42 CRITICISM OF MECHANISTIC THEORY 



generally. The finer regulation of growth, 

 nutrition, muscular and nervous functions, 

 was believed to be regulated by the 'vital 

 force.' M tiller had himself taken a prominent 

 part in disproving by his microscopical ob 

 servations on glands the mechanistic theories 

 previously prevailing with regard to secretion, 

 and his numerous observations on growth 

 and development had led him in the same 

 direction. 



Among the younger physiologists about 

 the middle of the century there arose, how 

 ever, a very strong reaction against vitalism 

 and in the direction of mechanistic theories. 

 Schwann, the discoverer of the fact that the 

 bodies of the higher animals are made up of 

 cells, believed that he had also discovered 

 that cells are deposited from the body liquids 

 by a process akin to crystallisation. This 

 hypothesis, of course, struck at the very roots 

 of vitalism. Within the next few years 

 attack after attack was aimed at all the 

 apparent strongholds of vitalism. Du Bois 

 Reymond published observations pointing to 

 an electrical theory of propagation of nerve 

 impulses; Ludwig and others devised new 



