + macroscopical and microscopical observation. Recognition of this principle + thus gave the experimenter a new weapon of great efficiency in tracing + nervous connections. Moreover, the same principle has wide application in + case of the human subject in disease, such as the lesion of nerve tracts + or the destruction of centres by localized tumors, by embolisms, or by + traumatisms. + </p> + <p> + All these various methods of anatomical examination combine to make the + conclusion almost unavoidable that the central ganglion cells are the + veritable "centres" of nervous activity to which so many other lines of + research have pointed. The conclusion was strengthened by experiments of + the students of motor localization, which showed that the veritable + centres of their discovery lie, demonstrably, in the gray cortex of the + brain, not in the white matter. But the full proof came from pathology. At + the hands of a multitude of observers it was shown that in certain + well-known diseases of the spinal cord, with resulting paralysis, it is + the ganglion cells themselves that are found to be destroyed. Similarly, + in the case of sufferers from chronic insanities, with marked dementia, + the ganglion cells of the cortex of the brain are found to have undergone + degeneration. The brains of paretics in particular show such degeneration, + in striking correspondence with their mental decadence. The position of + the ganglion cell as the ultimate centre of nervous activities was thus + placed beyond dispute. + </p> + <p> + Meantime, general acceptance being given the histological scheme of + Gerlach, according to which the mass of the white substance of the brain + is a mesh-work of intercellular fibrils, a proximal idea seemed attainable + of the way in which the ganglionic activities are correlated, and, through + association, built up, so to speak, into the higher mental processes. Such + a conception accorded beautifully with the ideas of the associationists, + who had now become dominant in psychology. But one standing puzzle + attended this otherwise satisfactory correlation of anatomical + observations and psychic analyses. It was this: Since, according to the + histologist, the intercellular fibres, along which impulses are conveyed, + connect each brain cell, directly or indirectly, with every other brain + cell in an endless mesh-work, how is it possible that various sets of + cells may at times be shut off from one another? Such isolation must take + place, for all normal ideation depends for its integrity quite as much + upon the shutting-out of the great mass of associations as upon the + inclusion of certain other associations. For example, a student in solving + a mathematical problem must for the moment become quite oblivious to the + special associations that have to do with geography, natural history, and + the like. But does histology give any clew to the way in which such + isolation may be effected? + </p> + <p> + Attempts were made to find an answer through consideration of the very + peculiar character of the blood-supply in the brain. Here, as nowhere + else, the terminal twigs of the arteries are arranged in closed systems, + not anastomosing freely with neighboring systems. Clearly, then, a + restricted area of the brain may, through the controlling influence of the + vasomotor nerves, be flushed with arterial blood while neighboring parts + remain relatively anaemic. And since vital activities unquestionably + depend in part upon the supply of arterial blood, this peculiar + arrangement of the vascular mechanism may very properly be supposed to aid + in the localized activities of the central nervous ganglia. But this + explanation left much to be desired—in particular when it is + recalled that all higher intellection must in all probability involve + multitudes of widely scattered centres. + </p> + <p> + No better explanation was forthcoming, however, until the year 1889, when + of a sudden the mystery was cleared away by a fresh discovery. Not long + before this the Italian histologist Dr. Camille Golgi had discovered a + method of impregnating hardened brain tissues with a solution of nitrate + of silver, with the result of staining the nerve cells and their processes + almost infinitely better than was possible by the methods of Gerlach, or + by any of the multiform methods that other workers had introduced. Now for + the first time it became possible to trace the cellular prolongations + definitely to their termini, for the finer fibrils had not been rendered + visible by any previous method of treatment. Golgi himself proved that the + set of fibrils known as protoplasmic prolongations terminate by free + extremities, and have no direct connection with any cell save the one from + which they spring. He showed also that the axis cylinders give off + multitudes of lateral branches not hitherto suspected. But here he paused, + missing the real import of the discovery of which he was hard on the + track. It remained for the Spanish histologist Dr. S. Ramon y Cajal to + follow up the investigation by means of an improved application of Golgi's + method of staining, and to demonstrate that the axis cylinders, together + with all their collateral branches, though sometimes extending to a great + distance, yet finally terminate, like the other cell prolongations, in + arborescent fibrils having free extremities. In a word, it was shown that + each central nerve cell, with its fibrillar offshoots, is an isolated + entity. Instead of being in physical connection with a multitude of other + nerve cells, it has no direct physical connection with any other nerve + cell whatever. + </p> + <p> + When Dr. Cajal announced his discovery, in 1889, his revolutionary claims + not unnaturally amazed the mass of histologists. There were some few of + them, however, who were not quite unprepared for the revelation; in + particular His, who had half suspected the independence of the cells, + because they seemed to develop from dissociated centres; and Forel, who + based a similar suspicion on the fact that he had never been able actually + to trace a fibre from one cell to another. These observers then came + readily to repeat Cajal's experiments. So also did the veteran histologist + Kolliker, and soon afterwards all the leaders everywhere. The result was a + practically unanimous confirmation of the Spanish histologist's claims, + and within a few months after his announcements the old theory of union of + nerve cells into an endless mesh-work was completely discarded, and the + theory of isolated nerve elements—the theory of neurons, as it came + to be called—was fully established in its place. + </p> + <p> + As to how these isolated nerve cells functionate, Dr. Cajal gave the clew + from the very first, and his explanation has met with universal approval. + </p> + <p> + In the modified view, the nerve cell retains its old position as the + storehouse of nervous energy. Each of the filaments jutting out from the + cell is held, as before, to be indeed a transmitter of impulses, but a + transmitter that operates intermittently, like a telephone wire that is + not always "connected," and, like that wire, the nerve fibril operates by + contact and not by continuity. Under proper stimulation the ends of the + fibrils reach out, come in contact with other end fibrils of other cells, + and conduct their destined impulse. Again they retract, and communication + ceases for the time between those particular cells. Meantime, by a + different arrangement of the various conductors, different sets of cells + are placed in communication, different associations of nervous impulses + induced, different trains of thought engendered. Each fibril when + retracted becomes a non-conductor, but when extended and in contact with + another fibril, or with the body of another cell, it conducts its message + as readily as a continuous filament could do—precisely as in the + case of an electric wire. + </p> + <p> + This conception, founded on a most tangible anatomical basis, enables us + to answer the question as to how ideas are isolated, and also, as Dr. + Cajal points out, throws new light on many other mental processes. One can + imagine, for example, by keeping in mind the flexible nerve prolongations, + how new trains of thought may be engendered through novel associations of + cells; how facility of thought or of action in certain directions is + acquired through the habitual