NITROGEN BALANCE. 309 



output remained with singular persistency over 9.5 grams, there being 

 but one exception. Kim, with the relatively low average body-weight 

 of 61 kilograms, showed an average nitrogen excretion of 9.2 grams. 

 Since all these men had practically the same nitrogen intake of not far 

 from 8 grams (for no fluctuation in the nitrogen intake appeared in this 

 short period which was at all comparable to the variations in nitrogen 

 intake found with Squad A) the consistency and uniformity in nitrogen 

 excretion are all the more remarkable and point inunediately toward a 

 very considerable nitrogen loss, which will be subsequently discussed. 

 The wholly remarkable consistency of nitrogen excretion in the urine, 

 irrespective of the nitrogen ingested, explains largely the singularly 

 anomalous fact that the nitrogen excretion of the subjects in Squad A 

 on the Mondays following the free Sundays was not materially af- 

 fected by the relatively large nitrogen intake on these days. The two 

 subjects in Squad A, Gul and Pec, who collected the urine during 

 the Christmas recess, showed relatively little change in the nitrogen 

 output as compared with their probable nitrogen intake. See tables 

 51a and 55a, pages 325 and 336. The uniformity of nitrogen excretion 

 with extraordinarily large changes in nitrogen intake in the food is a 

 point worthy of special emphasis. 



THE NITROGEN BALANCE. 



It was hoped that in this study both the nitrogen intake and the 

 nitrogen output could be sufficiently controlled throughout the entire 

 time so that a complete nitrogen balance could be obtained and at 

 the end of the experimental period the exact nitrogen loss to the body 

 could be determined in addition to the changes in body-weight. It 

 was psychologically undesirable to restrict the men at every meal, 

 and free days were thus occasionally permitted, with, however, certain 

 suggestions as to restrictions which it was believed the men would more 

 or less heed. As shown on page 270 (table 34), on the uncontrolled 

 Sundays the food taken by the men contained much larger amounts 

 of energy than they ordinarily consumed, often more than twice the 

 amount, but the nitrogen intake was by no means so large propor- 

 tionately. There were, of course, occasional exceptions, such as the 

 28.47 grams of nitrogen taken on January 13 by Kon and Gul, and 32.7 

 grams by Moy. But on the average the squad consumed on these 

 uncontrolled days 16.62 grams of nitrogen, a value 50 per cent higher 

 than that indicated for the average intake per man per day during the 

 whole experimental period (10 grams). In addition to these uncon- 

 trolled Sundays we have likewise four days at the Thanksgiving 

 recess of uncontrolled period and also a somewhat lengthy period of 18 

 days at Christmas time. These breaks were simply unavoidable. 



Aside from these uncontrolled periods, the nitrogen in the food was 

 determined every day. The urine was also collected with remarkable 



