URINE. 



303 



here 12 men, each of whom took practically the same daily amount of 

 nitrogen as the others for a period of approximately 10 days, and yet 

 the nitrogen excretion varied somewhat widely for the corresponding 

 days. Thus, on October 9 Pea and Tom, with essentially the same 

 nitrogen intake, i. e., 12.21 and 12.05 grams, respectively, have a 

 nitrogen output in the urine of 15.53 grams for Pea and 10.73 grams 

 for Tom. The striking fall in the nitrogen intake for the whole squad 

 on October 4, amounting to over 60 grams, was accompanied by a fall 

 of 16 grams in the total nitrogen in the output. On the whole the 

 nitrogen output for the 12 days is reasonably constant, although the 

 nitrogen intake was greatly decreased after the first 3 days for which 

 we have a record of the food. 



Another point which should be brought out- is the fact that the 

 nitrogen of the intake was by no means definitely fixed each day, but 

 depended somewhat upon the character of the food served generally 

 to the men. Thus, we find a marked rise from an average of 9.33 

 grams on October 7 to 13.82 grams on October 8. This is a good 

 illustration of the lack of positive control of nitrogen intake; in other 

 words, the nitrogen intake was not predetermined. 



If we examine the nitrogen excretion in the 12 days from December 

 5 to December 18 (table 43) we note again rather striking irregulari- 

 ties, which are even greater than those noted for the October excre- 

 tion, minimum figures of about 6 grams appearing in several in- 

 stances. On the other hand, we have but to examine the nitrogen 

 intake on the corresponding dates (see table 42) to find somewhat wide 

 variations, which may, in part, account for some of the variations in 

 the nitrogen in the urine. These two sets of tables, however, give a 

 fairly good picture of the differences in nitrogen intake and nitrogen 

 excretion observed with Squad A prior to the reduction in the diet 

 and again at the lower level when they had approximately a main- 

 tenance diet. 



Disregarding the individual variations found on the different days 

 and taking the averages for the group, we may consider the total 

 nitrogen excretion per man per 24 hours as illustrated in these specimen 

 tables. On the first 12 days of the experiment, that is, from September 

 28 to October 10, inclusive, we find the average nitrogen excretion to 

 be 12.19 grams of nitrogen per day (see table 41). The averages for 

 the individual days do not vary widely from this total average, the 

 highest daily average being 13.15 grams on October 3 and the lowest 

 average, singularly enough on September 29, 10.53 grams, this being 

 the last day on which the diet was uncontrolled, for the feeding at the 

 diet table was not begun until the morning of October 1. Taken as a 

 squad, therefore, the urinary excretion is surprisingly uniform. 



The average daily excretion of nitrogen for the squad in the later 

 period of the experiment, namely, from December 5 to December 



