DISEASES OF THE HOKSE. 393 



animal susceptible to infection; but neither the injury nor the irrita- 

 tion and inflammation of the tissues which follow are sufficient to 

 induce the disease. 



For some unknown reason horses with lymphatic temperaments — ■ 

 thick skins, flat feet, fleshy frog-s, heavy hair, and particularl}- with 

 white feet and legs — are especially liable to cankor. 



Si/niptoms. — Usually, canker is confined to one foot; but it may 

 attack two, three, or all of the feet at once; or, as is more cominonl}^ 

 seen, the disease attacks first one then another, until all may have been 

 successively afl'ected. When the disease folloAvs an injury which has 

 exposed the soft- tissues of the foot, the wound shows no tendenc}^ to 

 heal, but, instead, there is secreted from the inflamed parts a profuse, 

 thin, fetid, watery discharge, which gradually undermines and destroys 

 the surrounding horn, until a large part of the sole and frog is diseased. 

 The living tissues are swollen, dark colored, and covered at certain 

 points with particles of new, soft, yellowish, thready horn, which are 

 constantl}" undergoing maceration in the abundant liquid secretion by 

 which they are immersed. As this secretion escapes to the surround- 

 ing parts, it dries and forms small, cheesy uiasses composed of partly 

 dried horn}^ matter, exceedingly offensive to the sense of smell. When 

 the disease originates independently of an injury, the first evidences 

 of the trouble are the oflfensive 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 is used on 

 rough roads, and, fi.nally, when the sole and frog are largely destroj^ed 

 the lameness is severe. 



Treatnient. — Since canker does not destroy the power of the tissues 

 to produce horn, but rather excites them to an excessive production 

 of an imperfect horn, the indications for treatment are to restore the 

 parts to a normal condition, when healthy horn may again be secreted. 

 In my experience, limited though it has been, the old practice of strip- 

 ping off the entire sole and deep cauterization, with either the hot 

 iron or strong acids, is not attended Avith uniformly good results. 



I am of the opinion that recover}' can generally be effected as surel}'^ 

 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 

 particular drug. 



First, then, clean the foot with vrarm baths and applj^ a poultice 

 containing powdered charcoal or carbolic acid. A handful of the 

 charcoal or a tablespoonful of the acid mixed with the poultice 