making of certain nerve-cell connections; + how certain bits of knowledge may escape our memory and refuse to be found + for a time because of a temporary incapacity of the nerve cells to make + the proper connections, and so on indefinitely. + </p> + <p> + If one likens each nerve cell to a central telephone office, each of its + filamentous prolongations to a telephone wire, one can imagine a striking + analogy between the modus operandi of nervous processes and of the + telephone system. The utility of new connections at the central office, + the uselessness of the mechanism when the connections cannot be made, the + "wires in use" that retard your message, perhaps even the crossing of + wires, bringing you a jangle of sounds far different from what you desire—all + these and a multiplicity of other things that will suggest themselves to + every user of the telephone may be imagined as being almost ludicrously + paralleled in the operations of the nervous mechanism. And that parallel, + startling as it may seem, is not a mere futile imagining. It is sustained + and rendered plausible by a sound substratum of knowledge of the + anatomical conditions under which the central nervous mechanism exists, + and in default of which, as pathology demonstrates with no less certitude, + its functionings are futile to produce the normal manifestations of higher + intellection. + </p> + <p> + <a name="link2H_4_0011" id="link2H_4_0011"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + X. THE NEW SCIENCE OF ORIENTAL ARCHAEOLOGY + </h2> + <h3> + HOW THE "RIDDLE OF THE SPHINX" WAS READ + </h3> + <p> + Conspicuously placed in the great hall of Egyptian antiquities in the + British Museum is a wonderful piece of sculpture known as the Rosetta + Stone. I doubt if any other piece in the entire exhibit attracts so much + attention from the casual visitor as this slab of black basalt on its + telescope-like pedestal. The hall itself, despite its profusion of + strangely sculptured treasures, is never crowded, but before this stone + you may almost always find some one standing, gazing with more or less of + discernment at the strange characters that are graven neatly across its + upturned, glass-protected face. A glance at this graven surface suffices + to show that three sets of inscriptions are recorded there. The upper one, + occupying about one-fourth of the surface, is a pictured scroll, made up + of chains of those strange outlines of serpents, hawks, lions, and so on, + which are recognized, even by the least initiated, as hieroglyphics. The + middle inscription, made up of lines, angles, and half-pictures, one might + surmise to be a sort of abbreviated or short-hand hieroglyphic. The third + or lower inscription is Greek—obviously a thing of words. If the + screeds above be also made of words, only the elect have any way of + proving the fact. + </p> + <p> + Fortunately, however, even the least scholarly observer is left in no + doubt as to the real import of the thing he sees, for an obliging English + label tells us that these three inscriptions are renderings of the same + message, and that this message is a "decree of the priests of Memphis + conferring divine honors on Ptolemy V. (Epiphenes), King of Egypt, B.C. + 195." The label goes on to state that the upper inscription (of which, + unfortunately, only part of the last dozen lines or so remains, the slab + being broken) is in "the Egyptian language, in hieroglyphics, or writing + of the priests"; the second inscription "in the same language is in + Demotic, or the writing of the people"; and the third "the Greek language + and character." Following this is a brief biography of the Rosetta Stone + itself, as follows: "The stone was found by the French in 1798 among the + ruins of Fort Saint Julien, near the Rosetta mouth of the Nile. It passed + into the hands of the British by the treaty of Alexandria, and was + deposited in the British Museum in the year 1801." There is a whole volume + of history in that brief inscription—and a bitter sting thrown in, + if the reader chance to be a Frenchman. Yet the facts involved could + scarcely be suggested more modestly. They are recorded much more bluntly + in a graven inscription on the side of the stone, which reads: "Captured + in Egypt by the British Army, 1801." No Frenchman could read those words + without a veritable sinking of the heart. + </p> + <p> + The value of the Rosetta Stone depended on the fact that it gave promise, + even when casually inspected, of furnishing a key to the centuries-old + mystery of the hieroglyphics. For two thousand years the secret of these + strange markings had been forgotten. Nowhere in the world—quite as + little in Egypt as elsewhere—had any man the slightest clew to their + meaning; there were those who even doubted whether these droll picturings + really had any specific meaning, questioning whether they were not rather + vague symbols of esoteric religious import and nothing more. And it was + the Rosetta Stone that gave the answer to these doubters and restored to + the world a lost language and a forgotten literature. + </p> + <p> + The trustees of the museum recognized at once that the problem of the + Rosetta Stone was one on which the scientists of the world might well + exhaust their ingenuity, and promptly published to the world a carefully + lithographed copy of the entire inscription, so that foreign scholarship + had equal opportunity with the British to try at the riddle. It was an + Englishman, however, who first gained a clew to the solution. This was + none other than the extraordinary Dr. Thomas Young, the demonstrator of + the vibratory nature of light. + </p> + <p> + Young's specific discoveries were these: (1) That many of the pictures of + the hieroglyphics stand for the names of the objects actually delineated; + (2) that other pictures are sometimes only symbolic; (3) that plural + numbers are represented by repetition; (4) that numerals are represented + by dashes; (5) that hieroglyphics may read either from the right or from + the left, but always from the direction in which the animal and human + figures face; (6) that proper names are surrounded by a graven oval ring, + making what he called a cartouche; (7) that the cartouches of the + preserved portion of the Rosetta Stone stand for the name of Ptolemy + alone; (8) that the presence of a female figure after such cartouches in + other inscriptions always denotes the female sex; (9) that within the + cartouches the hieroglyphic symbols have a positively phonetic value, + either alphabetic or syllabic; and (10) that several different characters + may have the same phonetic value. + </p> + <p> + Just what these phonetic values are Young pointed out in the case of + fourteen characters representing nine sounds, six of which are accepted + to-day as correctly representing the letters to which he ascribed them, + and the three others as being correct regarding their essential or + consonant element. It is clear, therefore, that he was on the right track + thus far, and on the very verge of complete discovery. But, unfortunately, + he failed to take the next step, which would have been to realize that the + same phonetic values which were given to the alphabetic characters within + the cartouches were often ascribed to them also when used in the general + text of an inscription; in other words, that the use of an alphabet was + not confined to proper names. This was the great secret which Young missed + and which his French successor, Jean Francois Champollion, working on the + foundation that Young had laid, was enabled to ferret out. + </p> + <p> + Young's initial studies of the Rosetta Stone were made in 1814; his later + publication bore date of 1819. Champollion's first announcement of results + came in 1822; his second and more important one in 1824. By this time, + through study of the cartouches of other inscriptions, Champollion had + made out almost the complete alphabet, and the "riddle of the Sphinx" was + practically solved. He proved that the Egyptians had developed a + relatively complete alphabet (mostly neglecting the vowels, as early + Semitic alphabets did also) centuries before the Phoenicians were heard of + in history. What relation this alphabet bore to the Phoenician we shall + have occasion to ask in another connection; for the moment it suffices to + know that those strange pictures of the Egyptian scroll are really + letters. + </p> + <p> + Even