344 



NATURE 



\August II, 1881 



and sometimes hitting nature. Tlie matter is not mended if you 

 suppose tlie blind man's iiearinj^ to lie so acute that he can 

 reMster every stage of the struggle and pretty cleirly jircdlct 

 liow it will end. He h id better not meddle at all, until hi^ eyes 

 are opened — until he can seethe exact positijn of theantagoui Is, 

 and make sure of the effect of his blows, but that which it 

 behoves the physician to sec, not indeed with his bodily eye, but 

 with clear intellectual vision, is a process, and the chain of causa- 

 tion involved in that process. Disease, as we have seen, is a 

 perturbation of the normal activities of a living body ; and it is, 

 and must remain, uirintelligible, so long as we are ignorant of 

 the nature of these normal activities. — In other words, there 

 could be no real science of pattiulogy, until the science of 

 physiology had reached a degree of perfection unattained, and 

 indeed unatfainahle, until quite recent tiuae.^. 



So far as medicine is concerned, 1 am not sure that physiology, 

 such as it was down to the time of Harvey, might as well not 

 have existed. Nay, it is perhaps no exaifgeraiion to say, that 

 within the memory of living men, justly renowned practitioners 

 of medicine and surgery knew less physiology than is now to be 

 learned from the most elementary texl-hook ; and, beyond a few 

 broad facts, rejarded what they did know, as of extra nelyliltle 

 practical im I ortance. Ni)r am I disposed to blame them for 

 this conclu ion ; physiology must be usele-s, or worse than 

 useless, to pathology, so long as its fundamental conseptions are 

 erroneous. 



Harvey is often said to be the founder of modern physiology ; 

 and there can be no question ihat the elucidations of the function 

 of the heart, of the nature of the pulse, and of the course of 

 the blood, put forth in the ever-meLuor.abIe little essay " \ii 

 motu cordis, ' directly worked a revolution in men's views of 

 the nature and of the concatenition of some of the most im- 

 portant physiological processes among the higher animals ; 

 while, indirectly, their influence was perhaps even more 

 remarkable. 



But, though Harvey made this signal and perennially important 

 contribution to the physiolccy of the moderns, his general con- 

 ception of vital processes was es entially identical with that of 

 the ancients ; and, i 1 the " Ex^rciiationes de generati me," and 

 notably in the singular chapter "De calid 1 innato," he shows 

 himself a true son of G.ile 1 and of Aristotle. 



For Harvey, the blood jossesses powers superior to those of 

 the elements ; it is the seat of a soul which is not only vegetative, 

 but also, sen itive and motor. The blood maintains and fashions 

 all parts of the body, "idque summacun providentiaet intellcctu 

 in finem certum agens, quasi ratiocmio quodam uteretur." 



Here is the doctrine of the "pneuim," the product of the 

 philosophical mould into which the animisn of primitive men 

 ran in Greece, in full force. Nor did its strength abate for long 

 after Harvey's time. The same ingrained tendencyof thehu i;an 

 mind to suppose that a process is exjilained when it is ascrilied 

 to a power of which nothing is known except that it is the hypo- 

 thetical agent of the process, gave rise in the next centu.-y to ilie 

 animism of Stahl; and, later, to the doctrine of a vital principle, 

 that "asylum ignirantite " of physiol .gi t-, which has so easily 

 accounted for everything and explained nothing, down to our 

 own times. 



Now the essence of modern, as contrasted with ancient, 

 physiological science, appears to me to lie in its antagonism to 

 animistic hypotheses and animistic phraseoligy. It offers 

 physical expUnations of vital phenomena, or frankly confesses 

 that it has none to offer. And so fjr as i know, ihe first |ier on 

 who gave expression to this modern view of physiology, w h 1 was 

 bold enough to enunciate the proposition that vital phenomena, 

 like all the other phenomena of the physical world, are, in 

 ultimate analysis, resolvable into matter and motion, was Rene 

 Descartes. 



The fifty-four year-; of life of this most original and powerful 

 thinker are widely overlapped, on both sides, by the eighty of 

 Harvey, who survived his youn,;er c .niemporary by seven years, 

 and takes plea-ure in acknowledging the French philosopher's 

 appreciation of his great discovery. 



In fact, Descartes accepted the doctrine of the circulation as 

 propounded by " Herv^eus, melecm d'Angleterre," and gave a 

 full ace junt of it in his first w )rk, the famous " Discoufs ile la 

 Methode," which was published in 1637, only nine ye ir- after the 

 exercitation " De urotu cordis"; and, though differing from 

 Harvey in some important p lints (in which it may be noted, 

 in pasing, Descartes was wrong and Harvey right), he always 

 speaks of him with great respect. And so important does the 



subject seem to Descartes, that he returns to it in the "Traile 

 des Passions," and in the " Traite de I'Homme." 



