THE BIOLOGICAL SCIENCES AND MEDICINE. 345 



way as the movement of a watch is produced by noth- 

 ing but the force of its spring and the figure of its 

 wheels and other parts. 



Descartes' " Treatise on Man " is a sketch of human 

 physiology, in which a bold attempt is made to explain 

 all the phenomena of life, except those of consciousness, 

 by physical reasonings. To a mind turned in this direc- 

 tion, Harvey's exposition of the heart and vessels as a 

 hydraulic mechanism must have been supremely wel- 

 come. 



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 medicine 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 re- 

 mains to be known ; and that we might escape an infin- 

 ity 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 

 * " Discours dc la Methodc," C e partie, Ed. Cousin, p. 193. 



