I'll! NCI I'M. FKKMlNi; PKHIOD. 41 



nitro'/en and phosphoric acid of the food exactly reappeared in the 

 urine and the t'eees. the relationship was S.I :1. In these experiments 

 with rabbits the nitrogen and phosphoric acid ratio in the urine varied 

 from 4.C>:1 to 7.7:1. In starvation Wellmann" has shown that this 

 relationship is chanired, namely, relatively more phosphoric acid is 

 eliminated, which seems to indicate that besides flesh and related 

 tissues, aUo another tissue rich in phosphorus is largely destroyed. 

 The starvation experiments show that this is the bone tissue. Tiger- 

 stedt'' claims that only 0.1. 'II gr:,m of phosphoric acid is eliminated 

 in the feces of man daily. For some years it was claimed by many 

 investigators that the elimination of phosphorus and nitrogen should 

 run |>arallel. both substances heini: derived from protein, the usual 

 ratio of nitrogen to phosphorus helm: 7.5:1, In these experiments 

 there U a general tendency in the individual data toward parallelism 

 between the nitrogen and phosphoric acid excretion in the urine, but 

 this ratio U not maintained in the general average, as in the case of 

 the rabbit> fed inorganic pho^phom> a much larger proportion of the 

 phosphoric acid is ah-orhed and eliminated by the kidneys. Siven. 1 ' 

 Khrst roin.'' and Me\ei have also shown no parallelism to exi-t. 

 I > ho>j)!nrus i- u-cd in the formation of the bones and other bodies 

 where no nitrogen is pn-ent. Moreover, the ratio of nitrogen and 

 phos|)horic acid will ^'inctimes run a> low as 3:1. 



The amount of phosphoric acid which was fed to all the rabbits \\as 

 considerably lusher than the amount present in their normal diet. 

 In fact, the food itself contained praetieally a .siiHicient amount to 

 supply the needs of the s\Mem. The result is that by adding all 

 excess of phosphoric acid metabolic changes \\ere induced in all 

 Casefl 1" a greater OI le-s extent, The amount of phosphoric acid fed 

 per se\en-da\ period per 1 .01 ill grains of body \\eight varied from 

 ram- in rabbit No. '_' to -J.l grains in the cases of rabbits N'os. 1 

 and :>. The amount of absorbed phosphorus pel 1 1 ,000 grains of body 

 \\eiirht \\as ju-aet ieall\ eipial. 1 .-'I L r ram-. exce|)t inir in the case of rabbit 

 No. _'. \\l-.ei-e the l'n:uies sho\\ O.7 L r ram of phosphoric acid per 1,000 

 grains of body \\ciL r ht. The ratio of phosphoric acid in the urine to 

 that in the fece- >ho\\s that the individual eh-nient was the most 

 important factor, rabbit No. 1 eliminating a far larger proportional 

 amount by tlie kidneys than in the case of any other rabbit. The 

 percentage of phosphoric acid eliminated by the kidneys was higher 

 in the rabbits fed inorganic phosphoric acid than in rabbit No. 1, but 

 this simply means that more of the inorganic phosphoric acid passed 

 through the kidneys unaltered, for rabbit No. 1 retained a larger 

 proportion of it- absorbed phosphorus than did either No. 3 or No. 4. 



-h. gesam. Physiol., 1908, J^:508. <* Ibid., 190:*, / ; 82, 

 ft Skan.l. An h. Physiol., 1904, It; * Zts. phyeiol. Chem., 1904-5, 43 : 1. 



., 1901, 11:30S. 



