INOKGANIC CELL-CONSTITUENTS. 131 



constituents of all animal fluids and tissues. In the ash of the blood of 

 the herbivorous animals a smaller amount of the alkaline phosphates is 

 found than in the carnivora. Grain-eating animals show a larger amount 

 of phosphatic salts in the ash of their blood. Ornnivora occupy a mean 

 between the two. On account of their great solubility in the organism 

 the phosphates must nearly always exist in the form of a solution, espe- 

 cially in the acid fluids, as in urine, muscle-juice, and the parenchymatous 

 fluids of certain glands. In muscles, together with lactic acid, thev 

 occasion the acid reaction of the muscle-juice. 



Phosphates are taken into the animal body with food, though they 

 may also doubtless originate in the blood through a double decom- 

 position of potassium phosphate and sodium chloride into sodium phos- 

 phate and potassium chloride. The alkaline phosphates leave the body 

 through the kidneys and intestines. The former is the case especially in 

 the urine of the carnivora, where it forms twelve-thirteenths of the 

 total amount of these substances eliminated. In the urine of the 

 herbivora but small amounts of phosphates are found, in spite of the 

 fact that in their food phosphates of the alkalies and earthy phosphates 

 are invariably present. This is to be explained b} T the supposition that 

 the salts of the organic acids, with the alkaline earths, undergo decompo- 

 sition into earthy phosphates and carbonates of the alkalies, the latter 

 being eliminated through the urine. From their great abundance and 

 wide distribution in the animal economy, it follows that they must be of 

 great importance. 



The phosphate of potassium is especially abundant in the blood- 

 cells, ovum, and in muscular tissue. In the latter case, combined with 

 lactic acid, it is the main cause of their acid reaction, while phosphate 

 of sodium is found in blood-plasma. These salts enter the organism as 

 constituents of food, either in the form in which they are found or as 

 the result of decomposition of the earthy phosphates and other alkaline 

 salts. This is especially probable on account of the great abundance of 

 potassium phosphates and potassium chloride in the fluids of muscle and 

 other tissues, while sodium chloride and sodium phosphate, being found 

 in abundance in the blood, it is evident, from the proportion in which 

 these different substances are found in the different tissues, that they 

 have not been derived directly from the blood. Again, it is to be 

 remembered that the herbivorous animals in their food receive almost 

 solely potassium salts, and, since sodium phosphate is necessary for the 

 integrity of their blood, it is clear that this must be formed in the body 

 through the decomposition of potassium phosphate and sodium chloride. 

 In the blood the alkaline phosphates give to the plasma its alkaline 

 reaction, to which its great capacity for dissolving carbon dioxide is 

 apparently due, since it has been found that water, which holds only 



