CHEMICAL COMPOSITION OF BONE. 369 



weight, and to have become exceedingly brittle ; 

 this, as already mentioned, being the natnral pro- 

 perty of phosphate of lime, when deprived of its 

 animal cement. We may perceive on the surface 

 of a bone so treated, a number of minute cre- 

 vices, showing where this animal substance had 

 been situated in its original state. On breaking 

 the bone across, we may also discover the size 

 and shape of the cavities which contained the 

 marrow, or oily fluid above-mentioned. 



It is easy to reverse this process by steeping 

 the bone in an acid sufficiently diluted to pre- 

 vent its injuring the animal membrane, but yet 

 sufficiently powerful to dissolve the phosphate 

 and carbonate of lime. Diluted nitric or mu- 

 riatic acids may be used for this purpose, and 

 will, in this way, gradually separate the earthy 

 particles from the membranous portion of the 

 bone. During the action of the acid a few 

 bubbles of carbonic acid gas make their ap- 

 pearance, indicating the presence of a small 

 quantity of carbonate of lime, which always 

 exists in bones, intermixed with the phosphate. 

 The phosphate may be recovered from its solu- 

 tion in the acid by precipitation with a pure 

 alkali, such as a solution of ammonia. This 

 precipitate is readily dissolved, without effer- 

 vescence, by nitric, muriatic, or acetic acids. 

 A small quantity of sulphuric acid may also be 

 detected in the fluid by the addition of nitrate 



VOL. I. p. li 



