M KM0I11S OF THE NATIONAL ACADEMY OF SCIENCES. 



393 



Table CXXII. — CompQrison of amounts of alcohol consumed and excreted unoxidized in experiments in which itformed a 



part ofth diet. 



VARIATIONS IX DAILY EXCRETION OF NITROGEN. 



In the course of these experiments it has been found very difficult to obtain a uniform 

 excretion of nitrogen in the urine from day to day, even with uniform conditions of food, rest, 

 and work. In studying the effect of alcohol upon nitrogen metabolism these variations should 

 be considered. Table CXXIII shows the daily nitrogen content in the urine in experiments with 

 and without alcohol. It also shows the elimination of nitrogen on the days of the preliminary 

 period which always preceded an experiment in the calorimeter, and during which the subject 

 had very nearly the same diet as in the following experimental period. In many cases the amount 

 of nitrogen in the urine varied greatly from day to day, this variation being especially marked 

 in the preliminary period. This may possibly be due in part to differences in amountsof external 

 muscular work performed on different days, but the general results of experiments on the effects 

 of muscular activity upon nitrogen metabolism imply that when the work is not severe and the 

 supply of energy is sufficient the output of nitrogen is not greatly increased. It seems more 

 probable that the cause may lie in part psychic. We have had occasion to note an increase of 

 nitrogen excretion after mental excitement, and not infrequently such increase has occurred on 

 the day before or the day after the subject entered the respiration chamber for an experiment. 

 This was especially the case with E. O., with whom there was a notable increase in the excretion 

 of nitrogen on the day before entering the chamber in experiments 5, 6, 7, 12, 13, and 11, and on 

 the day after in experiments 10, 11, 15, and 22. Something of the same kind appears with 

 A. W. S. in experiment IS, with the exception that the increase was observed on the second day of 

 the preliminary period, continued for a few days, and, with the exception of a slight rise on the 

 day after entering the calorimeter, greatly decreased in amount during experiments IS to 20. 

 With J. F. S., on the other hand, there was as a rule comparatively little difference in the 

 nitrogen eliminated on different days of the preliminary period, and a very slight, although regular, 

 increase on the day following his entrance into the calorimeter. 



The figures in the last four columns of the table show the average elimination of nitrogen 

 during different periods with and without alcohol as part of the diet. The pronounced difference 

 in some experiments between the elimination of nitrogen in the preliminary period and the calo- 

 rimeter period is of interest as indicating that these unexplained variations are much greater than 

 any which may be brought about by the addition of alcohol to the diet. This is one of the facts 

 which lead us to hesitate to attribute to the alcohol any definite and uniform effect upon the 

 metabolism of nitrogen. 



