BONES DISEASES AND ACCIDENTS. 289 



tietii day, according to age and strength of the animal, the fibre-car- 

 tilaginous structure undergoes a change and is gradually converted 

 into bone, forming a ferule on the outside and a plug on the inside, 

 which serve to hold the part in position. In the fourth stage, extend- 

 ing to about the sixth month, the whole of the new structure is con- 

 verted into bone. The fifth stage, extending up to the end of the first 

 yrur, the callus is absorbed, being no longer necessary, and the connec- 

 tion 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 seri- 

 ous as to endanger the animal's life and bring about conditions which 

 in human surgery would indicate amputation. Although that opera- 

 tion is not a general one in veterinary practice, there is no reason 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 fracture, if the 

 splints or bandages are improperly applied and the fractured 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 structure 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^jnterrupted in the manner just described, it 

 is with great difficulty that it can be again established. 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 as far as 

 jMjssible to avoid this danger, care should be exercised that the band 

 age 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 unfavor- 

 able conditions as to ago, vitality, and restraint, the period had bettor 

 be extended up to sixty clays if the general condition of the animal is 

 such as to permit of so long a continuance. After the appliance has 

 been removed the animal should be allowed to stand quiet for a few 

 days, then given very gentle exorcise, gradually increased over a period 

 of a week or ten days, by which time the patient will be so far recovered 

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