PRINCIPAL 1T.KIMN : PERIOD. 

 I'liosIMlolM S BALANCES. 



37 



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In all cases, excepting rabbit No. :5, the average amount of phos- 

 phoric acid ingested during seven days per 1,000 grams of body 

 weight varied from !.<> to 1.7 grains; in No. 3 the amount was 2.2 

 grams. More phosphorus was eliminated by rabbit No. 4 through 

 the kidneys than in any other ease. Both of the rabbits fed organic 

 phosphorus and No. 3 fed inorganic phosphorus retained about the 

 same amounts of the absorbed plnphorus (averaging 53 per cent), 

 while the figure for Xo. 4 is much lower, only 42 per cent. From 

 the average figures, it appears that the rabbits fed organic phos- 

 phorus eliminated a smaller percentage of the ingested phosphoric 

 arid in the urine than those fed on inorganic phosphorus/ It must 

 be remembered that the amount of phosphoric acid eliminated by 

 the kidneys dors not necessarily represent the amount melaholi/ed, 

 fur inorganic phosphorus ingested might and undoubtedly does pass 

 through the kidneys \\ithoiit undergoing any change. Of the total 

 phosphoric acid inge>ted. '>- percent \\ a> found in the feces of No. 1 

 and :il per cent in the feces of No. \, \\hile No. 2 and No. 3 elimi- 

 nated in this manner .'17 and .'I'.' per cent . respect i vely. Although the 

 rabbits fed inorganic phosph,,nc excreted a larger amount of phos- 

 phorus in the urine than did the others, they retained on the average 

 less of the absorbed phosphoric. 



The ratio of nitrogen ! phosphorii acid in the food is but slightly 

 above :i:l. Thi- -ho\\s a much larger proportion of phosphoric acid 

 than c usually fed in a normal diet. The ratio of nitrogen to phos- 

 phoric acid in the urine TOU16fl from .', : 1 to 7..VI, being higher in the 

 of the rabbits fed organic phosphoric. o\\ ing to the relatively 

 T elimination of phosphoric acid in the urine of those fed inor- 

 ganic phosphoric. The ratio in the fooefi i- rather constant , averaging 

 about 1.1:1 in all eases. The e\ad rat ios are given in Table IT. 



T \ IM I 1 1 . /.' /' - I mi i mini pa 'mtl. 



PRINCIPAL FEEDING PERIOD. 



The principal feeding experiment extended over a period of four 

 \\eeks, and during this time complete nitrogen, phosphoric' acid, cal- 

 cium, and magnesium balances \\ere determined, as well as the ether- 

 alcohol soluble phosphorus balance. In addition the inorganic phos- 

 phorus in the urine was determined by the uranium-acetate titration 

 method. Other salts, as well as the calcium and magnesium salts, 