this statement, however, must be in a measure modified. These + pictures are letters and something more. Some of them are purely + alphabetical in character and some are symbolic in another way. Some + characters represent syllables. Others stand sometimes as mere + representatives of sounds, and again, in a more extended sense, as + representations of things, such as all hieroglyphics doubtless were in the + beginning. In a word, this is an alphabet, but not a perfected alphabet, + such as modern nations are accustomed to; hence the enormous complications + and difficulties it presented to the early investigators. + </p> + <p> + Champollion did not live to clear up all these mysteries. His work was + taken up and extended by his pupil Rossellini, and in particular by Dr. + Richard Lepsius in Germany, followed by M. Bernouf, and by Samuel Birch of + the British Museum, and more recently by such well-known Egyptologists as + MM. Maspero and Mariette and Chabas, in France, Dr. Brugsch, in Germany, + and Dr. E. Wallis Budge, the present head of the Department of Oriental + Antiquities at the British Museum. But the task of later investigators has + been largely one of exhumation and translation of records rather than of + finding methods. + </p> + <p> + TREASURES FROM NINEVEH + </p> + <p> + The most casual wanderer in the British Museum can hardly fail to notice + two pairs of massive sculptures, in the one case winged bulls, in the + other winged lions, both human-headed, which guard the entrance to the + Egyptian hall, close to the Rosetta Stone. Each pair of these weird + creatures once guarded an entrance to the palace of a king in the famous + city of Nineveh. As one stands before them his mind is carried back over + some twenty-seven intervening centuries, to the days when the "Cedar of + Lebanon" was "fair in his greatness" and the scourge of Israel. + </p> + <p> + The very Sculptures before us, for example, were perhaps seen by Jonah + when he made that famous voyage to Nineveh some seven or eight hundred + years B.C. A little later the Babylonian and the Mede revolted against + Assyrian tyranny and descended upon the fair city of Nineveh, and almost + literally levelled it to the ground. But these great sculptures, among + other things, escaped destruction, and at once hidden and preserved by the + accumulating debris of the centuries, they stood there age after age, + their very existence quite forgotten. When Xenophon marched past their + site with the ill-starred expedition of the ten thousand, in the year 400 + B.C., he saw only a mound which seemed to mark the site of some ancient + ruin; but the Greek did not suspect that he looked upon the site of that + city which only two centuries before had been the mistress of the world. + </p> + <p> + So ephemeral is fame! And yet the moral scarcely holds in the sequel; for + we of to-day, in this new, undreamed-of Western world, behold these + mementos of Assyrian greatness fresh from their twenty-five hundred years + of entombment, and with them records which restore to us the history of + that long-forgotten people in such detail as it was not known to any + previous generation since the fall of Nineveh. For two thousand five + hundred years no one saw these treasures or knew that they existed. One + hundred generations of men came and went without once pronouncing the name + of kings Shalmaneser or Asumazirpal or Asurbanipal. And to-day, after + these centuries of oblivion, these names are restored to history, and, + thanks to the character of their monuments, are assured a permanency of + fame that can almost defy time itself. It would be nothing strange, but + rather in keeping with their previous mutations of fortune, if the names + of Asurnazirpal and Asurbanipal should be familiar as household words to + future generations that have forgotten the existence of an Alexander, a + Caesar, and a Napoleon. For when Macaulay's prospective New Zealander + explores the ruins of the British Museum the records of the ancient + Assyrians will presumably still be there unscathed, to tell their story as + they have told it to our generation, though every manuscript and printed + book may have gone the way of fragile textures. + </p> + <p> + But the past of the Assyrian sculptures is quite necromantic enough + without conjuring for them a necromantic future. The story of their + restoration is like a brilliant romance of history. Prior to the middle of + this century the inquiring student could learn in an hour or so all that + was known in fact and in fable of the renowned city of Nineveh. He had but + to read a few chapters of the Bible and a few pages of Diodorus to exhaust + the important literature on the subject. If he turned also to the pages of + Herodotus and Xenophon, of Justin and Aelian, these served chiefly to + confirm the suspicion that the Greeks themselves knew almost nothing more + of the history of their famed Oriental forerunners. The current fables + told of a first King Ninus and his wonderful queen Semiramis; of + Sennacherib the conqueror; of the effeminate Sardanapalus, who neglected + the warlike ways of his ancestors but perished gloriously at the last, + with Nineveh itself, in a self-imposed holocaust. And that was all. How + much of this was history, how much myth, no man could say; and for all any + one suspected to the contrary, no man could ever know. And to-day the + contemporary records of the city are before us in such profusion as no + other nation of antiquity, save Egypt alone, can at all rival. Whole + libraries of Assyrian books are at hand that were written in the seventh + century before our era. These, be it understood, are the original books + themselves, not copies. The author of that remote time appeals to us + directly, hand to eye, without intermediary transcriber. And there is not + a line of any Hebrew or Greek manuscript of a like age that has been + preserved to us; there is little enough that can match these ancient books + by a thousand years. When one reads Moses or Isaiah, Homer, Hesiod, or + Herodotus, he is but following the transcription—often + unquestionably faulty and probably never in all parts perfect—of + successive copyists of later generations. The oldest known copy of the + Bible, for example, dates probably from the fourth century A.D., a + thousand years or more after the last Assyrian records were made and read + and buried and forgotten. + </p> + <p> + There was at least one king of Assyria—namely, Asurbanipal, whose + palace boasted a library of some ten thousand volumes—a library, if + you please, in which the books were numbered and shelved systematically, + and classified and cared for by an official librarian. If you would see + some of the documents of this marvellous library you have but to step past + the winged lions of Asurnazirpal and enter the Assyrian hall just around + the corner from the Rosetta Stone. Indeed, the great slabs of stone from + which the lions themselves are carved are in a sense books, inasmuch as + there are written records inscribed on their surface. A glance reveals the + strange characters in which these records are written, graven neatly in + straight lines across the stone, and looking to casual inspection like + nothing so much as random flights of arrow-heads. The resemblance is so + striking that this is sometimes called the arrow-head character, though it + is more generally known as the wedge or cuneiform character. The + inscriptions on the flanks of the lions are, however, only makeshift + books. But the veritable books are no farther away than the next room + beyond the hall of Asurnazirpal. They occupy part of a series of cases + placed down the centre of this room. Perhaps it is not too much to speak + of this collection as the most extraordinary set of documents of all the + rare treasures of the British Museum, for it includes not books alone, but + public and private letters, business announcements, marriage contracts—in + a word, all the species of written records that enter into the every-day + life of an intelligent and cultured community. + </p> + <p> + But by what miracle have such documents been preserved through all these + centuries? A glance makes the secret evident. It is simply a case of + time-defying materials. Each one of these Assyrian documents appears to + be, and in reality is, nothing more or less than an inscribed fragment of + brick, having much the color and texture of a