71 
(7.14 grams) of subject C. P. H. in experiment No. 399, where a slight 
gain of nitrogen was noted. 
It is true that the above results are not in harmony with those 
observed with the ordinary mixed diet, yet at the same time they are 
not unique. Yoit. Rumpf. and Schumm, and Albu. as already pointed 
out (p. 30), have reported experiments with vegetarians whose average 
daily income of nitrogen was far below the tentative standards but yet 
was found to be sufficient either to just maintain the nitrogen equilib- 
rium or to cause a slight gain. Hirschfeld." Kumagawa, 6 Klemperer, c 
Peschel,** Caspari/ Siven/' Neumann. 5, and others have conducted 
metabolism experiments with subjects on mixed diets furnishing much 
less nitrogen than the commonly accepted standards call for and have 
found that the nitrogen equilibrium can be maintained with -mall 
amounts of protein in the food. 
As regards the experiments quoted, it will be seen that the minimum 
amount of protein necessary to maintain the nitrogen balance varies 
between wide limits. Klemperer reports the minimum amount 33 
grams of daily protein and the writer the maximum $7.9 grams. In 
the former case a gain is noted and in the latter a loss. It thus 
appears that with one subject, weighing 141 pounds. 33 grams protein 
and 5,018 calories were more than sufficient to attain nitrogen equilib 
rium; another subject, A. V.. weighing 150 pounds, with a diet fur- 
nishing S7.9 grams protein and 3.155 calories, suffered a slight loss of 
nitrogen. These findings serve to emphasize the conclusion of Caspari 
that the minimum amount of daily protein required varies with the 
individual and may even vary with the same individual at different 
times. 
It must be remembered that although again of nitrogen was reported 
by Albu when the daily diet supplied only 34 grams protein and 1,400 
calories the subject was a very small woman, weighing but 83 pounds. 
Si ven h brings out one point in his conclusions, in full accord with the 
results of the present investigation and which should serve as a warn- 
ing to anyone contemplating any appreciable decrease in the protein 
of the daily diet, namely, that when the protein of the food is increased 
after the body has suffered a loss of nitrogen, there is at once an effort 
to attain nitrogen equilibrium, and it appears that any gain of nitrog- 
enous body material is a comparatively slow process. This apparently 
indicates that the living substance must be slowly formed from the 
protein furnished by the diet. 
"Arch. Physiol. [Pfluger], 41 (1887), p 533. 
&Arch. Path. Anat. u. Physiol. [Virchow], 116 (1889), p. 370. 
'•Arch. Path. Anat. u. Physiol. [Virchow], 116 (1889), p. 362. 
'Der Eiweissbedarf des gesunden Menschen, Inaug. Diss., Berlin, 1890. 
'Arch. Anat. u. Physiol., Physiol. Abt., 1901, p. 323. 
/Skand. Arch. Physiol., 11 (1901), p. 308. 
?Arch. Hyg., 45 (1*902), p. 1. 
h Skand. Arch. Physiol., 11 (1901), p. 330. 
