NECROSIS OF TISSUES. 15 



the fact that the tint in question is constantly exhibited by the 

 cartilages of the larynx and trachea, when these are isolated by 

 suppurative perichondritis. The microscope displays a granu- 

 lar opacity of the inter-cellular substance, which melts away at 

 its edges into a gelatinous mass. The cartilage cavities are 

 o;enerallv full of oil globules, due to fatty degeneration of the 

 contained cells ; these oil globules are set free when the tissue is 

 finally dissolved. 



§ 21. Bone tissue remains unaltered during necrosis. The 

 surgeon who, amid the most striking variety of inflammatory and 

 ulcerative changes in a bone, recognises a portion of it as the 

 dead part, the sequestrum, by its smooth surface and unaltered 

 form, has every reason to rely on the truth of the above state- 

 ment. Meanwhile, it is right that we should clearly understand 

 how far we may apply this doctrine of the " unaltered state" of 

 bone tissue in its literal sense. Of course we must always be 

 prepared to meet with those changes in the fragment of necrosed 

 bone which are common to all the bones of the skeleton during 

 somatic putrefaction. Cells, vessels, and medullary tissue all 

 disappear. It would seem, farther, that a great part of the 

 organic matrix, the bone cartilage (ossein), is destroyed by 

 putrefaction, the amount destroyed being proportionate to the 

 length of time during which it has been exposed to the disor- 

 ganising influence. But for this it would not be possible to 

 account for the notable fact that the specific gravity of sequestra 

 is always far below that of normal bone. Cases occur, more- 

 over, in which the sequestrum, owing to a gradual corrosion of 

 its surfiice, loses not only its original polish, but also a part of 

 its bulk. Indeed, it is hard to see why complete solution of the 

 necrosed bone tissue should not take place under suitable con- 

 ditions. The presence of even a minute proportion of some acid 

 in the fluids of tlie part would suffice to bring this about ; and 

 the earthy salts once dissolved, the residual ossein would not offer 

 any greater resistance to putrefaction than articular cartilage and 

 other allied structures. In the meantime, we must rest content 

 with the facts as they stand. As regards the mode in which the 

 disintegration of bone takes place (which, be it said in passing, 

 is nearly the same in dead as in living bones), this will be 

 dealt with elsewhere. (See softening of bone, rarefactive ostitis, 

 caries, &c.) 



