48 METABOLISM OF ORGANIC AND INORGANIC PHOSPHORUS. 



was practically the same, varying only from 975 to 1,100 cc per 

 period on an average, and yet the calcium excreted was subject to 

 considerable variation even in the case of the same rabbit fed on the 

 same diet for several weeks. This fact is contrary to the findings of 

 Patterson, who found that on a fixed diet w r ith man the urinary 

 calcium ran parallel to the total amount of urine excreted. Although 

 there was a smaller amount of calcium metabolized by the rabbits fed 

 inorganic phosphorus, yet of this amount a larger proportion was 

 retained than in the case of those fed organic phosphorus. 



By excluding the very abnormally high amount of magnesium 

 found in the urine in the case of rabbit No. 2 (which died), we find 

 a very close agreement in the case of the other three animals, though 

 there is a slight tendency for the rabbit fed organic phosphorus to 

 excrete more magnesium in the urine. The amount of metabolized 

 magnesium that was retained shows that the rabbits fed inorganic 

 phosphorus, while metabolizing a smaller amount of the magnesium 

 than did those fed organic phosphorus, retained a larger per cent of 

 the amount actually metabolized. In man from 29 bo 38 per cent 

 of the ingested magnesium is excreted in the urine, which is higher 

 than in the case of rabbits. The ratio of calcium to magnesium 

 eliminated in the urine is not constant in the cases studied. Accord- 

 ing to Bertram 5 and Renvall, c 29 to 38 per cent of magnesium is 

 excreted in the urine and 62 to 71 per cent is eliminated in the feces. 

 It is more easily excreted through the kidneys than is calcium. The 

 ratio of calcium oxid to magnesium oxid excreted in human urine, 

 according to Klemperer and Tritschler/* varies from 1:0.8 to 1:1.2. 

 The ratio of calcium to magnesium excreted in the feces in the cases 

 of rabbits Nos. 1 and 2 is lower than in the case of Nos. 3 and 4. The 

 ratio of calcium to magnesium excreted by man is held to be 8:1, but 

 in the case of the rabbits the ratio is considerably lower. The amount 

 of magnesium required by man is placed at 0.6 gram per day. In all 

 cases of the rabbits experimented with, daily positive calcium and 

 magnesium balances were obtained. 



CHEMICAL ANALYSIS OF THE BODIES OF THE BABBITS. 



In all cases the analyses were made on composite samples of two 

 rabbits, and represent the average figures. All analyses were calcu- 

 lated to a water-free basis. 



BONES. 



The bones were freed from the adhering muscular and tendon 

 tissue and placed in a large kettle and boiled for several hours with 

 water until all the flesh could be easily removed. They were then 

 dried in a hot-air bath, again scraped, arid finally ground into a fine 

 powder. The bone powder in the case of the two normal rabbits was 



Bio-Chem. J., 1908, 3:39. cSkand. Ar ch. PhysioL, 1904, 16:94 



b Abs. Chem. Centrbl., 1897, 68:957. d Zts. klin. Med., 1902, 44:337. 



