292 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



tained to show that fasting does not completely kill the bacterial ac- 

 tion, for Professor KendalP found bacteria in the colon. With the 

 confusion existing at the present time, not only as to a classification 

 of the exact facts known, but more especially with regard to the absence 

 of any logical method of procedure, we must for the present adhere 

 simply to the original plan of considering the nitrogen in the feces as 

 being derived from food, and express our results according to the com- 

 monly accepted method. 



In our digestion experiments we do not consider the digestibility 

 of fat. It should be pointed out here that the common methods for 

 analyzing the feces are wholly unsuited for the proper determination 

 of the digestibility of fats, for the very large proportion of soaps in 

 feces which are insoluble in ether makes a crude ether extract of 

 feces wholly unsuitable for an estimate of the total fat content. In 

 this research we are primarily interested in the question of whether 

 or not there is a profound disturbance in the proportion of nutrients 

 digested, as commonly expressed, when a diet is used which is very 

 low in calories and moderately low in nitrogen. 



DIGESTION EXPERIMENTS WITH SQUAD A ON REDUCED DIET. 



The results of our observations for Squad A are recorded in table 37 

 in grams of nitrogen per day in food and feces and in calories of energy 

 per day in food, feces, and urine. The total and percentage of ni- 

 trogen utilized, and the total and percentage of energy available are 

 also given. The differences in the utihzation of nitrogen between 

 the beginning and end of the experiment are extremely small, rarely 

 amounting to more than 4 per cent. Hence it would be incorrect to 

 state that there was a pronounced relationship between the amount 

 of nitrogen in food and the nitrogen utilized. 



Special attention should be called to the fecal nitrogen. While the 

 character of the diet and the necessity for changing individual diets to 

 maintain weight made it impossible to secure uniformity of nitrogen 

 intake in all instances, we find that on October 8 to 12, the nitrogen 

 in the intake was relatively constant for all men, that is, the values 

 were all between 12 and 12.5 grams. The fecal nitrogen per day for 

 these 12 men was as follows: 1.54, 1.35, 1.56, 1.33, 0.96, 1.22, 1.41, 

 1.22, 1.37, 1.33, 1.21, 1.02 grams, respectively; in other words, there 

 was a maximum variation of 0.60 gram. This means, then, that 

 when the same amount of food and essentially the same combinations 

 of food, with practically the same nitrogen content, passed through 

 12 digestive tracts, the fecal nitrogen varied only from 0.96 to 1.56 

 grams. The period of study was, however, only 4 days. Since this 

 particular test was begun on the fifth day of the restriction in diet, 

 it is hardly probable that we can consider it as more than a normal 



^ Benedict, Carnegie Inst. Wash. Pub. No. 203, 1915, p. 232. 



