168 DISEASES OF THE BONES AND ARTICULATIONS. 



Treatment. — ^When caries is firmly established, the only 

 method by which it can be repaired is by assisting the process 

 of adhesion between the opposing surfaces. This is to be effected 

 by rest ; and by the actual cautery, which has a wonderful 

 effect in allaying the diseased action and removing the pain. It 

 also promotes the formation of reparative material, and hastens 

 the process of repair. It must be understood that when anchy- 

 losis occurs in articulations with extensive motion, such as the 

 true hock, elbow, &c., the animal is of little use, and no treat- 

 ment is of any avail ; but when caries is commencing in these 

 situations, its progress may be arrested by rest and the cautery, 

 or other severe external irritant. But when the mere gliding 

 joints are its seat, then anchylosis may be looked upon as a 

 radical cure. 



Necrosis, or death of a bone, corresponds to mortification of 

 the soft structures, and is as distinct from caries as mortification 

 is from ulceration. Necrosis is divided into four varieties, 

 namely, \st, the scrofulous ; 2cl, the superficial, or that which in- 

 volves the outer lamella, and presents itself in the flat and long 

 bones ; 2>d, that form which destroys the internal part of a bone, 

 and in which the outer shell is not affected ; and 4dh, that in 

 which the whole thickness of the bone dies. The last three 

 forms are respectively named external, superficialis or partialis, 

 central or internal, and general necrosis, or necrosis totalis. 



Necrosis superficialis depends upon very acute superficial 

 ostitis, periostitis, or any injury which destroys the periosteum, 

 as well as injuring the bone itself. It was thought at one time 

 that the mere removal of the periosteum was sufficient to pro- 

 duce this form of necrosis, but it is now ascertained that such is 

 not the case, and that when necrosis and exfoliation occur, they 

 do so from the violence which separated the periosteum having 

 destroyed the vitality of the bone itself. 



I am not aware that this form occurs except from direct 

 violence to the part, such as blows, kicks, &c., which expose the 

 surface of the bone, and excite inflammation in the adjoining 

 tissues. The necrosed portion presents a white, waxy appear- 

 ance, as if it had been carefully macerated, sonorous when struck 

 by a probe, and if exposed to the atmosphere before separation, 

 it becomes changed in colour, passing through various degrees of 

 green, brown, and black. These changes are attributed to the 