weathered terra-cotta tile + of modern manufacture. These slabs are usually oval or oblong in shape, + and from two or three to six or eight inches in length and an inch or so + in thickness. Each of them was originally a portion of brick-clay, on + which the scribe indented the flights of arrowheads with some + sharp-cornered instrument, after which the document was made permanent by + baking. They are somewhat fragile, of course, as all bricks are, and many + of them have been more or less crumbled in the destruction of the palace + at Nineveh; but to the ravages of mere time they are as nearly + invulnerable as almost anything in nature. Hence it is that these records + of a remote civilization have been preserved to us, while the similar + records of such later civilizations as the Grecian have utterly perished, + much as the flint implements of the cave-dweller come to us unchanged, + while the iron implements of a far more recent age have crumbled away. + </p> + <p> + HOW THE RECORDS WERE READ + </p> + <p> + After all, then, granted the choice of materials, there is nothing so very + extraordinary in the mere fact of preservation of these ancient records. + To be sure, it is vastly to the credit of nineteenth-century enterprise to + have searched them out and brought them back to light. But the real marvel + in connection with them is the fact that nineteenth-century scholarship + should have given us, not the material documents themselves, but a + knowledge of their actual contents. The flight of arrow-heads on wall or + slab or tiny brick have surely a meaning; but how shall we guess that + meaning? These must be words; but what words? The hieroglyphics of the + Egyptians were mysterious enough in all conscience; yet, after all, their + symbols have a certain suggestiveness, whereas there is nothing that seems + to promise a mental leverage in the unbroken succession of these cuneiform + dashes. Yet the Assyrian scholar of to-day can interpret these strange + records almost as readily and as surely as the classical scholar + interprets a Greek manuscript. And this evidences one of the greatest + triumphs of nineteenth-century scholarship, for within almost two thousand + years no man has lived, prior to our century, to whom these strange + inscriptions would not have been as meaningless as they are to the most + casual stroller who looks on them with vague wonderment here in the museum + to-day. For the Assyrian language, like the Egyptian, was veritably a dead + language; not, like Greek and Latin, merely passed from practical + every-day use to the closet of the scholar, but utterly and absolutely + forgotten by all the world. Such being the case, it is nothing less than + marvellous that it should have been restored. + </p> + <p> + It is but fair to add that this restoration probably never would have been + effected, with Assyrian or with Egyptian, had the language in dying left + no cognate successor; for the powers of modern linguistry, though great, + are not actually miraculous. But, fortunately, a language once developed + is not blotted out in toto; it merely outlives its usefulness and is + gradually supplanted, its successor retaining many traces of its origin. + So, just as Latin, for example, has its living representatives in Italian + and the other Romance tongues, the language of Assyria is represented by + cognate Semitic languages. As it chances, however, these have been of aid + rather in the later stages of Assyrian study than at the very outset; and + the first clew to the message of the cuneiform writing came through a + slightly different channel. + </p> + <p> + Curiously enough, it was a trilingual inscription that gave the clew, as + in the case of the Rosetta Stone, though with very striking difference + withal. The trilingual inscription now in question, instead of being a + small, portable monument, covers the surface of a massive bluff at + Behistun in western Persia. Moreover, all three of its inscriptions are in + cuneiform characters, and all three are in languages that at the beginning + of our century were absolutely unknown. This inscription itself, as a + striking monument of unknown import, had been seen by successive + generations. Tradition ascribed it, as we learn from Ctesias, through + Diodorus, to the fabled Assyrian queen Semiramis. Tradition was quite at + fault in this; but it is only recently that knowledge has availed to set + it right. The inscription, as is now known, was really written about the + year 515 B.C., at the instance of Darius I., King of Persia, some of whose + deeds it recounts in the three chief languages of his widely scattered + subjects. + </p> + <p> + The man who at actual risk of life and limb copied this wonderful + inscription, and through interpreting it became the veritable "father of + Assyriology," was the English general Sir Henry Rawlinson. His feat was + another British triumph over the same rivals who had competed for the + Rosetta Stone; for some French explorers had been sent by their + government, some years earlier, expressly to copy this strange record, and + had reported that it was impossible to reach the inscription. But British + courage did not find it so, and in 1835 Rawlinson scaled the dangerous + height and made a paper cast of about half the inscription. Diplomatic + duties called him away from the task for some years, but in 1848 he + returned to it and completed the copy of all parts of the inscription that + have escaped the ravages of time. And now the material was in hand for a + new science, which General Rawlinson himself soon, assisted by a host of + others, proceeded to elaborate. + </p> + <p> + The key to the value of this unique inscription lies in the fact that its + third language is ancient Persian. It appears that the ancient Persians + had adopted the cuneiform character from their western neighbors, the + Assyrians, but in so doing had made one of those essential modifications + and improvements which are scarcely possible to accomplish except in the + transition from one race to another. Instead of building with the + arrow-head a multitude of syllabic characters, including many homophones, + as had been and continued to be the custom with the Assyrians, the + Persians selected a few of these characters and ascribed to them phonetic + values that were almost purely alphabetic. In a word, while retaining the + wedge as the basal stroke of their script, they developed an alphabet, + making the last wonderful analysis of phonetic sounds which even to this + day has escaped the Chinese, which the Egyptians had only partially + effected, and which the Phoenicians were accredited by the Greeks with + having introduced to the Western world. In addition to this all-essential + step, the Persians had introduced the minor but highly convenient custom + of separating the words of a sentence from one another by a particular + mark, differing in this regard not only from the Assyrians and Egyptians, + but from the early Greek scribes as well. + </p> + <p> + Thanks to these simplifications, the old Persian language had been + practically restored about the beginning of the nineteenth century, + through the efforts of the German Grotefend, and further advances in it + were made just at this time by Renouf, in France, and by Lassen, in + Germany, as well as by Rawlinson himself, who largely solved the problem + of the Persian alphabet independently. So the Persian portion of the + Behistun inscription could be at least partially deciphered. This in + itself, however, would have been no very great aid towards the restoration + of the languages of the other portions had it not chanced, fortunately, + that the inscription is sprinkled with proper names. Now proper names, + generally speaking, are not translated from one language to another, but + transliterated as nearly as the genius of the language will permit. It was + the fact that the Greek word Ptolemaics was transliterated on the Rosetta + Stone that gave the first clew to the sounds of the Egyptian characters. + Had the upper part of the Rosetta Stone been preserved, on which, + originally, there were several other names, Young would not have halted + where he did in his decipherment. + </p> + <p> + But fortune, which had been at once so kind and so tantalizing in the case + of the Rosetta Stone, had dealt more gently with the Behistun + inscriptions; for no fewer than ninety proper names were preserved in the + Persian portion and duplicated, in another character, in the Assyrian + inscription. A study of these gave a clew to the sounds of the Assyrian + characters. The decipherment of this character, however, even with this + aid, proved enormously difficult, for it was soon evident that here it was + no longer a question of a nearly perfect alphabet of a few characters, but + of a syllabary of several hundred characters, including many homophones, + or different forms for representing the same sound. But with the Persian + translation for a guide on the one hand, and the Semitic languages, to + which family the Assyrian belonged, on the other, the appalling task was + gradually accomplished, the leading investigators being General Rawlinson, + Professor Hincks, and Mr. Fox-Talbot, in England, Professor Jules Oppert, + in Paris, and Professor Julian Schrader, in Germany, though a host of + other scholars soon entered the field. + </p> + <p> + This great linguistic feat was accomplished about the middle of the + nineteenth century. But so great a feat was it that many scholars of the + highest standing, including Joseph Erneste Renan, in France, and Sir G. + Cornewall Lewis, in England, declined at first to accept the results, + contending that the Assyriologists had merely deceived themselves by + creating an arbitrary language. The matter was put to a test in 1855 at + the suggestion of Mr. Fox-Talbot, when four scholars, one being Mr. Talbot + himself and the others General Rawlinson, Professor Hincks, and Professor + Oppert, laid before the Royal Asiatic Society their independent + interpretations of a hitherto untranslated Assyrian text. A committee of + the society, including England's greatest historian of the century, George + Grote, broke the seals of the four translations, and reported that they + found them unequivocally in accord as regards their main purport, and even + surprisingly uniform as regards the phraseology of certain passages—in + short, as closely similar as translations from the obscure texts of any + difficult language ever are. This decision gave the work of the + Assyriologists official status, and the reliability of their method has + never since been in question. Henceforth Assyriology was an established + science. + </p> + <p> + <a name="link2H_APPE" id="link2H_APPE"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + APPENDIX + </h2> +<pre xml:space="preserve"> + REFERENCE-LIST + + CHAPTER I. MODERN DEVELOPMENT OF THE PHYSICAL SCIENCES + + (1) Robert Boyle, Philosophical Works (3 vols.). London, 1738. + + CHAPTER II. THE BEGINNINGS OF MODERN CHEMISTRY + + (1) For a complete account of the controversy called the "Water + Controversy," see The Life of the Hon. Henry Cavendish, by George + Wilson, M.D., F.R.S.E. London, 1850. + + (2) Henry Cavendish, in Phil. Trans. for 1784, P. 119. + + (3) Lives of the Philosophers of the Time of George III., by Henry, Lord + Brougham, F.R.S., p. 106. London, 1855. + + (4) Experiments and Observations on Different Kinds of Air, by Joseph + Priestley (3 vols.). Birmingham, 790, vol. II, pp. 103-107. + + (5) Lectures on Experimental Philosophy, by Joseph Priestley, lecture + IV., pp. 18, ig. J. Johnson, London, 1794. + + (6) Translated from Scheele's Om Brunsten, eller Magnesia, och dess + Egenakaper. Stockholm, 1774, and published as Alembic Club Reprints, No. + 13, 1897, p. 6. + + (7) According to some writers this was discovered by Berzelius. + + (8) Histoire de la Chimie, par Ferdinand Hoefer. Paris, 1869, Vol. CL, + p. 289. + + (9) Elements of Chemistry, by Anton Laurent Lavoisier, translated by + Robert Kerr, p. 8. London and Edinburgh, 1790. + + (10) Ibid., pp. 414-416. + + CHAPTER III. CHEMISTRY SINCE THE TIME OF DALTON + + (1) Sir Humphry Davy, in Phil. Trans., Vol. VIII. + + CHAPTER IV. ANATOMY AND PHYSIOLOGY IN THE EIGHTEENTH CENTURY + + (1) Baas, History of Medicine, p. 692. + + (2) Based on Thomas H. Huxley's Presidential Address to the British + Association for the Advancement of Science, 1870. + + (3) Essays on Digestion, by James Carson. London, 1834, p. 6. + + (4) Ibid., p. 7. + + (5) John Hunter, On the Digestion of the Stomach after Death, first + edition, pp. 183-188. + + (6) Erasmus Darwin, The Botanic Garden, pp. 448-453. London, 1799. + + CHAPTER V. ANATOMY AND PHYSIOLOGY IN THE NINETEENTH CENTURY + + (1) Baron de Cuvier's Theory of the Earth. New York, 1818, p. 123. + + (2) On the Organs and Mode of Fecundation of Orchidex and Asclepiadea, + by Robert Brown, Esq., in Miscellaneous Botanical Works. London, 1866, + Vol. I., pp. 511-514. + + (3) Justin Liebig, Animal Chemistry. London, 1843, p. 17f. + + CHAPTER VI. THEORIES OF ORGANIC EVOLUTION + + (1) "Essay on the Metamorphoses of Plants," by Goethe, translated + for the present work from Grundriss einer Geschichte der + Naturwissenschaften, by Friederich Dannemann (2 vols.). Leipzig, 1896, + Vol. I., p. 194. + + (2) The Temple of Nature, or The Origin of Society, by Erasmus Darwin, + edition published in 1807, p. 35. + + (3) Baron de Cuvier, Theory of the Earth. New York, 1818, p.74. (This + was the introduction to Cuvier's great work.) + + (4) Robert Chambers, Explanations: a sequel to Vestiges of Creation. + London, Churchill, 1845, pp. 148-153. + + CHAPTER VII. EIGHTEENTH-CENTURY MEDICINE + + (1) Condensed from Dr. Boerhaave's Academical Lectures on the Theory of + Physic. London, 1751, pp. 77, 78. Boerhaave's lectures were published as + Aphorismi de cognoscendis et curandis Morbis, Leyden, 1709. On this + book Van Swieten wrote commentaries filling five volumes. Another very + celebrated work of Boerhaave is his Institutiones et Experimenta + Chemic, Paris, 1724, the germs of this being given as a lecture on his + appointment to the chair of chemistry in the University of Leyden in + 1718. + + (2) An Inquiry into the Causes and Effects of the Variola Vaccine, etc., + by Edward Jenner, M.D., F.R.S., etc. London, 1799, pp. 2-7. He wrote + several other papers, most of which were communications to the Royal + Society. His last publication was, On the Influence of Artificial + Eruptions in Certain Diseases (London, 1822), a subject to which he had + given much time and study. + + CHAPTER VIII. NINETEENTH-CENTURY MEDICINE + + (1) In the introduction to Corvisart's translation of Avenbrugger's + work. Paris, 1808. + + (2) Laennec, Traite d'Auscultation Mediate. Paris, 1819. This was + Laennec's chief work, and was soon translated into several different + languages. Before publishing this he had written also, Propositions sur + la doctrine midicale d'Hippocrate, Paris, 1804, and Memoires sur les + vers visiculaires, in the same year. + + (3) Researches, Chemical and Philosophical, chiefly concerning Nitrous + Oxide or Dephlogisticated Nitrous Air and its Respiration, by Humphry + Davy. London, 1800, pp. 479-556. + + (4) Ibid. + + (5) For accounts of the discovery of anaesthesia, see Report of the + Board of Trustees of the Massachusetts General Hospital, Boston, 1888. + Also, The Ether Controversy: Vindication of the Hospital Reports of + 1848, by N. L Bowditch, Boston, 1848. An excellent account is given in + Littell's Living Age, for March, 1848, written by R. H. Dana, Jr. There + are also two Congressional Reports on the question of the discovery of + etherization, one for 1848, the other for 11852. + + (6) Simpson made public this discovery of the anaesthetic properties + of chloroform in a paper read before the Medico-Chirurgical Society of + Edinburgh, in March, 1847, about three months after he had first seen + a surgical operation performed upon a patient to whom ether had been + administered. + + (7) Louis Pasteur, Studies on Fermentation. London, 1870. + + (8) Louis Pasteur, in Comptes Rendus des Sciences de L'Academie des + Sciences, vol. XCII., 1881, pp. 429-435. + + CHAPTER IX. THE NEW SCIENCE OF EXPERIMENTAL PSYCHOLOGY + + (1) Bell's communications were made to the Royal Society, but his + studies and his discoveries in the field of anatomy of the nervous + system were collected and published, in 1824, as An Exposition of the + Natural System of Nerves of the Human Body: being a Republication of the + Papers delivered to the Royal Society on the Subject of the Nerves. + + (2) Marshall Hall, M.D., F.R.S.L., On the Reflex Functions of the + Medulla Oblongata and the Medulla Spinalis, in Phil. Trans. of Royal + Soc., vol. XXXIII., 1833. +</pre> + <p> + <br /> <br /> + </p> + <hr /> + <hr /> + <p> + <br /> <br /> + </p> + <h1> + TABLE