8o2 THE POPULAR SCIENCE MONTHLY, 



ing the practical value of the new conception which he was introduc- 

 ing. 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," says he, " that as medicine is now 

 practiced, it contains little that is very useful ; but, without any desire 

 to depreciate, I am sure that there is no one, even among professional 

 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 diseases of 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 was Descartes 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, f 

 The anti-Cartesians found material for cheap ridicule in these aspira- 

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

 thirteen years which elapsed between the publication of the "Dis- 

 cours " and the death of Descartes, he did not contribute much to their 

 realization. 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 motu animalium," is, to all intents and 

 purposes, a development of Descartes's fundamental concej^tion ; and 

 the same may be said of the physiology and pathology of Boerhaave, 

 whose authority dominated in the medical world of the first half of the 

 eighteenth century. 



With the origin of modern chemistry 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 have dreamed, wei*e 

 offered to the physiologist. And the greater part of the gigantic prog- 

 ress which has been made in the present century, is a justification of 

 the prevision of Descartes. For it consists, essentially, in a more and 

 more complete resolution of the grosser organs of the living body into 

 physico-chemical mechanisms. 



" I shall try to explain our whole bodily machinery in such a way 

 that it v/ill be no more necessary for us to suppose that the soul pro- 

 duces such movements as are not voluntary than it is to think that 

 there is in a clock a soul which causes it to show the hours." \ These 

 words of Descartes might be appropriately taken as a motto by the 

 author of any modern treatise on physiology. 



But, though, as I think, there is no doubt that Descartes was the 

 first to propound the fundamental conception of the living body as a 

 physical mechanism, which is the distinctive feature of modern as 



* " Discours de la Methode," 6c partie, Ed. Cousin, p. 193. f Ibid., pp. 193, 211. 



\ " Dc la Formation du Foetus." 



