410 Influence of Inanition on Metabolism. 



urine, which are not determined by titration with uranium salts. On the other 

 hand, LeClerc and Dubois " 9 were unable to detect measurable amounts of such 

 organic phosphorus. 



In the Middletown experiments gravimetric determinations of phosphorus 

 were made in the daily composite samples, while the determinations by titration 

 with uranium acetate were made on the different periods as well as the 

 composite samples for the day. Obviously, the sum of the amounts of phos- 

 phorus found in the different periods should agree with that found in the 

 composite sample. The determinations made in this way serve two purposes 

 they give an idea as to the proportional distribution of the excretion of 

 phosphorus over the 24 hours, and they furnish a check on the samples for the 

 daily composite and the periods. 



If the results obtained by the titration method are to be taken as representing 

 the amount of phosphorus excreted in the urine of any given period, it is 

 important that the absence of organic phosphorus in the urine be clearly proved 

 as otherwise the results by titration have little value. Consequently, the com- 

 posite sample for each day's urine was concentrated and ignited with sodium 

 peroxide, and the phosphoric acid determined gravimetrically. The amount of 

 phosphoric acid thus found in a total day's urine was compared with the 

 amount found by titration, the results being recorded in the statistical tables 

 along with the weight, composition, and heat of combustion of urine. An in- 

 spection of these tables shows that, in general, the amount of phosphoric acid 

 as found by titration was a trifle larger, if anything, than that found by fusion, 

 which is contrary to what would be expected if organic phosphorus was present. 

 It might further be properly contended that the very fact that the titration 

 method gives on the whole a larger amount of phosphorus than the fusion 

 method is of itself evidence that the titration method as carried out in these 

 experiments is not sufficiently accurate to detect the presence of the small 

 amounts of organic phosphorus usually found. Furthermore, Keller, whose 

 experiment on himself is of especial interest here since it was made on a fast- 

 ing man (4 days), found amounts of organically combined phosphorus pentox- 

 ide amounting to 0.017, 0.0294, 0.0344, and 0.0573 gram, respectively. The 

 increased organic phosphorus elimination as the fast progressed is, according to 

 Keller, of especial significance in interpreting the role of organic phosphorus 

 in metabolism. 



In the light of the experience of Folin and LeClerc & Dubois, it seems hardly 

 probable that any appreciable amounts of organic phosphorus occur in the 

 urine, and at least in the experiments here reported, the titration with uranium 

 acetate may be taken as a measure of the total phosphorus. 



Periodic distribution of phosphorus. By means of the simple titrations 

 with uranium acetate, determinations of phosphorus in the samples of urine 



80 Journ. Amer. Chem. Soc. (1904), 26, p. 1112. 



