286 HEALTH AND DISEASE 



Causes. — Tliese are predisposing and exciting. Most if not all subjects 

 of this affection inherit a constitutional condition which predisposes them 

 to suifer when exposed to one or another of the various exciting causes. 

 Of these the principal are exposure to wet, and cold easterly and north- 

 easterly winds, hard and continuous work, sprains, concussions, blows and 

 other injuries to the joints, inHuenza, and strangles. 



Symptoms. — The disease may be confined to a single joint, but more 

 often it invades two or more. The large joints, as the knee, the hock, the 

 stifle, and the fetlock, are those most frequently in\'olved. In its chronic 

 form rheumatic arthritis commences with stiffness, observed more particu- 

 larly after exertion. For some time it may continue without materially 

 interfering with the animal's movements. Then a slowly progressive enlarge- 

 ment ajDpears — at first resulting from distension of the capsular membrane 

 with synovia, but later the bones of the joint throw up irregular nodular 

 swellings around and about their articular ends, and these, encroaching on 

 and irritating the surrounding ligaments and tissues, provoke additional 

 enlargement. Pain and lameness are now more or less marked, and the 

 action of the affected joint becomes not only restricted but difficult. 



In long-abiding cases the cartilage may be removed from the articular 

 ends of the bones, whose rough surfaces, when brought into contact with 

 each other, impart to the hand and the ear a crepitating sensation or sound. 

 In this disease there is no tendency to the formation of abscess, but the 

 morbid action is expended in provoking enlai'gement and condensation of 

 the extremities of the bones and tissues connected with the joint. 



Treatment. — In this connection much importance attaches to an early 

 recognition of the disease, when a dose of physic, followed by a short course 

 of iodide of potassium, and a brief rest, will usually check its jjrogress. 

 Where it has been allowed to advance so far as to produce considerable 

 swelling, massage and friction should be freely applied to the joint two or 

 three times a day, and in the intervals it should be enclosed in a warm 

 flannel bandage. The food should include a liberal amount of carrots or 

 other succulent roots or grasses, with bran and a small ration of scalded 

 corn and sweet hay. 



With this may be given an ounce of linseed-oil night and morning, with 

 a full dose of iodide of potassium and carbonate of potash. If the joints 

 are very painful they may be anointed with belladonna liniment twice 

 a day. Should this not have the desired effect, a mild iodine blister 

 repeated at short intervals may yield good results. 



Horses giving evidence of this affection should have a dry lair and be 

 protected as far as possible from cold and wet, especially while heated. 



