PHOSPHATES. 723 



day. A small part of the phosphoric acid of the urine originates from the 

 burning of organic compounds, such as nuclein, protagon, and lecithin, 

 within the organism ; on exclusive feeding with substances rich in nuclein 

 or pseudonuclein the quantity of phosphates is essentially increased; 

 still it is undecided to what extent the excretion of phosphoric acid is 

 a measure of the absorption and decomposition of these bodies. 1 The 

 greater part originates from the phosphates of the food, and the quantity 

 of phosphoric acid eliminated is greater when the food is rich in alkali 

 phosphates in proportion to the quantity of lime and magnesium phos- 

 phates. If the food contains much lime and magnesia, large quantities 

 of earthy phosphates are eliminated by the excrement; and even though 

 the food contains considerable amounts of phosphoric acid in these cases, 

 the quantity excreted by the urine is small. This is especially true of 

 herbivora, in which the kidneys are the chief organs for the excretion 

 of alkali phosphates. In man, according to EHRSTROM, the content 

 of lime in the food seems to play no important role, as in his experiments 

 about one-half of the phosphoric acid taken as CaHPO 4 was absorbed; 

 still the extent of phosphoric-acid excretion through the urine depends 

 in man not only upon the total quantity of phosphoric acid in the food, 

 but also upon the relative amounts of the alkaline earths and the alkali 

 salts of the food. In carnivora, in which phosphate injected subcutane- 

 ously is eliminated by the intestine (BERGMANN), the urine is habitually 

 poor in phosphates. 2 



As the extent of the elimination of phosphoric acid is mostly dependent 

 upon the character of the food and the absorption of the phosphates in 

 the intestine, it is apparent that the relation between the nitrogen and 

 phosphoric-acid excretion cannot run parallel. This is in fact so, and, 

 according to EHRSTROM, the organism has the power of accumulating 

 large quantities of phosphorus for a relatively long time independent of 

 the condition of the nitrogen balance. With a certain regular food the 

 relation between nitrogen and phosphoric acid in the urine can be 

 kept almost constant. Thus on feeding with an exclusive meat diet, 

 as observed by VoiT 3 in dogs, when the nitrogen and phosphoric acid 

 (P 2 O-) of the food exactly reappeared in the urine and feces, the relation 

 was 8.1:1. In starvation, as shown by the compilation of R. TIGER- 

 STEDT, 4 the phosphorized constituents of the body are destroyed to a 



'See A. Gumlich, Zeitschr. f. physiol. Chem., 18; Roos, ibid., 21; Weintraud, 

 Arch. f. (Anat. u.) Physiol., 1895; Milroy and Malcolm, Journ. of Physiol., 23; Rohmann 

 and Steinitz, Pfliiger's Arch., 72; Loewi, Arch. f. exp. Path. u. Pharm., 44 and 45. 



2 Ehrstrom, Skand. Arch. f. Physiol., 14; Bergmann, Arch. f. exp. Path. u. Pharm., 

 47. 



3 Physiologic des allgemeinen Stoffwechsels und der Ernahrung in L. Hermann's 

 Handbuch, 6, Thl. 1, 79. 



4 Skand. Arch. f. Physiol., 16. 