It is easy to see that Harvey's work must have had a peculiar 

 significance for the subtle thinker, to whom we owe both the 

 spiritualistic and the miterialistic philosophies of modern times. 

 It was in thevery year of its publication, 1628, that Descartes with- 

 drew into that life of solitary investigation and meditation of 

 which his philos iphy was the fruit. And, as the course of his 

 speculations led hira to establish an absolute distinction of nature 

 between the material and the mental worlds, he was logically 

 compelled to seek for the explanation of the phenonena of the ma- 

 terial world within itself ; and having allotted the reilm of thought 

 to the soul, to see nothing but extension and motion in the rest 

 of nature. D--scartes uses "thought"' as the equivalent of om' 

 modern term "c msciousness." Th jught is the function of the 

 s:)ul, and its only function. Our natural heat and all the move- 

 ments of the body, says he, do not depend on the sjul. Death 

 does not take place from any fault of the soul, but only because 

 some of the principal parts of the body become corrupted. The 

 body of a living man differs from that of a dead man in the 

 same way as a «'atch or other auto naton (that is to say a 

 machine whi'-h moves of itself) when it is wound up and has in 

 itself the physical principle of the movements which the mechan- 

 ism is adapted to perform, differs from the same watch, or other 

 machine, when it is broken and the physical principle of its 

 move rent no longer exists. All the actions which nre common 

 to us and the lower animals dei end only on the conformation of 

 our organs and the course which the animal spirits take in the 

 brain, the nerves, and the muscles ; in the same « ay as the 

 movement of a watch is produced by iDthing but the force of its 

 spring and the figui'e of its wheels and other parts. 



De-cartes' Treatise on Man is a sketch of human physiology 

 in which a bold attempt is made to explain all the phenomena 

 of life, except tho e of consciousness, by physical reasonings. 

 To a mind turned in this direction, Harvey's exposition of the 

 heart and vessels as a hydraulic mechanism must have been 

 supremely welcome. 



Descartes was not a mere philosophical tlieorist, but a hard- 

 working dissector and experimenter, and he held the strongest 

 opinion rcspeciing the practical value of the new conception 

 which he was introducing. He speaks of the importance of 

 preserving health, and of the dependence of the mind on the 

 body being so close that perhaps the only way of making men 

 wiser and better than they are, is to be sought in medical science. 

 "It is true," s.ays he, "that as medicine is now practised, it 

 contains little that is very useful ; but without anyi desire to 

 depreciate, I am sure that there is no one, even among profes- 

 sional men, who will not declare that all we know is very little 

 as compared with that which remains to be known ; and that we 

 might escape an infinity of dieasesof the mind, no less than of 

 the body, and even perhaps from the weakness of old age, if we 

 had sufficient knowledge of their causes, and of all the remedies 

 with which nature has provided us. " ' So strongly impressed w^as 

 De-cartes with this, that he resolved to spend the rest of his life 

 in trying to acquire such a knowledge of nature as would lead to 

 the construction of a better medical doctrine.^ The anti- 

 Cartesians found material for ch^-ap ridicule in these aspiraticns 

 of the philosopher : and it is almost needless to say that, in the 

 thirteen years which elapsed between the publication of the 

 "Discours" and the death of Descartes he did not contribute 

 much to their realisation. But, for the next century, all progress 

 in physiology took place along the lines which Descartes laid 

 down. 



The greatest physiological and pathological work of ^ the 

 seventeenth century, Borelli's treatise " De motuanimalium," is, 

 to all intents and purposes, a development of Descartes' funda- 

 mental conception ; and the same may be said of the physiology 

 and pathology of Boeihaave, whose authority dominated in the 

 medical world of the first half of the eighteenth century. 



With the origin of modern chemi-try, and of electrical science, 

 in the latter half of the eighteenth century, aids in the 

 analysis of the phenomena of life, of which Descartes could not 

 havedre.ned, were offered to the physiologist. And thegreater 

 p.art of the gigantic progress which has been made in the present 

 century, is a justification of the prevision of Descartes. For it 

 c insists, essentially, in a more and more complete resolution of 

 the grosser organs of the living body into physico-chemical 

 mechanisms. 



■ " Discours de la Methode," 6e panic, Ed. Cousin, p. 193. 

 ^ Ibid. pp. 193 and 2ii. 



