DISEASES OF HORSES 273 



parts a profuse, thin, fetid, watery discharge, which gradually under- 

 mines and destroys the surrounding horn, until a large part of the 

 sole and frog is diseased. The living tissues are swollen, dark col- 

 ored, and covered at certain points with particles of new, soft, yel- 

 lowish, thready horn, which are constantly undergoing maceration 

 in the abundant liquid secretion by which they are immersed. As 

 this secretion escapes to the surrounding parts, it dries and forms 

 small, cheesy masses composed of partly dried horny matter, exceed- 

 ingly offensive to the sense of smell. When the disease originates 

 independently of an injury, the first evidences of the trouble are the 

 offensive odor of the foot, the liquid secretion from the cleft and 

 sides of the frog, and the rotting away of the horn of the frog and 

 sole. 



In the earlier stages there is no interference with locomotion, 

 but later the foot becomes sensitive, particularly if the animal ia 

 used on rough roads, and, finally, when the sole and frog are largely 

 destroyed the lameness is severe. 



Treatment. Since canker does not destroy the power of the 

 tissues to produce horn, but rather excites them to an excessive pro- 

 duction of an imperfect horn, the indications for treatment are to re- 

 store the parts to a normal condition, when healthy horn may again 

 be secreted. The old practice of stripping off the entire sole and 

 deep cauterization, with either the hot iron or strong acids, is not 

 attended with uniformly good results. 



It is believed that recovery can generally be effected as surely 

 and as speedily with measures which are less heroic and much less 

 painful. True, the treatment of canker is likely to exhaust the 

 patience, and sometimes the resources, of the attendant; but after 

 all success depends more on the persistent application of simple 

 remedies and great cleanliness than on the special virtues of any par- 

 ticular drug. 



First, then, clean the foot with warm baths and apply a poul- 

 tice containing powdered charcoal or carbolic acid. A handful of 

 the charcoal or a tablespoonful of the acid mixed with the poultice 

 serves to destroy much of the offensive odor. The diseased portions 

 of horn are to be carefully removed with sharp instruments, until 

 only healthy horn borders the affected parts. The edges of the sound 

 horn are to be pared thin, so that the swollen soft tissues may not 

 overlap their borders. With sharp scissors cut off all the prominent 

 points on the soft tissues, shorten the walls of the foot, and nail on 

 a broad, plain shoe. The foot is now ready for the dressings, and 

 any of the many stimulating and drying remedies may be used; but 

 it will be necessary to change frequently from one to another, until 

 finally all may be tried. 



The list from which a selection may be made comprises wood 

 tar, gas tar, petroleum, creosote, phenic acid ; sulphates of iron, cop- 

 per, and zinc ; chloride of zinc, oichloride of mercury, calomel, caus- 

 tic soda, nitrate of silver, chloride of lime ; carbolic, nitric, and sul- 

 phuric acids. 



