bones: diseases and accidents. 273 



goes a change and is gradually converted into bone, forming a ferrule 

 on the outside and a plug on the inside, which serve to hold the part 

 in position. In the fonrth stage, extending to about the sixth month, 

 the whole of the new structure is converted into bone. The fifth 

 stage, extending up to the end of the first year, the callus is absorbed, 

 being no longer necessary, and the connection between the cavities 

 of the two bones is again established. 



Common complications. — The process of union just described is 

 healthy and normal. Diseased conditions may at any time supervene 

 during the treatment and render the operation unsuccessful. In the 

 case of compound fracture, the open wound communicating with the 

 ends of the bones, a septic condition is apt to arise which may become 

 so serious as to endanger the animal's life and bring about conditions 

 which in human surgery would indicate amputation. Although that 

 operation is not a general one in veterinary practice, there is no rea- 

 son why it should not be attempted as a last resort, particularly if the 

 animal be valuable or one whose existence is necessary in order to 

 perpetuate some valuable strain. Even in the simplest form of frac- 

 ture, if the splints or bandages are improperly applied and the frac- 

 tured bone left so loosely guarded that the broken ends move one upon 

 another, the formation of the calluses previously described is likely 

 to be interfered with, and in place of a strong, rigid, and healthy 

 union a formation of elastic cartilage is the result. This false struc- 

 ture unites the broken ends of the bones in such a way that they move 

 one upon another, depriving the bone of its stability and usefulness. 

 When once the healthy process of union is interrupted in the manner 

 just described, it is with great difficulty that it can be again estab- 

 lished. It no longer does any good to continue the restraining power; 

 in fact, the change of the temporary cartilage into bone is more likely 

 to be reestablished if the parts move violently upon one another for a 

 short time so as to set up and renew the process of inflammation. 

 Then if the restraint be again applied there is some chance of union. 

 In order so far as possible to avoid this danger, care should be exer- 

 cised that the bandage fits closely and that it is kept on till there is 

 no longer any danger but that a perfect union has taken place. It is 

 impossible to say at just what time the splints or bandages can safely 

 be removed. In a young and healthy animal of quiet temperament, 

 where the parts have been firmly held in position throughout the 

 whole time, from thirty to forty days may be regarded as reasonably 

 safe. Under more unfavorable conditions as to age, vitality, and 

 restraint, the period would better be extended up to sixty days if the 

 general condition of the animal is such as to permit of so long a con- 

 tinuance. After the appliance has been removed the animal should 

 be allowed to stand quiet for a few days, then given very gentle exer- 

 cise, gradually increased over a period of a week or ten days, by 



61386—08 18 



