362 BIOLOGICAL SCIENCES AND MEDICINE xiV 



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, 

 were offered to the physiologist. And the greater 

 part of the gigantic progress 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 machin- 

 ery in such a way, that it will be no more necessary 

 for us to suppose that the soul produces such move- 

 ments as are not voluntary, than it is to think that 

 there is in a clock a soul which causes it to show 

 the hours." 1 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 funda- 

 mental conception of the living body as a physical 

 mechanism, which is the distinctive feature of 

 modern, as contrasted with ancient physiology, he 

 was misled by the natural temptation to carry 

 out, in all its details, a parallel between the 

 machines with which he was familiar, such as 

 clocks and pieces of hydraulic apparatus, and the 

 living machine. In all such machines there is a 

 1 De la Formation du Fueius. 



