22 Professor Burdon Sanderson [Jan, 24, 



progress of Physiology by the new interest which it gave to the study, 

 not only of structure and development, 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 comparative 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 

 v/ent on in the living body as they do outside of it ; but when a 

 difSculty arose in so explaining them the Physiologist was ready at 

 once to call in the aid of a " vital forced 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 principles 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 advance 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 contribution of the former to the establishment of 

 the Doctrine of the Conservation of Energy had physiological 

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

 he wrote the " Erlialtung der Kraft," was still a Physiologist. 

 Consequently when Ludwig's celebrated Lehrhuch came out in 

 1852, — the book which gave the coup de grace to vitalism in the old 

 sense of the word, — his method of setting forth the relations of vital 

 phenomena by comparison with their physical or chemical counter- 

 parts, and his assertion that it was the tasv of Physiology to make 

 out their necessary dependence on elementary conditions, although in 

 violent contrast with current doctrine, were in no way surprising 

 to those who were acquainted with the then recent progress of 

 research. Lud wig's teaching was indeed no more than a general 

 application of principles which had already been applied in par- 

 ticular instances. 



The proof of the non-existence of a special " vital force " lies in 

 the demonstration of the adequacy of the known sources of energy in 

 the organism to account for the actual day by day expenditure of 

 heat and work — in other words, on the possibility of setting forth an 

 energy balance sheet, in which the quantity of food which enters the 



