262 Existence of Phosphate of Magnesia in Bones. 



tweeii the body of a cylindrical bone and its epiphysis. They 

 each remain onlv for a certain length of time ; each allows 

 the interposition of a secretory orsan ; and both begin to be 

 obliterated, when the bones with which they are connected 

 have completed their growth^ and their continuance is no 

 longer necessary. 



L. On the Existence of Phosphate of Magnesia in Bones. 

 By M. FouRCROY *. 



Jl he discovery of a new earthy phosphate in the bones of 

 animals, is a fact in the history of the physical sciences im- 

 portant enough to deserve a place in every journal calculat- 

 ed to promote improvements in natural history. This dis- 

 covery has been made these two years by M. Vauquelin, 

 and myself, in the course of a very extensive inquiry under- 

 taken upon animal concretions, and of which we have from 

 time to lime given an account to the public. 



Having discovered, 1st, the ammoniacal magnesian phos- 

 phate among the materials of the calculi in the human 

 bladder, and aniong the intestine bezoars of animals ; and 

 Sdly, the phosphate of magnesia in human urine, and the 

 property which characterizes it, in this liquid, of passing to 

 the state of a triple salt very crystaliizable, at the moment 

 that the urine becomes ammoniacal by its spontaneous de- 

 composition} it appeared to us important to inquire if this 

 magnesian salt, unknown in animal matters until our in- 

 quiries, was not to be found in some ar)imal organs ; and we 

 began our inquiries upon bones, the analogy of which with 

 the urinary receptacles is so well known by physiologists. 

 The analysis of these organs seemed to be brought to perfec- 

 tion ; and yet the new experinients to which we submitted 

 the substance under examination, enabled us to discover this 

 salt by methods and processes much more complicated than 

 those which have been hitherto employed in this species of 

 analysis. 



♦ from Annates du Museum d'Histoire Naturdle, vol. vi. 



In 



