300 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



The total nitrogen excretion may first be considered simply as an 

 index of the excretion of organic material. It can be seen from table 

 39 that with Gul the nitrogen excretion varied considerably from day 

 to day. The maximum amount recorded for this subject on any day 

 was 14.66 grams during the Christmas vacation; the minimum amount 

 was the extraordinarily small quantity of 3.90 grams on December 

 1-2. In the beginning of the experiment there was considerable 

 irregularity in the amount of nitrogen excreted, with a tendency for 

 lower values to obtain subsequent to November 22. Yet there appears 

 to be no definite correlation between the volume of urine, the specific 

 gravity, and the total nitrogen excretion, nor do the other subjects 

 show an approximation to regularity in such relationship. The nitro- 

 gen data for the other subjects will, however, be given in subsequent 

 tables and discussed in that connection. 



The general conclusion, therefore, which may be drawn from the 

 urinary excretion of these subjects is that the reduced diet has a dis- 

 tinct tendency to lower somewhat the volume of urine and likewise 

 a corresponding tendency to increase to some extent the specific 

 gravity. This is more or less to be inferred from the fact that there 

 was no profound alteration in the total amount of nitrogen excreted, 

 and hence the smaller volume of urine was somewhat more con- 

 centrated. Little, if any, satisfactory discussion can be introduced 

 here as to the fact that the lower volumes require somewhat less work 

 of the kidneys, for it may be questioned whether or not the decrease 

 in the work of excretion due to the smaller volumes would not in large 

 part be compensated by the somewhat increased concentration of 

 the urine. In any event the change is not sufficient to consider that 

 this would have a material effect upon the general urinary output of 

 these subjects, so far as specific gravity and the volume of urine are 

 concerned. 



NITROGEN INTAKE AND OUTPUT OF SQUAD A. 



While the statistics for Ckil show no consistently lower output of 

 nitrogen, save perhaps subsequent to November 22, nevertheless even 

 this change was not profound, and it seems advisable to consider how 

 the low diet affected the squad as a whole. It has already been shown 

 that the intake of nitrogen was not in all cases alike. In general, 

 however, the average intake was not far from the same for the entire 

 squad, both in total calories and in total nitrogen. This is shown more 

 in detail in certain other tables.^ 



Although this is not the specific place to discuss the relationship 

 between the intake and output of nitrogen, with special reference to 

 the nitrogen balance, several features of the first 12 days of the experi- 

 ment justify our reproducing here the figures for the total nitrogen 

 in urine for this period and likewise for a period of 12 days from 



>See tables 46 to 58, pp. 312 to 341, 



