14 APPLIED PHYSIOLOGY 



tively, we have no clear physiological data to guide us. 

 So far as the tissues are concerned, indeed, the physio- 

 logical teaching appears to be that it is largely a matter 

 of indifference, but that, for the sake of the digestive 

 organs, it is best to derive our energy, not from one or 

 other exclusively, but in some measure from both. From 

 a medical point of view, however, it is not so certain 

 that fats and carbohydrates can replace each other in 

 the diet with indifference. Kickets, for example, is a 

 condition which seems to result from the consumption 

 of a disproportionate amount of carbohydrate and too 

 little fat. There is reason to believe, too, that a diet 

 which contains an excess of carbohydrates may pre- 

 dispose to diabetes by straining the sugar-assimilating 

 functions. On the other hand, when diabetes is once 

 developed, we are compelled to supply the greater part 

 of the patient's energy in the form of fat. 



Meanwhile it may be assumed that 50 grammes of 

 fat and 500 grammes of carbohydrate represent the 

 accepted standard for each ingredient; but it must be 

 borne in mind that these are capable of replacing each 

 other to a large extent, in accordance with the digestive 

 peculiarities of the individual and the opportunities he 

 has of obtaining a supply of each ingredient. 



The following balance-sheet, the expenditure side of 

 which is derived from observation of an actual case by 

 Von Noorden, whilst the income is approximately that 

 of the Chittenden standard, will serve to show in a 

 concise form the practical application of the study of 

 metabolism from its quantitative side. It exhibits a 

 surplus of income over expenditure, and it is assumed 



