SECTION D PHYSIOLOGICAL CHEMISTRY 



(Hall 16, September 22, 3 p. m.) 



CHAIRMAN: PROFESSOR WILBUR O. ATWATER, Wesley an University. 

 SPEAKERS: PROFESSOR O. COHNHEIM, University of Heidelberg. 



PROFESSOR RUSSELL H. CHITTENDEN, Yale University. 

 SECRETARY: DR. C. L. ALSBERG, Harvard University. 



PROBLEMS IN NUTRITION 



BY OTTO COHNHEIM 



(Translated from the German by Prof. J. L. R. Morgan, Columbia University) 



[Otto Cohnheim, Special Professor of Physiology, University of Heidelberg; 

 Assistant Physiological Institute, b. May 30, 1873, Breslau, Germany. Grad- 

 uate Physician, Heidelberg, 1896; M.D. ibid. 1896; Privat-Docent, ibid. 1898; 

 Zoological Station, Naples, 1900-02; Pawlow's Institute, St. Petersburg, 1902. 

 Author of Chemistry of Albuminous Substances; Physiology of Alpinism ; and 

 many articles on biology and physiological chemistry.] 



THE object of the papers read here is not so much the consideration 

 of any one restricted branch of science as it is the discussion of those 

 broader fields which lie between and are intimately connected with 

 several branches of science. In accord with this I propose to speak 

 on a subject belonging primarily to the physiology of nutrition, but 

 one which at the same time has very great politico-economic import- 

 ance. To-day, as the result of the great progress which has been 

 made in the physiology of nutrition, we can in general give a definite 

 answer to the question as to the extent of the agreement between 

 the actually observed dietary of an individual or group of individuals, 

 and the conclusions obtained theoretically. At any rate to-day we can 

 account physiologically for, and regard as physiologically necessary, 

 a whole series of phenomena which in the past could only be accepted 

 as empirical facts. The physiological consideration of race-dietary, 

 on the other hand, will show how it happened that social considera- 

 tions for decades have directed and restricted physiological progress. 



The food of man, as is well known, is composed of proteids, fats, 

 and carbohydrates. In most food-stuffs we have all three classes of 

 substances; only sugar and butter belong solely to one class, the 

 former being a carbohydrate, the latter a fat. The proteids assume 

 a particularly important position owing to the fact that our bodies 

 themselves are composed to a very large extent of proteinaceous 

 material and hence can only be built up by proteids. The major 



