176 VBTEEIKAKY MEDICINE AND SURGERY. 



sprain, the wearing of shoes witli too high heel calks, which gives rise 

 to inflammation in either the cuneiform bones of the hock, or the tissues 

 in their immediate neigliborhood. 



As a general rule, exostoses on the exterior of the bones arise from 

 sprains of the ligaments of the hock, whilst the more common ones 

 between the bones are produced by pressure and concussion. 



Percivall says: *•' I am very much disposed to believe in the exist- 

 ence in the system of what I would call an ossific diathesis. I have most 

 assuredly seen unbroke colts so prone in their economy to the production 

 of bone, that, without any assignable outward cause — without recogniza- 

 ble injury of any kind — they have at a very early age exhibited ring- 



FiG. 84. 

 Bone Spavin. 



bones, and splints, and spavins. There might have been something 

 peculiar in the construction of their limbs to account for this; at the 

 same time there appeared a more than ordinary propensity in their 

 vascular system to osseous effusion. Growing young horses — and par- 

 ticularly such as are what is called ' overgrown ' — may be said to be 

 predisposed to spavin, simply from the circumstance of the weakness 

 manifest in their hocks, as well as other joints. When horses whose 

 frames have outgrown their strength, with their long and tender limbs, 

 come to be broke — to have weight placed upon their backs at a time 

 when the weight of their own bodies is as much as they are able to bear 

 — then it is that the joints in an especial degree are likely to suffer, and 

 wind-gall and spavin to be the result. Indeed, under such circum- 

 stances, spavin, like splint and other transformations of soft and elastic 

 tissue into bone, may be regarded as nature's means of fortification 

 against more serious failures." 



