524 THE DISEASES Ol' THE HORSE 



received the name of bog-spavin and thoroughpin ; but tliey also occur at 

 the fetlock and knee joints ; in the former case being sometimes confounded 

 with windgalls, which are inflamed bursie mucosre (see "Windgalls). 



BoG-SPAViN is very ajft to attack young horses when they are overworked 

 before being fully seasoned, but it may occur at all ages. It shows itself 

 at the inner side of the joint, because here the ligaments are wider apart, 

 and there is more room for distension. Its seat is the capsule between the 

 tibia and astragalus, which is here unprotected by any strong fibrous 

 co\ering, and readily yicUls to the gradual pressure of the secretion from its 

 internal surface (see Fig. 58, G H, page 425). 



Thoroughpin maybe either an increased secretion of the synovial capsule, 

 between the astragalus and os calcis, or between the scaphoid and cuneiform 

 bones, or of the bursa mucosa lying between the tendo Achillis and the 

 tendo perforatus. In the first of these cases it often coexists with bog- 

 spavin, and the synovia may be made to fluctuate from one bag to the other, 

 the only line of demarcation being the astragalo-calcanean ligament (see 

 Fig. 58, G, page 425). 



Both bog-spavin and thoroughpin may exist, or either separately, without 

 occasioning lameness ; but where they are just established, there is generally 

 some small degree of active inflammation, which causes a slight lameness on 

 first going out of the stable, but soon disappearing. 



The 'Treatment should be by pressure, kept up for a long time, by means 

 of a carefully-adjusted truss. Failing success by pressui'e, a blister-charge 

 and a long rest may succeed. These are made of pitch, resin, and bees-wax 

 with the addition of a small quantity of cantharides or Si)anish fly. They 

 are applied hot and covered with chopped tow or wool, which prevents the 

 bedding from sticking to the part when the horse lies down. A slight 

 amount of irritation of the skin is produced and some effusion under it, 

 which acts as a cushion ; the contraction and pressure of the charge acts 

 for a considerable time as a bandage, as it does not as a rule come off 

 until the hair of the part is moulted. 



Line firing is also adopted for the production of a permanent support, as 

 wherever the lines heal up a new and inelastic tissue takes the place of true 

 skin, but this should only be resorted to when other measures have failed ; 

 it should be done thoroughly if done at all, the whole hock being covered. 

 These dropsical conditions are successfully treated b}' an operation for the 

 removal of the redundant fluid by an aspirator, under aseptic conditions, 

 and an injection of a special preparation of iodine. 



Delicate young foals are subject to a rheumatic inflammation of their 

 synovial membranes, specially displayed in the knees and hocks, and 

 apparently caused by exposure to cold. It seldom goes on to produce dis- 

 organization of the cartilages, but the capsular ligaments are distended with 

 thin yellow synovia, causing considerable stiffness. The cellular tissue 

 around the joints also becomes edematous, and the legs fill all the way 

 down to the feet. It is commoidy known among breeders as the "joint 

 evil," and though in itself it is not dangerous, yet it marks the existence of 

 constitutional weakness which is likely to occasion some more fatal malady. 

 The Treatment should consist in attending to the general health by 

 strengthening the mare, which is best done by giving her a drachm of 

 sulphate of iron in her corn twice a day. The joints of the foal should be 



