30 OSSEOUS TISSUE. 



when compared with the cartilage in this form of osteomalacia, as 

 will be readily seen if we exclude the fat in the calculation of the 

 analysis. It is remarkable that notwithstanding the acid reaction 

 of the juice permeating the bone, carbonate, as well as phosphate 

 of lime, is found in the macerated bones from which the fat has 

 been removed, and that the former even appears to be less 

 decreased than the latter. Weber is the only one who has inves- 

 tigated the composition of the phosphate of lime contained in these 

 bones ; he found, in addition to carbonate of lime, f basic 

 phosphate of lime, and believes that the phosphate of normal bone 

 (3 Ca O. PO 5 ) is converted by means of the free acid into this less 

 basic salt. If this interesting fact should be confirmed by future 

 investigations, it must still appear very striking that so much car- 

 bonate of lime could be present in fresh bone, together with the 

 free acid. The affections which we comprehend under the term 

 osteomalacia may, therefore, possibly admit of being subdivided 

 into two different processes. It will in like manner depend upon 

 future and more carefully conducted investigations to determine 

 whether, as we are induced from various reasons to believe, the 

 arthritic process actually corresponds with that of osteomalacia. 



Carious bones, the products of ulcerous ostitis, have been very 

 carefully examined by Valentin* and von Bibra.f The ulceration 

 so gradually destroys the bone, that the mineral constituents dis- 

 appear to a greater extent even than the cartilage before the entire 

 destruction of the osseous tissue, and that the cavities formed in the 

 bones by caries become filled with fat in the same manner as in 

 osteomalacia ; hence we always find a larger quantity of organic 

 matter in carious than in normal bones : the residual cartilage does 

 not differ from the ordinary bone-cartilage, or at all events the 

 decoction exhibits the usual reactions of glutin. It appears from 

 most analyses that the carbonate of lime diminishes in direct pro- 

 portion with the phosphate. Bibra endeavoured to ascertain 

 whether the phosphate of lime exhibited any difference in the pro- 

 portions of its proximate constituents in caries ; he found f basic 

 phosphate of lime, but further investigation was required to deter- 

 mine this question decisively. 



The chemical investigation of portions of necrosed bone has 

 not yet led to any important results ; nor can we wonder at this, 

 when we consider the conditions under which separate bones, or 

 portions of bones, are necrosed : that is to say, how they are 



* Valentin's Repert. 1838. 



t Pogg. Ann. Bd. 57, S. 356-372. 



