; 193 
that the bones of the true hock joint do become implicated, as the disease 
spreads ; but it is not by any means a common occurrence. One will 
readily understand that the higher the bony growth is deposited, the more 
grave are the consequences. On the other hand, when seated lower down 
between the canon bone and the little bone immediately above it, the 
cementing together of the joint is not of great moment. The progression of 
the animal in this case is not much affected thereby, as there is but little 
‘motion in this joint. The causes of spavin are of two kinds, actual or 
external, and predisposing or internal. 
There are a number of predisposing causes, which we may briefly 
consider. Firstly, the bones of young and overgrown horses being soft and 
immature, are more liable to become diseased. One can readily understand 
that, at an early age, the bones and their coverings, as well as the joints and 
ligaments, are most liable to become diseased, especially wheri the animal 
is heavily weighted, before his bony tissues are really consolidated. Secondly, 
irregular conformation of the hock joint is also to be regarded as a 
predisposing factor in the causation of spavin. When the angle of the hock 
is less than 135°, the animal is termed “ sickle-hocked.” Such a conformation 
of hock we mentioned was unsuited for rapid progression, and is especially 
liable to curb. Likewise it is believed to be more liable to become the seat 
of spavin, though the predisposition to this disease is not so marked, as in 
the case of curb. Wide hocks, sometimes caused by bad shoeing, or disease 
of the fetlock joint ; straight hocks, in which the angle of the joint is more 
than 160°; and cow hocks are also examples of irregular construction of 
these parts. We do not know that these latter irregularities increase the 
liability to spavin. Animals: with “laced-in hocks” or “tied in below ‘the 
hock” are also especially subject to spavin; and this is also the case in 
animals with short or round hocks. Thirdly, excitable animals of irritable 
tempérament, it is believed, are also more subject to contract spavin. Fourthly, 
animals with long backs and narrow hind quarters, are more prone to the 
osseous disease of the hock in question. Lastly, hereditary predisposition is 
very marked in this inflammatory disease. 
The actual causes of spavin are strain or concussion of the structures 
of the joint, due to galloping, or very hard work, or wearing shoes with too. 
high calkins, and imperfect food supply. Necessarily, if the food is. 
insufficient and of bad quality, the animal will be more subject to spavin, 
and, indeed, also to sprains of the various muscles and tendons of the body. 
It is in cart-horses that high calkins not uncommonly are answerable for the 
production of spavins; and this is especially the case, when the animal is 
employed for drawing heavy weights down hill. It is necessary that animals 
employed for hunting should have well formed hocks, because the amount of 
concussion on the hocks in leaping renders them more liable to suffer from 
spavin, and one rarely sees an animal which has been hunted for a couple of 
seasons without observing that he has thrown out spavins. It is not strange 
‘that the more forward the spavin appears, the greater is the resulting 
impediment to the progression. 
oO 
