16 SCIENCE PROGRESS. 



The wonderful revolution which the appearance of the 

 Origin of Species produced in the other branch of Biology, 

 promoted the progress of Physiology, by the new interest 

 which it gave to the study, not only of structure and de- 

 velopment, but of all other vital phenomena. It did not, 

 however, in any sensible degree affect our method or alter 

 the direction in which Physiologists had been working for 

 two decades. Its most obvious effect was to sever the two 

 subjects from each other. To the Darwinian epoch Com- 

 parative Anatomy and Physiology were united, but as the 

 new Ontology grew, it became evident that each had its own 

 problems and its own methods of dealing with them. 



The old vitalism of the first half of the century is easily 

 explained. It was generally believed that, on the whole, 

 things went on in the living body as they do outside of 

 it, but when a difficulty arose in so explaining them the 

 Physiologist was ready at once to call in the aid of a 

 " vital force' '. It must not, however, be forgotten that, as I 

 have already indicated, there were great teachers (such, 

 for example, as Sharpey and Allen Thomson in England, 

 Magendie in France, Weber in Germany) who discarded 

 all vitalistic theories, and concerned themselves only with 

 the study of the time- and place-relations of phenomena ; 

 men who were before their time in insight, and were only 

 hindered in their application of chemical and physical prin- 

 ciples to the interpretation of the processes of life by the 

 circumstance that chemical and physical knowledge was in 

 itself too little advanced. Comparison was impossible, for 

 the standards were not forthcoming. 



Vitalism in its original form gave way to the rapid ad- 

 vance of knowledge as to the correlation of the physical 

 sciences which took place in the forties. Of the. many 

 writers and thinkers who contributed to that result, J. R. 

 Mayer and Helmholtz did so most directly, for the con- 

 tribution of the former to the establishment of the Doctrine 

 of the Conservation of Energy had physiological considera- 

 tions for its point of departure ; and Helmholtz, at the time 

 he wrote the Erhaltung der Kraft, was still a Physiolo- 

 gist. Consequently when Ludwig's celebrated Lehrbuch 



