1906.] on Some Dietetic Problems. 273 



tion ; hence if nitrogenous equilibrium is to be attained more proteid 

 must be taken than is the equivalent of the nitrogen output of 

 fasting. 



The question for practical dietitians, however, was not what is 

 the proteid minimum, but what is the proteid optimum ? This ques- 

 tion could only be solved empirically by observation of the amount of 

 proteid actually consumed by persons in nitrogenous equilibrium. 

 From such observations Voit had fixed the proteid optimum at 

 118 grms. daily. The lecturer then described the experiments of 

 Chittenden, which seemed to show that health could be maintained 

 on a much lower amount than this, even on as little as 60 grms. 

 Did Nature furnish no hint as to the correct standard ? It was 

 suggested that in the proportion of proteid in human milk such guid- 

 ance might be found. Assuming that an infant of six months con- 

 sumed milk to the value of 578 calories daily, containing 14 grms. of 

 proteid, and that the average energy-value of an adult diet was 3000 

 calories, it followed that if the adult was to take in the same propor- 

 tion of his energy in the form of proteid as the child does, the 

 standard for the adult would be about 74 grms. of proteid, it being 

 further assumed that growth in the child might be set off against the 

 greater wear and tear in the adult. The results of this method of 

 attacking the problem were in striking harmony with those arrived 

 at empirically by Chittenden. 



The lecturer then touched upon the relative advantages and dis- 

 advantages of a low nitrogenous intake, emphasising the possible 

 value of a proteid-rich diet in increasing the powers of resistance to 

 infective disease, especially tuberculosis, and the danger of having no 

 margin of circulating proteid to draw upon in case of emergency. 



Summing up the reply to the second problem it was shown that 

 the proteid optimum must vary greatly in different circumstances and 

 individuals, and in accordance with the composition of the diet as a 

 whole, but that it probably stood nearer to the proteid minimum than 

 had hitherto been supposed. The old and new dietary standards were 

 then contrasted as regards both energy and proteid, and in conclusion 

 the bearings of an acceptance of the new standard upon such prac- 

 tical systems of diet as vegetarianism were briefly indicated. 



[R. H.] 



Vol. XVIII. (No. 100) 



