PECULIAK TO HORSES. 95 



Local preduposition is determined by a short-pointed hock, 

 lengthy cannon^ and iipriglit pasterns. This is the kind of liock 

 that is most subject to strain, in backing heavy loads, and concussion^ 

 while galloping, or trotting fast on hard pavements. 



Constitutional predisx>osition exists in breed, and is inherited 

 from sire or dam. A spavined mare transmits the disease, of which 

 we have evidence in colts that have never been brol^ie. But in the 

 majority of cases, spavins are indirectly transmitted in the form of 

 a weak, fragile, bony structure, which i'^ prone to throw out osseous 

 (bony) eflfusion. Such animals are often termed overgrown, from 

 the fact that their frames have outgrown their strength ; consequent- 

 ly, they are unable to bsar heavy burthens, without strain or injury 

 to the joints. The bones of horses predisposed to ossific effusion, in 

 the form of spavin, splint and ringbone, are remarkably light, i)orous 

 and brittle; and on inspecting the same, we wonder how they have 

 supported even the carcass of the animal. 



The reader has probably noticed in cattle large bony tumors under 

 the jaw, called osteosarcoma, which finally end in caries, (death of 

 the bone,) and others, located on tlie hock and on various parts of the 

 shaft bones ; these appearing without any apparent cause, illustrate 

 what I mean by ossific diathesis, or constitutional predisposition. 



We may safely conclude, therefore, that spavin originates from 

 predisposing and exciting causes, acting conjointly, or otherwise. 



Symptoms of Spavin. — These vary according to the nature and 

 intensity of the attack; yet there are some, always present, so that 

 a man of ordinary observation can readily discover the seat of the 

 lameness. 



The First is, heat and tenderness on the inside of the hock. 

 Secojidly. Inability to flex the hock with perfect freedom, the act 

 being accompanied with a sort of " catching up,'''' or sprhig-halt 

 motion. /Spring-halt is a remarkable feature of spavin, and it has 

 been noticed by several writers, Shakspeare, for example, thus . 

 refers to it : 



" One would take it, 

 That never saw them pace before, the xpavin 

 And spring-halt reigriv-d among 'em." 



Thirdly. The animal starts stiff and lame, '■^planting'''' his toe on 

 the ground, rather than the heels ; he improves, however, after a 

 short drive. 



Fourthly. The above symptoms connected with a tumor on the 

 inside of a hock, in the region of the small tarsal bones, exclude 

 all doubt. Yet the tumor, as I have just observed, is not necessary 

 to make out a case of what is technically called inter-articular 

 spavin. 



Treatiment op Spavin. — iVb man can possibly succeed in curing 

 spavin. We may palliate — relieve lameness — and hasten a?^c/^y^'9s^5, 

 (stiff joint,) and render the subject useful for certain purposes, l)ut 

 there will always exist a certain amount of stiffness about the joint, 

 which is considered unsoundness, and a hard trot will often induce 

 temporary lameness. 



In the treatment of spavin, we borrow an illustration from Nature 

 — the best and wisest of doctors — she strengthens a weak joint, by 



