412 Influence of Inanition on Metabolism. 



The proportion of the total phosphoric acid excreted in the first twelve 

 hours is, on the average, not far from 57 per cent, although considerable 

 differences, even in the fasting experiments, are found. For example, the 

 variations in experiment No. 73 are from 51.5 to 63.5 per cent. In the food 

 experiments, much larger variations appear, the most noticeable being that 

 on the last day of experiment No. 76, where but 24.1 per cent of the total 

 phosphoric acid was excreted during the period from 7 a. m. to 7 p. m. 



Thus it is seen that, in general, the larger proportion of the phosphorus is 

 excreted in the day period and, indeed, on reference to table 198, it will be 

 noticed that the proportions thus excreted correspond very closely, in general, 

 to the proportions of total nitrogen excreted during this period. 



Ratio of nitrogen to phosphorus in the urine. The disintegration of phos- 

 phorized material in the body during fasting presumably follows the general 

 course of protein katabolism, save for the drafts upon the phosphatic material 

 of the bones, and hence the ratio of nitrogen to phosphorus in the excretion, 

 when compared with the ratio of nitrogen to phosphorus in the various tissues 

 of the body is of interest. According to Munk (7, p. 159) there are about 

 6.8 " parts of nitrogen to each part of phosphorus pentoxide in flesh, and 6.4 

 parts of nitrogen to one of phosphorus pentoxide in the liver. Accordingly it 

 is to be expected that, during fasting, the ratio of nitrogen to phosphorus pent- 

 oxide would be not far from 6.6. Eatios lower than this would indicate a draft 

 upon phosphatic material of low nitrogen content such as bone. 



In experiments with Succi, the ratios were computed by Luciani (4), but 

 for the Florence fast in table 212, given above, the values for total nitrogen as 

 corrected by Munk are used in computing the ratios. The ratio on the first 

 day in the experiment at Florence is 7.87 and there is a general tendency for 

 the ratios to diminish as the fast progresses. In the fast at Naples the ratio is 

 more nearly constant, and the initial ratio, 4.90, is much lower than that of the 

 Florence fast. The Vienna fast shows singularly constant ratios after the first 

 day, the minimum being 4.07 (second fasting day) and the maximum 4.85 

 (sixth fasting day). 



The excretion of so small an amount of phosphorus pentoxide on the tenth 

 day of Cetti's fast resulted in a very high ratio (10.00). Aside from this day, 

 the average ratio for the nine days of fasting is 4.4. In the other fasts the 

 ratio is in practically all cases much below 6.6. 



The peculiarity in the ratios for the sixth and seventh days of the fast of 

 Flora Tosca may possibly be explained by the fact that on the sixth day the 

 subject defecated after taking an aperient, while on the seventh she had 

 considerable muscular exercise. 



"Forster, Zeit. f. Biol. (1873), 9, p. 363, and ibid. (1876), 12, p. 466, gives the 

 relation between the total nitrogen and phosphoric anhydride in dog flesh as 7.2. 



