A NORMAL DIET 



405 



pointed out, there was a great variation in the amount of nitrogen in the 

 feces of the different men, a variation which does not appear to have been 

 observed in other experiments upon men receiving identical diets. Dur- 

 ing the first period the ratio of fecal nitrogen to food nitrogen varied 

 from 9.06 to 24.6, average 18.0 per cent ; in the second, from 10.7 to 24.4, 

 average 17.6, per cent; and in the third, from 18.9 to 27, average 24.2, 

 per cent. It varied in the same man in the different experiments. Bene- 

 dict regarded these variations as evidences of a possible disturbance of 

 the mechanism of absorption. But the variations in the case of the sol- 

 diers were greater than were observed with the professional men (from 

 10.9 to 19.0, average 15.1 per cent) or with the athletes (13.3 to 21.4, 

 average 16.2 per cent) although the diets within these groups were not uni- 

 form. It seems to the writer that the irregular, and high, values for the 

 nitrogen in the feces of the soldiers may have been due to the ingestion of 

 additional food. That the men should sometimes have "broken diet" seems 

 quite likely. If they did, they would have been likely to attempt to conceal 

 their action by failing to collect all the urine or feces. At any rate, varia- 

 tions in the excretion of nitrogen in the urine such as were recorded in 

 many instances and some of which are included in the following summary 

 of the urinary nitrogen excretion on the last four days of the second balance 

 experiment appear inexplicable except as a result of intentional, or acci- 

 dental, failure to collect all the urine. 



NITROGEN EXCRETED IN THE URINE OF 



Intake the same for each man, except as follows: 1. 8.555; 2. 9.30; 3. 11.107; 

 4. 10.024; 5. 10.392; 6. 10.654; 7. 10.886; 8. 10.215; 9. 8.164; 10. 8.164; 11. 10.475. 



However, in spite of all the objections to some of the details, there can 

 be no question but that Chittenden's results did show that it was possible 

 for men to maintain themselves in good health and with a gain, rather 

 than any demonstrable loss, in physical and mental vigor for a considerable 

 period of time on diets containing less protein than had previously been 

 considered necessary. 



Fisher. Chittenden's observations were extended by Fisher in his 

 studies of the effect of diet upon endurance. It was found that students on 

 a low protein diet, yielding only a moderate supply of energy, less than 

 these students had been in the habit of obtaining, regularly increased in 



