XIII.] THE BIOLOGICAL SCIENCES AND MEDICINE. 337 



vessels as a hydraulic mechanism must have been 

 supremely welcome. 



Descartes was not a mere philosophical theorist, 

 but a hardworking dissector and experimenter, and he 

 held the strongest opinion respecting 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," says he, " that as medi- 

 cine is now practised, 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. 2 The 

 anti- Cartesians found material for cheap ridicule in 

 these aspirations of the philosopher ; and it is almost 

 needless to say that, in the thirteen years which 

 elapsed between the publication of the "Discours " and 



i " Discours de la Methode," 6 e partie, Ed. Cousin, p. 193 

 2 Ibid. pp. 193 and 211. 

 z 



