80 CAUSES, SYMPTOMS AND TREATMENT OF 



the union between the earthy salts and the vascular net-work in which 

 they are contained is lessened, and the salts are partially removed and 

 the place taken by the products of inflammation. Then there is a 

 cancellated tissue, and it enlarges to a certain extent, and when the 

 inflammatory action begins in this is always the case. The inflam- 

 mation may come in the cancellated tissue and involve the compact 

 and destroy the laminal layer. This destroys the articular cartilage, 

 then the cancellated tissues come in contact. Nature endeavors to 

 overcome this by throwing out a deposit, and the joint becomes one 

 bone. If the inflammatory action results from some constitutional 

 cause, it is scrofulous or rheumatic ostitis, which is more likely to ap- 

 pear in colts. This inflammation may also have different termina- 

 tions and names. Kesolution may be a termination ; or if the inflam- 

 matory action is kept up, an abscess may result — and an abscess of 

 the bone is difficult to detect in our patients. If there is but a small 

 amount of pus, it is usually relieved by cutting open the parts, treph- 

 ining, etc. An injury may produce an abscess. The horse suffers in- 

 tensely from inflammation of the bone ; the periosteum is very likely 

 to become affected, periostitis and ostitis frequently being associated ; 

 an exudation is often thrown out between the periosteum and the bone, 

 as in splint, sore shins, etc., just from inflammation of the periosteum. 

 Periostitis is more likely to occur in those bones that stand upright, 

 and is due to concussion. These are the products of inflammation of 

 the bone. If ossitic matter is thrown out it is called exofosis, meaning 

 bony deposit, and is produced by more or less inflammatory action. 

 A very slight action is sufficient, sometimes, to produce it. It may 

 occur without the horse suffering from irritation. This is sometimes 

 spongy, and sometimes hard and dense. A common exostosis is 

 spavin, and it is analagous to the structure of bone, from which it 

 sprung. It is in our patients generally the result of injury. Splint 

 is perhaps a better example of exotosis than spavin. 



Caries is analagous to ulceration in the soft tissues — death of bone 

 in small particles It is decay of bone, the result of inflammatory ac- 

 tion. It is molecular death of a part. Caries is more common in 

 some bones than others. In spavin, where the animal has been lame 

 for some time, the bone presents a carious condition ; also in ringbone, 

 navicular disease, etc. It seldom in such cases affects the soft tissues 

 to any great extent, and is called dry caries. The laminal layer under- 

 goes absorption and ulceration, and the articular cartilage is destroyed, 

 and is never renewed. Inflammation is set up in the bone from some 

 cause or other ; nutrition is interfered with ; a change takes place be- 

 tween the vascular elements, and the salts are removed to a certain 

 extent, and there appears a small spot upon the articular surface. If 

 it attacks other parts, as from injury to facial bones, or in connection 

 with the atlas, withers, etc., then it is somewhat different ; matter is 

 formed and cannot escape, and it burrows down and sets up irritation 

 in the periosteum and bone, and so produces caries of the bone. If 

 there is a discharge, and it continues for some time, it is generally 

 fetid. There may be caries of the lower jaw, which may be caused by 

 the action of the bit. If the inflammatory action throws out ossific 

 matter sufficient to fasten two bones together, it is called 



Anchylosis. — This is classified under bone diseases, but it is the 

 result of long union ; but it may be due to fibrous structures thrown 

 out from the ligaments, tendons, etc. But if it involves the hock 

 or pastern joint, then it is generally from ossific matter thrown out 

 between the articulations. If the bone becomes inflamed, causing 



