THE NEW PHYSIOLOGY. 71 



living structural substance into the balance, and in this 

 last desperate effort to maintain the normal metabolism 

 the nitrogenous oxidation again rises to an amount which 

 for a short time compensates for the energy previously 

 yielded by fat. When death from starvation at length 

 comes, the old flag the flag of life is still flying. 



The massive work of Atwater and his pupils on human 

 nutrition, in which it was shown that the normal daily 

 food requirement of a man is about 3500 calories in 

 energy value, was of course a direct extension of the idea 

 of normal nutrition. We maintain an energy con- 

 sumption of about 3500 calories, just as we maintain 

 about 5-6 per cent, of CO 2 in our alveolar air, or haemo- 

 globin of 18-5 per cent, oxygen capacity in our blood, 

 or legs of a certain length and anatomical structure. By 

 a strange confusion of ideas, the idea is abroad that 

 nutrition is a matter of simple chemistry and physics, 

 and that when we estimate food values in calories, we 

 are exemplifying this fact. This is enough to make 

 staunch old vitalists like Harvey or Johannes Miiller 

 turn round in their graves and laugh. What is it in the 

 body that measures out or withdraws protein, carbo- 

 hydrate and fat with meticulous accuracy in terms of 

 their energy value, in such amount as to maintain the 

 normal energy metabolism ? Is it not the vital spirit 

 or vital force ? the old physiologists would ask. Is not 

 this phenomena of a piece with all the other distinctive 

 phenomena of life, and ought not physiology to face 

 these phenomena fairly and squarely and generalise 

 from them, not run away from them ? This is the ques- 

 tion I am trying to put to you now. 



Now I wish to make it clear that it is not vitalism, 



