86 



Nor the morbid 

 concretions 

 called urinary 

 calculi. 



Tlie bones alfo 



differ. 



Thofe of animals 



contain phof- 



phate of mag- 



nelia } .thofe of 



man do. nop. 



Method of fe» 

 parating mag- 

 nefia from the 

 bones of ani- 

 mals. 



KEW EARTHY PHOSPHATE. 



cwinjy. We endeavoured to prove In thofe effjys that none of 

 (he falls called phofpliates, (which exift in abundance' in the 

 urine of man) are to be found in the urme of mamiferous ani- 

 nmls, that Iheir kidnejs are not the cbncretory of thefe faline 

 combinations; but that the hair which covers their fkin, and 

 the corneous appendages which defend their extremities, are 

 the organs and repofitories in which nature fecretesand depofits 

 thefe falls in thebody'of animals. 



We have alfo {]iown that the morbid and preternatural con- 

 cretions, called urinary calculi of man, contain befides uric 

 acid, alfo phofphate of lime and phofphate of magnefia; none 

 of which are met with in thofe of animals j and that on the 

 contrary, the ftony concretions found in the inteftinal canal of 

 animals, always contain phofphates of different kinds, whereas 

 the concretions met with in the inteftines of man, do not con- 

 tain a veftige of them. 



We tliall now endeavour to prove that the bones of ani- 

 mals alfo differ in compofition from thofe of men. We have 

 found that the former contain, befides phofphate and carbonate 

 of lime, alfo phofphate of magnefia; tlie latter of which has 

 hitherto efcaped the notice of chemifis. This fait which we 

 have detefted in the bones of all the animals we hitherto ex- 

 amined, does not at all exifi in the bones of man. We fiiall 

 firfl: ftate the method we employed for detedingand feparating 

 it, and then point out the relative proportions in which it ex- 

 jfts in different animals, ^ 



Take a quantity of bones of adult animals, burn them to 

 vvhitenefs in an' open fire, and reduce them to a fine powder. 

 Upon one part of this powder, after having been put into a- 

 convenient earthen or glafs vefleJ, afFufe an equal quantity by- 

 weight of concentrated fulphuricacid; ftir the mixture inti- 

 mately together, and then fuffer it to ftand for five or fix days. 

 Having done this, dilute the mafs with at leaft ten times its 

 bulk of water, agitate it well and" transfer it on a flrainer. 

 When no more fluid palles, difFufe the mafs again through five 

 times its quantity of water, and ftrain agaiji as before, and re- 

 peat this procefs till the water runs tafielefs. The fluids thus 

 obtained, are to be added together, iand mingled with liquid 

 ammonia, taking care ihe latter be in excefs. The preci- 

 pitate which is obtained conlifis of phofphate of lime, phof- 

 phate of ammonia, and phofphate of magnefia. To feparate 

 , ■ ■ ' . ■• ' thefe 



