DIGESTIBLE NUTRIENTS IN FOOD MATERIALS. 199 
PROPORTIONS OF DIGESTIBLE NUTRIENTS IN 
FOOD MATERIALS. 

BYEW sO. A UW ALIORS 

In all of the statements concerning the composition of food 
materials and estimates of the proportions of nutrients in 
dietaries and dietary standards published by the Station before 
the present Report, the total rather than the digestible nutri- 
ents have been considered. ‘This usage has been followed in 
the publications of the Office of Experiment Stations, and by 
writers and teachers generally. The reason for not making 
the statements and calculations in terms of digestible nutrients 
has been a very simple one. The data regarding the digesti- 
bility of food materials as they are ordinarily eaten have been 
hardly sufficient to warrant going beyond the use of the total 
nutrients. The usage of chemists and physiologists in Hurope 
has been practically the same as in this country, and for the 
same reason. 
Tentative efforts have, nevertheless, been made toward the 
putting of the estimates of the nutritive values of foods and 
the standards for dietaries upon the basis of digestible nutrients. 
Thus Voit,* in 1882, using the results of Rubner’s experi- 
ments on the digestion of food materials by men, has esti- 
mated the quantities of digestible nutrients corresponding to 
the total nutrients in his well-known standard for the daily 
dietary of an average man at moderate muscular work. His 
figures, as modified by Konig in 1889,f are: 
Carbo- 
Protein. Frat. -hydrates. 
otals s- = = a = - eB Hiat #o: 56 500 
Digestible, - - - = - - 106 53 450 
In like manner Von Rechendorff, in studies of dietaries of 
hand weavers in Zittau, Saxony, published in 1890,{ has made 
detailed calculations of the proportions of both total and 
* “ Physiologie des Allgemeinen Stoffwechsels und der Ernahrung.”’ 
+ ‘Chemie der menschlichen Nahrungs und Genussmittel.”” Third edition, I., 154. 
t Bulletin No. 21, Office of Experiment Stations, United States Department of Agri- 
culture, On Methods and Results of Investigations with Chemistry and Economy of 
Food, p. 163. 
