BONE-SPAVIN. 209 



and is compressed between the skin and the enlarged bag; and, conse- 

 quently, the passage of the blood through it is partially stopped. Th* 

 blood, however, continues to be returned from the leg and foot, and being 

 thus arrested in its course, a portion of the vein below the impediment, and 

 between it and the next valve, is distended, and causes the soft tumour 

 on the side of the hock, called the bog or blood spavin. This is a very 

 serious disease, attended with no great, but often permanent lameness, and 

 a disease too apt to return, when the enlargement has subsided under med- 

 ical treatment. It must be considered as decided unsoundness. In a 

 horse for slow draught, it is scarcely worth while even to attack it. In a 

 horse destined for rapid action, the probability of a relapse should not be 

 forgotten, when the chances of success, and the expenses of treatment are 

 calculated. 



The disease (the enlarged mucous capsule) lies deep, and is with difficulty 

 operated upon. Uniform pressure will sometimes cause the absorption of 

 the fluid contained in cysts or bags like these, but in a joint of such 

 extensive motion as the hock, it is difficult, or almost impossible, to confine 

 the pressure on the precise spot where it is required ; and could it be made 

 to bear on the enlarged bag, it would likewise press on the vein, and to a 

 greater degree hinder the passage of the blood, and increase the dilatation 

 below the obstruction. The old and absurd method of passing a ligature 

 above and below the enlarged portion of the vein, and then dissecting out 

 .the tumour, is not, in the advanced stage of veterinary science, practised by 

 any surgeon who has a regard to his reputation. The only method of 

 relief which holds out any promise even of temporaiy success, is by ex- 

 citing a great deal of inflammation on the skin, and thus rousing the deeper 

 seated absorbents to carry away the fluid eff'used in the enlarged bag. 

 Repeated blisters then will aflxDrd the fairest prospect of removing the tumour, 

 or firing may be tried ; but in tlie majority of cases, the disease will bid 

 defiance to all our means, or will return, and baffle our hopes when we had 

 seemed to have been accomplishing our object. A horse with bog-spavin 

 will do very well for ordinary work. He may draw in a cart, or trot fairly 

 in a lighter carriage, with little detriment to his utility, but he will never 

 do for rapid or hard work, and it is in vain to attemot to make him. 



BONE-SPAVIN. 



A still more formidable disease ranks under the name of spavin, and is 

 an affection of the bones of the hock-joint. We have observed that the 

 bones of the leg, the shank-bone, g, page 266, and the two little splint-bones 

 behind, k, support the lower layer of the bones of the hock. The cube 

 bone, d, rests principally on the shank-bone, and in a slight degree on the 

 outer splint-bone. The middle wedge-bone, f, rests entirely upon the 

 shank-bone, and the smaller wedge (not seen in the cut) rests in a very 

 slight degree on the shank-bone, but principally or almost entirely on the 

 inner splint-bone. Then the splint-bones sustain a very unequal degree of 

 concussion and weight. Not only is the inner one placed more under the 

 body, and nearer the centre of gravity, but it has almost the whole of the 

 weight and concussion communicated to the little wedge-bone carried on to 

 it. It is not, therefore, to be wondered at, that in the violent action of this 

 joint in galloping, leaping, heavy draught,, and especially in young horses, 

 and before the limbs have become properly knit, the inner splint-bone, or 

 its ligaments, or the substance which connects it with the shank-bone, 

 shouii suffer material injury. The smith increases the tendency to this, 



