383 Influence of Inanition on Metabolism. 



The averages for the different experiments range from 2.687 to 3.802 grams. 

 In the experiments with S. A. B., Nos. 71 and 73 show ratios that are not far 

 from the average for all the experiments. In experiment No. 75 the ratio 

 after the first day increases as the fast progresses and in experiment No. 77 

 there is an unusually high ratio on all days of the experiment. The excretion 

 of non-nitrogenous organic matter is therefore indicated. While no tests were 

 made for pathological constituents other than sugar or albumen (see p. 397) 

 the possible formation of /? oxybutyric acid and similar compounds must not 

 be lost sight of in this connection. (See p. 395.) 



excretion of carbon in the urine. 



There is a considerable amount of carbon excreted in the urine, the total 

 quantity of which, although relatively small when compared with the total 

 excretion of carbon as carbon dioxide from the lungs, is nevertheless sufficiently 

 large to be taken into consideration in obtaining the carbon balance. 



The determination of nitrogen in urine is readily and rapidly made by the 

 Kjeldahl method, but the determination of carbon presents a number of 

 difficulties which render the absolute amount determined much less accurate 

 than the corresponding determinations of nitrogen. Since, however, the amount 

 of carbon excreted in the urine is only a small part of the total carbon elimi- 

 nation of the body, a relatively large error in the determination of carbon in 

 the urine may exist without noticeable effect on the carbon balance. 



Pettenkofer and Voit determined the carbon elimination through the urine 

 for the first fasting day, compared it with the total nitrogen and obtained as 

 a result of three different experiments a ratio of carbon to nitrogen of 0.7. 



In comparing the ratio of carbon to nitrogen obtained by other investigators, 

 the differences in the methods emplo} r ed may explain whatever differences in 

 ratios appear. Munk (7) in determining the carbon in the urine dried 5 or 

 10 cc. of the acidulated urine with powdered copper oxide on the water bath 

 and after mixing the material with coarsely powdered copper oxide, burned it 

 in the combustion tube as usual. Determinations of the urine obtained 

 in the experiment with Cetti were possible on only two days, namely, on the 

 first and fifth fasting days. On the first day, during which 13.55 grams of 

 nitrogen were eliminated, there were 12.63 grams of carbon giving the ratio 

 C : N = 0.9. On the fifth fasting day, there were 14.85 grams of carbon and 

 10.69 grams of nitrogen, the ratio being 1.39. Munk states that in his 

 opinion, the determinations made on the fifth day are too large. 



The determinations of Breithaupt's urine were made very carefully and the 

 ratios obtained are given in table 201, which also includes the results of the 

 more recent experiments on J. A. (9) in which the carbon was determined by 

 the moist combustion process of Kjeldahl. 



80 Zeit. f. Biol. (1866), 2, p. 479. The amount of carbon in the urine for each 

 day was 8.25, 8.05, and 9.30 grams, respectively. 