OF CONTENTS <br /><br /> FOR THE FIVE VOLUMES + </h1> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0002"> <b>BOOK + I</b> </a> + </p> + <table summary="" style="margin-right: auto; margin-left: auto"> + <tr> + <td> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0003"> + I. PREHISTORIC SCIENCE </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0004"> + II. EGYPTIAN SCIENCE </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0005"> + III. SCIENCE OF BABYLONIA AND ASSYRIA </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0006"> + IV. THE DEVELOPMENT OF THE ALPHABET </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0007"> + V. THE BEGINNINGS OF GREEK SCIENCE </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0008"> + VI. THE EARLY GREEK PHILOSOPHERS IN ITALY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0009"> + VII. GREEK SCIENCE IN THE EARLY ATTIC PERIOD </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0010"> + VIII. POST-SOCRATIC SCIENCE AT ATHENS—PLATO, ARISTOTLE, AND + THEOPHRASTUS </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0011"> + IX. GREEK SCIENCE OF THE ALEXANDRIAN OR HELLENISTIC PERIOD </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0012"> + X. SCIENCE OF THE ROMAN PERIOD </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1705/1705-h/1705-h.htm#2H_4_0013"> + XI. A RETROSPECTIVE GLANCE AT CLASSICAL SCIENCE </a> + </p> + </td> + </tr> + </table> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0002"> <b>BOOK + II. THE BEGINNINGS OF MODERN SCIENCE</b> </a> + </p> + <table summary="" style="margin-right: auto; margin-left: auto"> + <tr> + <td> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0003"> + I. SCIENCE IN THE DARK AGE </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0004"> + II. MEDIAEVAL SCIENCE AMONG THE ARABIANS </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0005"> + III. MEDIAEVAL SCIENCE IN THE WEST </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0006"> + IV. THE NEW COSMOLOGY—COPERNICUS TO KEPLER AND GALILEO </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0007"> + V. GALILEO AND THE NEW PHYSICS </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0008"> + VI. TWO PSEUDO-SCIENCES—ALCHEMY AND ASTROLOGY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0009"> + VII. FROM PARACELSUS TO HARVEY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0010"> + VIII. MEDICINE IN THE SIXTEENTH AND SEVENTEENTH CENTURIES </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0011"> + IX. PHILOSOPHER-SCIENTISTS AND NEW INSTITUTIONS OF LEARNING </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0012"> + X. THE SUCCESSORS OF GALILEO IN PHYSICAL SCIENCE </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0013"> + XI. NEWTON AND THE COMPOSITION OF LIGHT </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0014"> + XII. NEWTON AND THE LAW OF GRAVITATION </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0015"> + XIII. INSTRUMENTS OF PRECISION IN THE AGE OF NEWTON </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0016"> + XIV. PROGRESS IN ELECTRICITY FROM GILBERT AND VON GUERICKE TO + FRANKLIN </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1706/1706-h/1706-h.htm#2H_4_0017"> + XV. NATURAL HISTORY TO THE TIME OF LINNAEUS </a> + </p> + </td> + </tr> + </table> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0001"> <b>BOOK + III. MODERN DEVELOPMENT OF THE PHYSICAL SCIENCES</b> </a> + </p> + <table summary="" style="margin-right: auto; margin-left: auto"> + <tr> + <td> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0002"> + I. THE SUCCESSORS OF NEWTON IN ASTRONOMY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0003"> + II. THE PROGRESS OF MODERN ASTRONOMY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0004"> + III. THE NEW SCIENCE OF PALEONTOLOGY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0005"> + IV. THE ORIGIN AND DEVELOPMENT OF MODERN GEOLOGY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0006"> + V. THE NEW SCIENCE OF METEOROLOGY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0007"> + VI. MODERN THEORIES OF HEAT AND LIGHT </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0008"> + VII. THE MODERN DEVELOPMENT OF ELECTRICITY AND MAGNETISM </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0009"> + VIII. THE CONSERVATION OF ENERGY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1707/1707-h/1707-h.htm#2H_4_0010"> + IX. THE ETHER AND PONDERABLE MATTER </a> + </p> + </td> + </tr> + </table> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0001"> <b>BOOK + IV. MODERN DEVELOPMENT OF THE CHEMICAL AND BIOLOGICAL SCIENCES</b> </a> + </p> + <table summary="" style="margin-right: auto; margin-left: auto"> + <tr> + <td> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0002"> + I. THE PHLOGISTON THEORY IN CHEMISTRY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0003"> + II. THE BEGINNINGS OF MODERN CHEMISTRY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0004"> + III. CHEMISTRY SINCE THE TIME OF DALTON </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0005"> + IV. ANATOMY AND PHYSIOLOGY IN THE EIGHTEENTH CENTURY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0006"> + V. ANATOMY AND PHYSIOLOGY IN THE NINETEENTH CENTURY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0007"> + VI. THEORIES OF ORGANIC EVOLUTION </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0008"> + VII. EIGHTEENTH-CENTURY MEDICINE </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0009"> + VIII. NINETEENTH-CENTURY MEDICINE </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0010"> + IX. THE NEW SCIENCE OF EXPERIMENTAL PSYCHOLOGY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/1708/1708-h/1708-h.htm#2H_4_0011"> + X. THE NEW SCIENCE OF ORIENTAL ARCHAEOLOGY </a> + </p> + </td> + </tr> + </table> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0001"> + <b>BOOK V. ASPECTS OF RECENT SCIENCE</b> </a><br /> + </p> + <table summary="" style="margin-right: auto; margin-left: auto"> + <tr> + <td> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0003"> + I. THE BRITISH MUSEUM </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0004"> + II. THE ROYAL SOCIETY OF LONDON FOR IMPROVING NATURAL KNOWLEDGE </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0005"> + III. THE ROYAL INSTITUTION AND THE LOW-TEMPERATURE RESEARCHES </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0006"> + IV. SOME PHYSICAL LABORATORIES AND PHYSICAL PROBLEMS </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0007"> + V. THE MARINE BIOLOGICAL LABORATORY AT NAPLES </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0008"> + VI. ERNST HAECKEL AND THE NEW ZOOLOGY </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0009"> + VII. SOME MEDICAL LABORATORIES AND MEDICAL PROBLEMS </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0010"> + VII. SOME UNSOLVED SCIENTIFIC PROBLEMS </a> + </p> + <p class="toc"> + <a + href="http://www.gutenberg.org/files/30495/30495-h/30495-h.htm#2H_4_0011"> + IX. RETROSPECT AND PROSPECT </a> + </p> + </td> + </tr> + </table> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> + </p> +<pre xml:space="preserve"> + + + + + +End of the Project Gutenberg EBook of A History of Science, Volume 4(of 5), by +Henry Smith Williams + +*** END OF THIS PROJECT GUTENBERG EBOOK HISTORY OF SCIENCE, V4 *** + +***** This file should be named 1708-h.htm or 1708-h.