Distribution of Inorganic Phosphate of Blood. 173 



We find that in general a reduction in the inorganic phos- 

 phate of the blood runs parallel to the degree of severity of the 

 rachitic lesions. It will also be seen that the blood phosphate of 

 rats (on these rather specialized diets) may be greatly influenced 

 by the level of phosphate intake. On normal diets the range is 

 from 5.0 to 8.2, averaging 6.2, and on high phosphorus intake a 

 very wide range from 6.0 to 9.8, averaging about 8.5 (mg. P per 

 100 c.c). 



The dividing line between rickets-producing diets is however 

 sharp. Rats on diets containing 86 mg. per cent, phosphorus all 

 develop rickets and the range of blood phosphate from 2.0 to 5.0 

 averages usually around 3.2. When as little as 75 mg. per cent, 

 phosphorus is added to the diet, the rachitic lesions fail to appear 

 and the blood phosphorus averages between 5.5 and 6.0. 



The study of the blood phosphate on rats under light or cod- 

 liver oil therapy brings up several interesting points. 



table 11. 

 Prevention and Cure of Rickets. 

 Inorganic Phosphate as Mgs. P per 100 c.c. Whole Blood. 





No. of 







Blood Phosphate. 



Diet. 



Deter- 



Treatment. 



Rickets. 











minations. 





















Max. 



Min. 



Av. 



84 



18 



Untreated 



Beading 



4.9 



2.0 



3-2 









+ to + + + 









84 



10 



Mercury vapor lamp 



Beading 



5-4 



2.9 



4.1 









+ to + 









84 



8 



Cod-liver oil prepara- 



Calcification 



5-9 



2.4 



395 







tions 



+ to + + + 









As shown in Table II one group of rats on diet 84 (containing 

 86 mg. per cent. P) were treated with the light from the mercury 

 vapor lamp as a preventive measure. In almost every case 

 complete prevention was secured but the blood phosphorus, while 

 distinctly above that of the controls, was nevertheless in the upper 

 range of rachitic blood. This would seem to indicate that the 

 rats can produce non-rachitic bone at a lower level of phosphorus 

 intake, under the influence of light, than is possible without its 

 presence. 



Curative experiments with cod-liver oil preparations on another 

 group of rats on the same diet show active calcification of cartilage 



