NITROGEN BALANCE. 



355 



tion of nitrogen of our subjects is unfortunately scanty, but table 45 

 shows that the nitrogen excretion of a group of men on February 11 to 

 16, 1918, with normal unrestricted diet, averaged 13.97 grams. 



Table 73. — Average daily nitrogen excretion at low weight-level — Squad A. 



NITROGEN OUTPUT OF MEDICAL STUDENTS. 

 Subsidiary evidence regarding the normal nitrogen excretion is sup- 

 plied by the average excretion of nitrogen found with the class in phy- 

 siology in the Harvard Medical School for a number of years past. In 

 the absence of Professor Walter B. Cannon, we must rely upon lecture 

 notes kindly placed at our disposal by Dr. T. M. Carpenter. From 

 analyses of the urinary output of these groups of 40 or more medical 

 students, collected for three successive days, in the years 1909 to 1915, 

 inclusive, the following average values per man per day were obtained : 

 13.8, 12.0, 12.7, 13.3, 12.7, 12.2, and 12.2 grams of nitrogen excreted. 

 These values are distinctly lower than one would expect when it is 

 considered that the American is commonly beheved to Uve upon the 

 so-called Voit protein standard. The low values found by us with the 

 Y. M. C. A. College students might perhaps be ascribed to the strong 

 tendency at the present time to conserve on meat products, and inci- 

 dentally on protein foods, the physiological thought in this case being 

 undoubtedly profoundly influenced by the experiments of Professor 

 Chittenden. On the other hand, the fact that the students at the 

 Harvard Medical School have shown these low values since 1909 indi- 

 cates that the earUer estimates of the American excretion of nitrogen 

 must have been high. The values we find, therefore, are not sur- 

 prisingly low, and this subsidiary evidence obtained with the medical 

 students confirms our behef that the normal nitrogen excretion of the 

 Y. M. C. A. College undergraduate is not far from 13 to 14 grams. 

 The excessive physical exercise and probably larger amounts of food 

 eaten by the students of the Springfield college, as compared with the 

 students of the Harvard Medical School, would normally account for 

 the shghtly higher nitrogen output and protein level at which they were 

 living. 



