DISEASES OF DOMESTIC ANIMALS. 101 



chance for successful treatment ; but if higher, and there is much heat in 

 the joint, it is much more tedious to treat. It may be produced by inflam- 

 matory action set up principally in the periosteum, and in some cases a 

 comparatively trivial cause ; but if the lameness is more severe, it is likely 

 the inflammatory action is set up in the internal part of the bones. 

 There is an exudation thrown out between the bones, and also between 

 the periosteum and the bones, and sometimes complete anchylosis of the 

 articulations is the result. Spavin may involve more or less of the entire 

 gliding articulation, or even the entire articulation. You may have 

 anchylosis of the cuneiform bones without any external deposit. 



Causes are predisposing and exciting. The first are either constitu- 

 tional or local. There may be an ossific diathesis, or from the formation 

 of the hock. A narrow hock from before back, and a long metatarsal 

 bone, predisposes to it. The exciting causes are hard and fast work ; 

 driving a young horse fast upon hard roads, especially if not in a fit con- 

 dition ; or a severe strain, setting up irritation in some of the little inter- 

 osseous ligaments, extending and involving the entire joint ; and it is 

 sometimes the result of undue weight upon the limb. Anything that will 

 set up concussion will produce it. Shoeing is said to be a cause, as with 

 high-heeled shoes extreme flexion causes irritation of the cuneiform bones, 

 and proves an exciting cause. Eeceiving an injury to the foot, causing 

 the weight to be thrown on the sound limb for eight or ten days, pro- 

 duces concussion, and spavin results. Hence the necessity for using 

 slings in cases of injury. 



Symptoms. — If it is large it is easily detected. But we sometimes meet 

 a case of lameness where the inflammation is going on and there is no 

 enlargement. Look at the natural hock ; look at the bones in their natu- 

 ral condition - at their natural prominences — and endeavour to become 

 conversant with the natural appearances of the hock in a healthy animal. 

 There are certain prominences under the malleolus, and they vary in size 

 during health — in some small, in others larger— and it is not a bad sign 

 to see them well developed. The lameness, in most cases, precedes 

 the exostosis. The lameness is characteristic, and is best seen when the 

 animal is first brought out of the stable. After driving for some dis- 

 tance it will, perhaps, disappear, and will show no more lameness during 

 the day. And sometimes there are cases where the exostosis attains 

 a considerable size without the horse being much 'ame. A pretty 

 good way of detecting it is by the eye (but this will not do to rely 

 on in all cases). Make him stand square upon the limb, and throw 

 his weight upon it, and stand just to one side of the horse in front, 

 and take a look from the internal malleolus down, and look through 

 between the fore legs from behind, etc. But just standing about eighteen 

 inches to one side the horse's head is a very good position, and then draw 

 the hand carefully over the hock. If it is the left leg, just pass the right 

 hand down over the hock, and you may detect a bony enlargement and 

 heat in the parts. If the animal is standing, he will flex the limb to 

 some extent. In a case of long standing there are other changes. The 

 whole nutrition of the limb is affected, and there is casting of the 

 muscles of the haunch ; and this may mislead and cause you to think 

 this is the cause of the lameness. He walks upon the toe to a great 

 extent. Turning the horse from side to side will assist you in determin- 

 ing the seat of lameness. If it is slight you must judge, to a great 

 extent, by the action of the animal, and you must be careful if the horse 

 has a very large spavin, and becomes suddenly lame, for it may be that 

 the animal has picked up a nail, and in such a case you may overlook the 

 true seat of the lameness — more especially if he is extremely lame. It is 



