PRESENT PROBLEMS 343 



adrenals, the epinephrin? Where is there a more active agent in mod- 

 ifying the nutritional processes of the body than the iodine-containing 

 constituent of the thyroid, the iodothyrin? These may truly be 

 counted as representing a type of substances manufactured or se- 

 creted primarily for the physiological effect they are capable of exert- 

 ing; but what about the host of other substances present in the body, 

 many of them simple products of katabolism? May they not have 

 some marked physiological property that if known would serve as a 

 sufficient excuse for their formation? Or, may they not possess some 

 hidden or obscure property which if once understood would make 

 clear a secondary or subsidiary function of no small import for the 

 maintenance of physiological equilibrium, or for the w r elfare of the 

 body? Many suggestions and some facts present themselves illustrat- 

 ing how direct and indirect influences may be exerted, all pointing 

 toward the harmonious action and interdependence in function of 

 many of the substances formed in the body. Some, however, un- 

 doubtedly have more or less of a toxic action, especially when formed 

 in excessive or undue amounts. Thus, the alloxuric bases seemingly 

 cause fever when injected into the circulation or taken per os, 1 and 

 according to the recent observations of Mandel 2 there is a very 

 striking relationship between the quantity of alloxuric bases elimin- 

 ated in the urine and the temperature of the body in cases of aseptic 

 fevers, indicating that these substances, with possibly other incom- 

 plete products of tissue-metabolism, are important factors in the pro- 

 duction of febrile temperature. We may confidently expect that a 

 thorough study of the physiological action of all the varied katabolic 

 products formed in the body will result in a decided expansion of our 

 knowledge regarding the part these substances may play in normal 

 and abnormal metabolism, and in nutrition in general. 



Just here, reference may be made to the many problems in the 

 broad field of nutrition that confront the physiological chemist of the 

 present day. The maintenance of life on a sound physiological basis is 

 one of the practical problems in physiological chemistry, and its solu- 

 tion is not yet attained. We need fuller knowledge regarding the part 

 played by the different nitrogenous food-stuffs, the relative physio- 

 logical value of animal and vegetable proteid, the relative value of 

 fats and carbohydrates as nutrients aside from their different calorific 

 power, and, by no means least, a fuller and more accurate knowledge of 

 the true physiological needs of the body for proteid foods. Our pre- 

 sent dietetic standards are absolutely false and valueless. Our present 

 conception of the physiological needs of the body is altogether faulty 

 and distorted. Our ideas of the rate and extent of proteid metabol- 



1 See Burian and Schur, Archiv fur die gesammte Physiologic, Band 87, p. 239. 

 1 The Alloxuric Bases in Aseptic Fevers, Amer. Journal of Physiology, vol. 10, 

 p. 452. 