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/1/7/0/1708/ + +Produced by Charles Keller, and David Widger + + +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. Special rules, +set forth in the General Terms of Use part of this license, apply to +copying and distributing Project Gutenberg-tm electronic works to +protect the PROJECT GUTENBERG-tm concept and trademark. Project +Gutenberg is a registered trademark, and may not be used if you +charge for the eBooks, unless you receive specific permission. If you +do not charge anything for copies of this eBook, complying with the +rules is very easy. You may use this eBook for nearly any purpose +such as creation of derivative works, reports, performances and +research. They may be modified and printed and given away--you may do +practically ANYTHING with public domain eBooks. Redistribution is +subject to the trademark license, especially commercial +redistribution. + + + +*** START: FULL LICENSE *** + +THE FULL PROJECT GUTENBERG LICENSE +PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK + +To protect the Project Gutenberg-tm mission of promoting the free +distribution of electronic works, by using or distributing this work +(or any other work associated in any way with the phrase "Project +Gutenberg"), you agree to comply with all the terms of the Full Project +Gutenberg-tm License (available with this file or online at +http://gutenberg.org/license). + + +Section 1. General Terms of Use and Redistributing Project Gutenberg-tm +electronic works + +1.A. By reading or using any part of this Project Gutenberg-tm +electronic work, you indicate that you have read, understand, agree to +and accept all the terms of this license and intellectual property +(trademark/copyright) agreement. If you do not agree to abide by all +the terms of this agreement, you must cease using and return or destroy +all copies of Project Gutenberg-tm electronic works in your possession. +If you paid a fee for obtaining a copy of or access to a Project +Gutenberg-tm electronic work and you do not agree to be bound by the +terms of this agreement, you may obtain a refund from the person or +entity to whom you paid the fee as set forth in paragraph 1.E.8. + +1.B. "Project Gutenberg" is a registered trademark. It may only be +used on or associated in any way with an electronic work by people who +agree to be bound by the terms of this agreement. There are a few +things that you can do with most Project Gutenberg-tm electronic works +even without complying with the full terms of this agreement. See +paragraph 1.C below. There are a lot of things you can do with Project +Gutenberg-tm electronic works if you follow the terms of this agreement +and help preserve free future access to Project Gutenberg-tm electronic +works. See paragraph 1.E below. + +1.C. The Project Gutenberg Literary Archive Foundation ("the Foundation" +or PGLAF), owns a compilation copyright in the collection of Project +Gutenberg-tm electronic works. Nearly all the individual works in the +collection are in the public domain in the United States. If an +individual work is in the public domain in the United States and you are +located in the United States, we do not claim a right to prevent you from +copying, distributing, performing, displaying or creating derivative +works based on the work as long as all references to Project Gutenberg +are removed. Of course, we hope that you will support the Project +Gutenberg-tm mission of promoting free access to electronic works by +freely sharing Project Gutenberg-tm works in compliance with the terms of +this agreement for keeping the Project Gutenberg-tm name associated with +the work. You can easily comply with the terms of this agreement by +keeping this work in the same format with its attached full Project +Gutenberg-tm License when you share it without charge with others. + +1.D. The copyright laws of the place where you are located also govern +what you can do with this work. Copyright laws in most countries are in +a constant state of change. If you are outside the United States, check +the laws of your country in addition to the terms of this agreement +before downloading, copying, displaying, performing, distributing or +creating derivative works based on this work or any other Project +Gutenberg-tm work. The Foundation makes no representations concerning +the copyright status of any work in any country outside the United +States. + +1.E. Unless you have removed all references to Project Gutenberg: + +1.E.1. The following sentence, with active links to, or other immediate +access to, the full Project Gutenberg-tm License must appear prominently +whenever any copy of a Project Gutenberg-tm work (any work on which the +phrase "Project Gutenberg" appears, or with which the phrase "Project +Gutenberg" is associated) is accessed, displayed, performed, viewed, +copied or distributed: + +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 + +1.E.2. If an individual Project Gutenberg-tm electronic work is derived +from the public domain (does not contain a notice indicating that it is +posted with permission of the copyright holder), the work can be copied +and distributed to anyone in the United States without paying any fees +or charges. If you are redistributing or providing access to a work +with the phrase "Project Gutenberg" associated with or appearing on the +work, you must comply either with the requirements of paragraphs 1.E.1 +through 1.E.7 or obtain permission for the use of the work and the +Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or +1.E.9. + +1.E.3. If an individual Project Gutenberg-tm electronic work is posted +with the permission of the copyright holder, your use and distribution +must comply with both paragraphs 1.E.1 through 1.E.7 and any additional +terms imposed by the copyright holder. Additional terms will be linked +to the Project Gutenberg-tm License for all works posted with the +permission of the copyright holder found at the beginning of this work. + +1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm +License terms from this work, or any files containing a part of this +work or any other work associated with Project Gutenberg-tm. + +1.E.5. Do not copy, display, perform, distribute or redistribute this +electronic work, or any part of this electronic work, without +prominently displaying the sentence set forth in paragraph 1.E.1 with +active links or immediate access to the full terms of the Project +Gutenberg-tm License. + +1.E.6. You may convert to and distribute this work in any binary, +compressed, marked up, nonproprietary or proprietary form, including any +word processing or hypertext form. However, if you provide access to or +distribute copies of a Project Gutenberg-tm work in a format other than +"Plain Vanilla ASCII" or other format used in the official version +posted on the official Project Gutenberg-tm web site (www.gutenberg.org), +you must, at no additional cost, fee or expense to the user, provide a +copy, a means of exporting a copy, or a means of obtaining a copy upon +request, of the work in its original "Plain Vanilla ASCII" or other +form. Any alternate format must include the full Project Gutenberg-tm +License as specified in paragraph 1.E.1. + +1.E.7. Do not charge a fee for access to, viewing, displaying, +performing, copying or distributing any Project Gutenberg-tm works +unless you comply with paragraph 1.E.8 or 1.E.9. + +1.E.8. You may charge a reasonable fee for copies of or providing +access to or distributing Project Gutenberg-tm electronic works provided +that + +- You pay a royalty fee of 20% of the gross profits you derive from + the use of Project Gutenberg-tm works calculated using the method + you already use to calculate your applicable taxes. The fee is + owed to the owner of the Project Gutenberg-tm trademark, but he + has agreed to donate royalties under this paragraph to the + Project Gutenberg Literary Archive Foundation. Royalty payments + must be paid within 60 days following each date on which you + prepare (or are legally required to prepare) your periodic tax + returns. Royalty payments should be clearly marked as such and + sent to the Project Gutenberg Literary Archive Foundation at the + address specified in Section 4, "Information about donations to + the Project Gutenberg Literary Archive Foundation." + +- You provide a full refund of any money paid by a user who notifies + you in writing (or by e-mail) within 30 days of receipt that s/he + does not agree to the terms of the full Project Gutenberg-tm + License. You must require such a user to return or + destroy all copies of the works possessed in a physical medium + and discontinue all use of and all access to other copies of + Project Gutenberg-tm works. + +- You provide, in accordance with paragraph 1.F.3, a full refund of any + money paid for a work or a replacement copy, if a defect in the + electronic work is discovered and reported to you within 90 days + of receipt of the work. + +- You comply with all other terms of this agreement for free + distribution of Project Gutenberg-tm works. + +1.E.9. If you wish to charge a fee or distribute a Project Gutenberg-tm +electronic work or group of works on different terms than are set +forth in this agreement, you must obtain permission in writing from +both the Project Gutenberg Literary Archive Foundation and Michael +Hart, the owner of the Project Gutenberg-tm trademark. Contact the +Foundation as set forth in Section 3 below. + +1.F. + +1.F.1. Project Gutenberg