40 INTRODUCTION. 



the phosphate of soda. That this decomposition takes place 

 in the body, is evident from the fact that the ingestion. of a 

 considerable quantity of common salt has been found, in the 

 sheep, to increase the quantity of chloride of potassium in 

 the urine, without having any influence on the amount of 

 chloride of sodium. The chloride of potassium is discharged 

 from the body in the urine and mucus. 



Phosphate of Lime, 3 CaO, PO B . 



Phosphate of Lime is found in all tire solids and fluids of 

 the body. As it is always united, in the solids, with organic 

 substances as an important element of constitution, it is 

 hardly second in importance to water. It differs in its func- 

 tions so essentially from the chlorides of sodium, and potas- 

 sium, that they are hardly to be compared. It is insoluble 

 in water, but held in solution in the fluids of the body by 

 virtue of free carbonic acid, the bicarbonates, and the chlo- 

 ride of sodium. In the solids and semi-solids, the condition 

 of its existence is the same as that of water ; i. e. it is incor- 

 porated, particle to particle, with the organic substance char- 

 acteristic of the tissue, and is one of its essential elements 

 of composition. Nothing need be added here as to this mode 

 of union in the body of organic and inorganic substances, 

 after what has been said under the head of water. 



The following table 1 gives the relative quantity of phos- 

 phate of lime in various situations : 



Table of Quantity of Phosphate of Lime. 



Parts per 1,000. 



In Arterial Blood, ) Poggiale and Marc hal i ' 790 



Venous Blood, J \ 0-760 



" Milk, Human (Pfaff and Schwartz) 2-500 



" Saliva (Wright) O'GOO 



Selections from the table of Robin and Verdeil, op. tit. 



