2(54 Existence of Phosphate of Magnesia in Borip^. 



rates the lime of the phosphoric acid ; but it only separate^ 

 a very small quantity from it, and only when potash is em- 

 ployed by itself in a great quantity, while lime takes the pot- 

 ash from the phosphoric acid entirely and completely. We 

 have here the effect of the power of masses, called in by 

 Berthollet in order to explain some apparent anomalies in 

 the action of the elective attractions. 



Ox bones calcined contain about a 40th part of phosphate 

 of magnesia. 



Those of horses and sheep yielded a 36th part. 



Those of the feathered creation, about a 40th pari. 



We were not able to extract, from any of the above, a 

 quantity any thing equal to that contained in human bones. 



We have to remark on this occasion, that ox bones, which 

 ■we had most frequently and most exactly analysed, appeared 

 to contain the following materials : 



Solid gelatine 51-0 



Phosphate of lime ^ 37' 7 



Carbonate of lime lO'O 



Phosphate of magnesia 1*3 



The phosphate of magnesia existing in animals manifestly 

 arises from their food. Not only have we found this salt 

 in wheat, barley, oats, and vetches, but we discovered it in 

 all the grasses named by Linnaeus ccrealia, in the proportion 

 of a centieme and a half of their weight ; which is almost 

 double the quantity of the phosphate of lime which they 

 contain. Without douBt, some relation subsists bctvicen this 

 fact and those concretions found in the intestines of anir 

 mals, which are formed of ammoniacal magnesian phos- 

 phate. 



It is not impossible to conceive why human bones do not 

 contain phosphate of magnesia, although this salt exists 

 more abundantly than the phosphate of lime in flour, &c. 

 It appears that it is evacuated by those urines in which we 

 have discovered it, while it does not exist in the urine 

 of such animals as throw it off by the skin or the intestines. 



Without pushing too far the influence of chemical dis- 

 coveries upon the animal oeconomy, made by the analysis of 



3 various 