volunteers and employees expend considerable +effort to identify, do copyright research on, transcribe and proofread +public domain works in creating the Project Gutenberg-tm +collection. Despite these efforts, Project Gutenberg-tm electronic +works, and the medium on which they may be stored, may contain +"Defects," such as, but not limited to, incomplete, inaccurate or +corrupt data, transcription errors, a copyright or other intellectual +property infringement, a defective or damaged disk or other medium, a +computer virus, or computer codes that damage or cannot be read by +your equipment. + +1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right +of Replacement or Refund" described in paragraph 1.F.3, the Project +Gutenberg Literary Archive Foundation, the owner of the Project +Gutenberg-tm trademark, and any other party distributing a Project +Gutenberg-tm electronic work under this agreement, disclaim all +liability to you for damages, costs and expenses, including legal +fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT +LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE +PROVIDED IN PARAGRAPH F3. YOU AGREE THAT THE FOUNDATION, THE +TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE +LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR +INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH +DAMAGE. + +1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a +defect in this electronic work within 90 days of receiving it, you can +receive a refund of the money (if any) you paid for it by sending a +written explanation to the person you received the work from. If you +received the work on a physical medium, you must return the medium with +your written explanation. The person or entity that provided you with +the defective work may elect to provide a replacement copy in lieu of a +refund. If you received the work electronically, the person or entity +providing it to you may choose to give you a second opportunity to +receive the work electronically in lieu of a refund. If the second copy +is also defective, you may demand a refund in writing without further +opportunities to fix the problem. + +1.F.4. Except for the limited right of replacement or refund set forth +in paragraph 1.F.3, this work is provided to you 'AS-IS' WITH NO OTHER +WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO +WARRANTIES OF MERCHANTIBILITY OR FITNESS FOR ANY PURPOSE. + +1.F.5. Some states do not allow disclaimers of certain implied +warranties or the exclusion or limitation of certain types of damages. +If any disclaimer or limitation set forth in this agreement violates the +law of the state applicable to this agreement, the agreement shall be +interpreted to make the maximum disclaimer or limitation permitted by +the applicable state law. The invalidity or unenforceability of any +provision of this agreement shall not void the remaining provisions. + +1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the +trademark owner, any agent or employee of the Foundation, anyone +providing copies of Project Gutenberg-tm electronic works in accordance +with this agreement, and any volunteers associated with the production, +promotion and distribution of Project Gutenberg-tm electronic works, +harmless from all liability, costs and expenses, including legal fees, +that arise directly or indirectly from any of the following which you do +or cause to occur: (a) distribution of this or any Project Gutenberg-tm +work, (b) alteration, modification, or additions or deletions to any +Project Gutenberg-tm work, and (c) any Defect you cause. + + +Section 2. Information about the Mission of Project Gutenberg-tm + +Project Gutenberg-tm is synonymous with the free distribution of +electronic works in formats readable by the widest variety of computers +including obsolete, old, middle-aged and new computers. It exists +because of the efforts of hundreds of volunteers and donations from +people in all walks of life. + +Volunteers and financial support to provide volunteers with the +assistance they need, are critical to reaching Project Gutenberg-tm's +goals and ensuring that the Project Gutenberg-tm collection will +remain freely available for generations to come. In 2001, the Project +Gutenberg Literary Archive Foundation was created to provide a secure +and permanent future for Project Gutenberg-tm and future generations. +To learn more about the Project Gutenberg Literary Archive Foundation +and how your efforts and donations can help, see Sections 3 and 4 +and the Foundation web page at http://www.pglaf.org. + + +Section 3. Information about the Project Gutenberg Literary Archive +Foundation + +The Project Gutenberg Literary Archive Foundation is a non profit +501(c)(3) educational corporation organized under the laws of the +state of Mississippi and granted tax exempt status by the Internal +Revenue Service. The Foundation's EIN or federal tax identification +number is 64-6221541. Its 501(c)(3) letter is posted at +http://pglaf.org/fundraising. Contributions to the Project Gutenberg +Literary Archive Foundation are tax deductible to the full extent +permitted by U.S. federal laws and your state's laws. + +The Foundation's principal office is located at 4557 Melan Dr. S. +Fairbanks, AK, 99712., but its volunteers and employees are scattered +throughout numerous locations. Its business office is located at +809 North 1500 West, Salt Lake City, UT 84116, (801) 596-1887, email +business@pglaf.org. Email contact links and up to date contact +information can be found at the Foundation's web site and official +page at http://pglaf.org + +For additional contact information: + Dr. Gregory B. Newby + Chief Executive and Director + gbnewby@pglaf.org + + +Section 4. Information about Donations to the Project Gutenberg +Literary Archive Foundation + +Project Gutenberg-tm depends upon and cannot survive without wide +spread public support and donations to carry out its mission of +increasing the number of public domain and licensed works that can be +freely distributed in machine readable form accessible by the widest +array of equipment including outdated equipment. Many small donations +($1 to $5,000) are particularly important to maintaining tax exempt +status with the IRS. + +The Foundation is committed to complying with the laws regulating +charities and charitable donations in all 50 states of the United +States. Compliance requirements are not uniform and it takes a +considerable effort, much paperwork and many fees to meet and keep up +with these requirements. We do not solicit donations in locations +where we have not received written confirmation of compliance. To +SEND DONATIONS or determine the status of compliance for any +particular state visit http://pglaf.org + +While we cannot and do not solicit contributions from states where we +have not met the solicitation requirements, we know of no prohibition +against accepting unsolicited donations from donors in such states who +approach us with offers to donate. + +International donations are gratefully accepted, but we cannot make +any statements concerning tax treatment of donations received from +outside the United States. U.S. laws alone swamp our small staff. + +Please check the Project Gutenberg Web pages for current donation +methods and addresses. Donations are accepted in a number of other +ways including checks, online payments and credit card donations. +To donate, please visit: http://pglaf.org/donate + + +Section 5. General Information About Project Gutenberg-tm electronic +works. + +Professor Michael S. Hart is the originator of the Project Gutenberg-tm +concept of a library of electronic works that could be freely shared +with anyone. For thirty years, he produced and distributed Project +Gutenberg-tm eBooks with only a loose network of volunteer support. + + +Project Gutenberg-tm eBooks are often created from several printed +editions, all of which are confirmed as Public Domain in the U.S. +unless a copyright notice is included. Thus, we do not necessarily +keep eBooks in compliance with any particular paper edition. + + +Most people start at our Web site which has the main PG search facility: + + http://www.gutenberg.org + +This Web site includes information about Project Gutenberg-tm, +including how to make donations to the Project Gutenberg Literary +Archive Foundation, how to help produce our new eBooks, and how to +subscribe to our email newsletter to hear about new eBooks. + + +</pre> + </body> +</html> |