Nitrogen in Urine. 371 



experiment No. 75, the average for the 5 experiments being 0.192 gram. 

 On the fifth, sixth, and seventh clays, the average excretion per kilo of body- 

 weight is 0.186, 0.190, and 0.181 gram, respectively. 



The same differences that exist in the total excretion of nitrogen in the 

 different experiments on the first day of the fast likewise appear in the excretion 

 per kilo of body-weight. On the second and succeeding days, the excretion 

 per kilo of body-weight is on an average much more nearly constant, and the 

 maximum is reached on the third day. 



In discussing the possible causes of variations in the elimination of nitrogen 

 with different subjects, and indeed, in different experiments with the same 

 subject, certain questions other than that as to the nitrogenous excretion on the 

 day before the fast may be raised. For example, does the relative amount of 

 protein in the body influence the rapidity with which it is disintegrated during 

 the fast? In discussing the experiments on Cetti and Breithaupt, the Berlin 

 investigators were of the opinion that the large increase in the elimination of 

 nitrogen by these two subjects was due to the fact that they were not very fat 

 and hence had a larger proportion of protein in the body. With the subject 

 S. A. B., considerable light may be thrown upon the storage of protein inasmuch 

 as between experiments Nos. 76 and 77 and also for a period of two weeks after 

 experiment No. 77, a careful record was kept of all food ingested and the 

 nitrogen was determined for each day's food, urine, and feces thus furnishing 

 a complete balance of income and outgo of nitrogen. The details of these 

 balances are reported beyond (see page 534), but it may be stated here that 

 the results show that during the period between experiments Nos. 76 and 77, 

 the subject actually gained 45.0 grams of nitrogen more than were lost during 

 fasting experiment No. 75 and food experiment No. 76, thus indicating a 

 marked storage of nitrogen in the body. 



In the period following experiment No. 77 the data show that the body 

 gained in addition to the nitrogen lost during the fast 11.1 grams of nitrogen. 



Under these conditions, the increased amount of nitrogen is very noticeable 

 and hence we should expect to find, that if the actual amount of nitrogenous 

 material present in the body, be it either " organized " or " circulating," at the 

 beginning of the experiment influences the subsequent nitrogen elimination 

 during fasting, there would be an increase in the nitrogen elimination in 

 the last experiment with this subject (experiment No. 77) over that excreted 

 in the earlier ones. As a matter of fact, aside from the unusually low excretion 

 noted on the first day of experiment No. 71, the absolute excretion, as well as 

 the excretion per kilo of body-weight, was lowest rather than highest in 

 experiment No. 77. 



Unquestionably the gain in body-weight after fasting was due in large 

 measure to the replacement of the water lost, but there must have been a not 

 inconsiderable gain of fat, since the subject weighed considerably more at the 

 end of the series of experiments than at the beginning. It may then be true 



