484 NUTRITIONAL REQUIREMENTS 



professional f asters. Among bedridden inmates of asylums 

 for the aged and of insane asylums a calory requirement be- 

 low 2000 has often been observed, and individual cases have 

 shown 1400 and less. 4 The really small significance of such 

 figures may perhaps be appreciated by stating that this cor- 

 responds, according to 0. Cohnheim 's estimation, to only 

 one liter of milk, eight lumps of sugar and four wheat-rolls 

 a day. 



Protein Minimum. A question, which because of its 

 economic and hygienic importance has aroused considerable 

 discussion, is what is the smallest amount of protein with 

 which a normal person can actually get along! The dis- 

 tinguished American physiologist, Chittenden, has endeav- 

 ored in an extensive series of experiments to prove that 

 Voit's diet, with its 118 grams of protein and 3000 calories, 

 is much too high ; and that a healthy human being can get 

 on with much less. From Chittenden 's experiments, which 

 were performed on educated persons, volunteers of the 

 military sanitary service and on trained student athletes, the 

 results would show, to the author's mind, a requirement of 

 from 1900 to 2500 calories, about 0.10 to 0.12 protein nitrogen 

 to the kilogram of body weight (i.e., 43 to 53 grams of protein 

 for a body weight of 70 kilograms) to be satisfactory. Chit- 

 tenden came to the conclusion that, without necessarily rais- 

 ing the consumption of non-nitrogenous foods, it is possible 

 to maintain nitrogen equilibrium by amounts of protein fully 

 fifty per cent, less than usually considered necessary. 5 

 O. Cohnheim calls attention to the point that in case of many 

 foodstuffs relatively low in nitrogen, particularly legumes 

 and bread, utilization is distinctly poorer than for substances 

 commonly employed in metabolic studies, and that of the 118 

 grams of crude protein of Voit's meal actually only about 

 100 grams are to be regarded as digestible. The difference 

 between this latter and Chittenden 's results is therefore by 



4 Cf. the instructive collection of data by O. Cohnheim, 1. c. 

 8 Cf. L. B. Mendel, Ergebn. d. Physiol., 11, 499, 1911. 



