410 ANATOMICAL AND PATHOLOGICAL OBSERVATIONS. 



depressions on the ulcerated surface of the cartilage;* but, 

 with the exception of the enlargement of the corpuscules, and 

 the peculiar development of their contents, no change has 

 occurred in it. A layer of nucleated particles always exists 

 between the loops of capillaries and the ulcerated surface. 



The cartilage, where it is not covered by the false mem- 

 brane, is unclianged in structure. The membrane generally 

 adheres with some firmness to the ulcerating surface ; in other 

 instances it is loosely applied to it ; but in all, the latter is 

 accurately moulded to the former. 



In scrofulous disease of the cancellated texture of the 

 heads of bones, or in cases where the joint only is affected, 

 but to the extent of total destruction of the cartilage over part 

 or the whole of its extent, the latter is, during the progress of 

 the ulceration, attacked from its attached surface. Nipple- 

 shaped processes of vascular cellular textui'e pass from the 

 bone into the attached surface of the cartilage, the latter 

 undergoing the change already described. The processes from 

 the two surfaces may thus meet half-way in the substance of 

 the cartilage, or they may pass from the attached, and project 

 through a sound portion of the surface of the cartilage, like 

 little vascular nipples or granulations. The cartilage may 

 thus be riddled, or it may be broken up into scales of varying 

 size and thickness, or it may be undermined for a greater or 

 less extent, or be throw^n into the fluid of the cavity of the 

 joint in small detached portions, or it may entirely disappear. 



On the principles already laid down, if absorbents exist, as 

 we have reason to believe they do in the false membrane, 

 neither they nor the veins are to be considered as the active 

 or immediate agents in the absorption of the cartilage. They 

 certainly are not so in the absorption of the walls of the cor- 



* The vascular loops described and figured by Mr. Listen are not vessels 

 in tlie cartilage, but the vessels described in the text. — Liston. Lond. Med. 

 Chir. Trans. 



