18 OSSEOUS TISSUE. 



nor von Bibra could recognize any difference between the ele- 

 mentary composition of this cartilage and of the glutin obtained 

 from it or from tendons or connective tissue. The analyses of 

 thoroughly pure bone-cartilage and of glutin coincide so accurately 

 with one another, that notwithstanding their somewhat high 

 atomic weights, we must regard these substances, if not isomeric, 

 at all events as polymeric, although we always find a little sulphur 

 in the former, which is absent in the latter. Bibra* has made the 

 interesting observation, that in fossil bones in which the organic 

 substance is still retained, the cartilage is converted into a glutin- 

 like substance or into true glutin. After freeing these bones in the 

 ordinary manner from their earthy constituents, it was found that 

 the residual cartilage fused at a temperature at from 37 to 40 into 

 a thoroughly gelatinous mass, which swelled up in water into a 

 trembling jelly. This only took place, according to Bibra, in true 

 fossil bones, and not in those which were obtained from ancient 

 graves. We shall postpone the description of the characters of 

 the cartilage which occurs in bones before true ossification takes 

 place, till we treat of cartilage generally. Neither Bibraf, 

 Ragsky, J or any other chemists have found any essential alteration in 

 the cartilage of diseased bones; in all cases the cartilage was converted 

 by boiling with water into a substance perfectly similar to glutin. 



As we have already described in considerable detail (in the 

 first volume) the individual mineral constituents of bones, and the 

 varying quantities in which they occur, we shall here merely pre- 

 sent the reader with a general scheme representing the constitution 

 of compact osseous tissue, as deduced from the best analyses : 



Phosphate of lime . . 57 



Carbonate of lime ... 8 



Fluoride of calcium ... 1 



Phosphate of magnesia . , 1 



Mineral constituents ... 67 



Cartilage ..... 33 



100 



The fluctuations, in the proportions of the individual constitu- 

 ents are by no means inconsiderable under different physiological 



* Chem. Untersuch. liber die Knochen u. Zahne. 1844,8. 399. 

 t Op. cit. p. 319. 



$ Rokitansky's Handb. d. pathol. Anat. Bd. 2, S. 205 [or English Tiansl. 

 Vol. 3, p. 182].j 



