60 METABOLISM OF ORGANIC AND INORGANIC PHOSPHORUS. 



degeneration of the livers of rabbits Xos. 1 and 2. The liver of rabbit 

 No. 4 also shows fatty degeneration, but less marked, while rabbits 

 Nos. 5 and 6 show normal livers. That the harmful effects noted 

 are due to the excessive amounts of phosphorus fed either organic 

 or inorganic, is proven from the cases of the normal rabbits which, 

 although likewise kept in cages, showed apparently normal livers. 

 In reviewing the phosphorus literature it was noticed that in several 

 cases rabbits fed on organic phosphorus were reported to have died 

 of pneumonia, as did rabbit No. 2 in the experiments here recorded. 



Six photomicrographs are appended, which show sections of the 

 livers of rabbits Xos. 1, 2, and 4. The tissue in the case of rabbit 

 No. 3 was exhausted before an osmic acid slide was prepared and it 

 was therefore impossible to give a reproduction in this case. The 

 photomicrographs in which the fat is shown stained black in position 

 demonstrate that degeneration as well as fatty infiltration has taken 

 place in the livers of both of the organic and in one of the inorganic- 

 phosphorus-fed rabbits. 



The author is indebted to Doctor Mohler, of the Bureau of Animal 

 Industry, for his interpretation of the microscopic slides, in regard to 

 which he makes the following statement: 



The section in the case of rabbit No. 1 (PI. I) shows a more marked and advanced 

 lesion of fatty degeneration than do the three remaining cases. In this case fatty 

 infiltration is also present and occurs principally on the periphery of the lobules and 

 in the tract supplied by branches of the portal vein, while the fatty degeneration is 

 more abundant in the central zone around the hepatic vein. In fatty degeneration 

 the fat is usually in minute granules, which may coalesce to form small droplets, 

 but only in the most advanced stages do they form large drops as is the case in fatty 

 infiltration. 



The sections in which the tissue has been treated with Fleming's solution show the 

 lesion best, as the contrast of the black-stained fat is so marked as compared with the 

 light hepatic parenchyma that photomicrographs may be readily made.- The Soudan 

 III sections, while valuable for demonstration purposes, can not be reproduced as well 

 on account of less contrast and the red color. 



The section in the case of rabbit No. 4 (PI. Ill) shows a less advanced stage of fatty 

 degeneration; there is also not much fatty infiltration present. In the section in the 

 case of No. 2 (PI. II) there is still less fatty degeneration present, while the section of 

 rabbit No. 3 does not show any degeneration and only a little fatty infiltration. 



CONCLUSIONS. 



The somewhat limited experimental data here reported point to the 

 following conclusions, which may be altered by more extensive work 

 on the subject. 



PRELIMINARY FEEDING PERIOD. 



During the preliminary feeding period, the rabbits fed on organic 

 phosphorus excreted a slightly larger proportion of nitrogen in the 

 urine than did the rabbits fed on inorganic phosphates, but retained 



Made by B. J. Howard, Chief, Microchemical Laboratory, Bureau of Chemistry. 



