BONE-SPAVIN. 269 



and is compressed between the skin and the enlarg-ed bag' ; and, conse- 

 quently, the passage of the blood throu<^h it is partially stopped. The 

 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 inside 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 me- 

 dical 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 to more 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 diffi' 

 culty operated upon. Uniform pressure will sometimes cause the absorp- 

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

 such extensive motion as the hock, it is difhcult, 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 pass- 

 ing- 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 temporary 

 success, is by exciting a great deal of inflammation on the skin, and thus 

 rousing the deeper seated absorbents to carry away the fluid efRised in the 

 enlarged bag. Repeated blisters then will afford the fairest prospect of 

 removing the tumour, or firing may be tried ; but in the 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 tVot 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 

 attempt to make him. 



BONE-SPAVIN. 



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

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

 of the leg, the shank-bone .§•, page 266, and the two little splint-bones 

 behind, h, 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 sphnt-bone. The middle wedge bone,/, 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 litde 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, should suffer material injury. The smith increases the tendency to 



