3G2 BIOLOGICAL SCIENCES AND MEDICINE xiv 



With the origin of modern chemistry, and of 

 electrical science, in the latter half of the eight- 

 eenth century, aids in the analysis of the phenom- 

 ena 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 physi- 

 co-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 supppose that the soul produces 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 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 l)etween 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 



* De la Formation du Foetus. 



