404 ISIDOR GKEENWALD 



Army was sent to New Haven as subjects for Chittenden's experiments. 

 The observations upon them differed from those upon the students and of- 

 ficers of the university in that the diet was prescribed. After about two 

 weeks upon their accustomed rations, the food was selected by Chittenden 

 to contain less protein and to furnish a rather smaller amount of energy, 

 while retaining approximately the same bulk and furnishing considerable 

 variety. Per kilo of body weight, the average" daily urinary nitrogen, 

 over a period averaging 144 days varied from 0.106 to 0.148 gram, the 

 average of all being 0.128 per kilo or 7.89 grams per individual. The 

 weight of the men remained nearly constant, some gained a little, others 

 lost, but the losses were advantageous rather than otherwise. The men were 

 regularly engaged in drill and other exercises and improved progressively 

 in muscular strength and general physical condition during the whole of 

 their stay in New Haven. 



These observations were confirmed by three metabolism experiments, 

 In the first, of six days' duration, each man's food contained a daily aver- 

 age of from 7.71 to 8.23 grams nitrogen, or from 0.111 to 0.153, averaging 

 0.135 gram, per kilo and furnished approximately 2078 calories, or 33 per 

 kilo. In all cases the excretion of nitrogen in the urine and feces was 

 greater than the intake in the food. Six weeks later, a second experi- 

 ment of seven days was begun. The food now furnished 2509 calories 

 or 40.4 per kilo and contained from 9.27 to 9.64 grams nitrogen, or from 

 0.128 to 0.180, average 0.157, grams per kilo. Upon this diet, all the men 

 but one gained nitrogen, the average retention being 0.591 gram per ma.n 

 per day. A third experiment of five days came a month later. The 

 energy content of the food was approximately 2840 calories or 45.9 per 

 kilo and it contained from 8.14 to 8.67 grams nitrogen, or from 0.112 to 

 0.157, average 0.139, gram per kilo. Three men retained nitrogen and 

 eight men lost, the average of all being a daily loss of 0.254 gram per man 

 per day. 



Since these losses occurred in spite of the fact that the diet furnished 

 300 calories per man, or 5 per kilo, more than that employed in the previ- 

 ous experiment, it would seem that the nitrogen of the food had been re- 

 duced to too low a level. The apparent nitrogen retention in the sec- 

 ond experiment, 0.591 gram per man per day, is probably not much, if 

 at all, greater than would be accounted for by the perspiration in men en- 

 gaged in as much exercise as was taken by these subjects. We may there- 

 fore conclude that the least adequate nitrogen intake demonstrated by those 

 experiments upon soldiers to be 9.5 grams, equivalent to about 60 grams of 

 protein per day. Calculated to 70 kilos, it would be 69 grams. Similarly, 

 the energy content would be 2800 calories. These values are very nearly 

 the same as those obtained from the experiments upon athletes. 



Although some of the food served was not eaten, the entire detail 

 received practically the same diet. Nevertheless, as Benedict(&) (1906) 



