248 DISEASES OF BONE. 



converted into })one. During the first or acute stage, the swelling 

 will be painful to the touch ; the horse will be lame and go very 

 " short " ; there will be more or less fever ; and the animal will 

 keejD shifting his feet, if both legs are affected ; or point the toe 

 and bend the fetlock joint, if only one is implicated. 



TREATMENT.— Blister the part, in the first instance, with 

 biniodide of mercury ointment (1 to 4 of lard), which will almost in- 

 variably eftect a speedy cure, and will generally prevent a recur- 

 rence of the ailment. Give a mild dose of physic, and keep the 

 horse on laxative food. If the animal be a young racehorse, he 

 will probably be fit to resume easy work in about ten days. 



In neglected cases, or if the blister does not succeed in produc- 

 ing the desired effect, and the swelling is very extensive and the 

 jDain great, periosteotomy (p. 242) must be performed without loss 

 of time, in order to admit of the escape of the exudation, which, 

 by the pressure it exerts on the inelastic and highly sensitive 

 periosteum, is the cause of the intense pain and fever. Besides, 

 if the exudation be considerable, and it be allowed to remain 

 between the surface of the bone and the periosteum, death of the 

 bone may ensue ; the process being, that this exudation becoming 

 converted into bone will block up the small canals through which 

 the bone receives nourishment by means of small blood-vessels pro- 

 ceeding from the periosteum. Before operating, w^e should care- 

 fully feel for the position of the extensor tendons (Fig. 7, p. 33) 

 which run down the front of the cannon bone, so that these im- 

 portant structures be not injured. 



II pus forms under the periosteum, periosteotomy should be per- 

 formed without loss of time; for the pus will corrode the tissues, 

 and may give rise to blood-poisoning. 



After a severe case of sore shins, an ai>propriate rest should be 

 allowed, and when the horse is put to work a/^:ain, he should be 

 exercised only on soft ground, so that there may be a minimum of 

 the original cause of the disease, namely, concussion. At first the 

 work should be confined to walking, trotting, and slow cantering, 

 and we should bear in mind that time is the great healer of this 

 disease. When the horse is galloped, the distance should be short, 

 and the work, if need be, repeated, with about half an hour's 

 walking exercise allowed between the " spins," so that the bones 

 of the legs may be saved from long-continued jar. The advisa- 

 bility of warm fomentations after a gallop will naturally suggest 

 itself to the trainer. 



An attack of sore shins, in which the exudation has been exces- 

 sive, will give a more or less rounded appearance to the front part 

 of the cannon bone when viewed in profile. 



