Phosphoric Acid in Blood in Rickets 



373 



to show that there are three types of acid soluble phosphorus 

 in mammalian blood, namely : inorganic, an organic phosphoric 

 acid compound readily hydrolyzed in neutral or slightly acid 

 solutions, and lastly the "nonhydrolysable phosphate," which 

 cannot be broken down by boiling four hours in dilute acids, 

 but can be determined as inorganic phosphate only after diges- 

 tion with concentrated nitric and sulfuric acid. In order to 

 complete the blood picture of rickets, we have done complete 

 analyses of the acid soluble phosphorus according to the above 

 scheme on rachitic and non-rachitic children. The results are 

 shown in Tables I and II below. 



Here we see that the total acid soluble phosphorus is not lower 

 in rachitic than in normal children, except where the rickets is 

 complicated by anemia. In these cases we would naturally ex- 

 pect a low total acid soluble phosphate since it has been known 

 for some time that by far the greater part of the phosphorus 

 of the blood occurs in the red cells. In anemia, however, the 

 inorganic phosphate is not low. 



In rachitic children the inorganic phosphate is not only lower 

 in actual amount than the normal, (2.7 mg. against 4.6 mg.) but 

 its percentage of the total is also lower. (13 per cent, against 

 22 per cent.). 



The non-hydrolysable is increased above the normal (57.8 per 

 cent, against the normal 48.5 per cent.). 



Similar analyses were done on rachitic and non-rachitic rats 

 (Table III). Here again we find in the rachitic animals a 

 lowered inorganic phosphate (2.9 mg. or 15 per cent, as opposed 

 to 6.2 mg. or 27 per cent, of the total acid soluble), and the 

 increase of the non-hydrolysable. 60.7 per cent, against 42 per 

 cent, in the normal). Owing to the fact that the blood phos- 

 phorus in rats can easily be influenced by the phosphorus level of 

 the diet (not the case in human beings) the total acid soluble 

 phosphate does not show the same constancy. 



The significant facts shown by our data are : 



1. In rickets the total acid soluble phosphate does not fall 

 below the normal range. 



2. The inorganic phosphate is reduced in rickets by an in- 

 crease of the non-hydrolysable, the organic hydrolysable remain- 

 ing the same. 



3. In anemic blood the total acid soluble phosphate may be 

 low without affecting the inorganic phosphate. 



