170 DISEASES OF THE FEET. 



SYMPTOMS. — ^The diseased portion of the membrane which, 

 during health, performs the function of manufacturing sound horn 

 for the sole or frog, secretes at first a degenerate cheese-like 

 material which assumes, later on, the character of a thin, stinking, 

 and nearly colourless discharge; and its surface becomes studded 

 over with pale, fungoid growths. The sole becomes gradually 

 undermined on account of the extension of this diseased action, 

 which, in most cases, commences at the frog, and sometimes 

 extends to the wall of the hoof. It may, however, begin by an 

 inflammatory condition of the skin at the back and lower part of 

 the pastern, i.e., from grease. The progress of canker is generally 

 very slow. A noticeable characteristic of canker is the comparative 

 painlessness of the disease. 



CHANCES OF RECOVERY.— MoUer points out that cases of 

 canker are serious, proportionately to (1) the rapidity of their 

 course ; (2) thinness of the discharge ; (3) implication of the sen- 

 sitive laminae ; and (4) number of feet affected. Although canker 

 is a tedious disease to treat and demands skill and great patience, 

 it is, even in bad cases, generally susceptible to cure. 



PREDISPOSING INFLUENCES.— The tendency of a horse's feet 

 to contract canker appears to be proportionate solely to the amount 

 of their exposure to the action of wet, dirt, general neglect and 

 injury. The hind feet are more often involved than the fore, seem- 

 ingly because they suffer more frequently from unsanitary in- 

 fiuences. I do not think that its occurrence is in any way in- 

 fluenced by breed, conformation, or general health. The fact that 

 it is seen much more in common cart horses than in well bred ani- 

 mals, may be accounted for by the former being more exposed to its 

 predisposing influences than the latter. Modem improvements in 

 stable sanitation have been followed by a well-marked decrease 

 in the frequency of canker. 



NATURE AND PRINCIPLES OF TREATMENT— The fact 

 iliat although purely local treatment can in almost all cases effect 

 a cure, constitutional treatment is powerless to arrest its progress, 

 proves that it is a local and not, as averred by some authorities, a 

 constitutional disease. Two special characteristics of the inflam- 

 mation of canker are the infectious influence of its discharge on 

 neighbouring parts of the membrane, and the fact that a diseased 

 spot can be cured only by the removal or destruction of tlie in- 

 volved tissue, or by rendering it thoroughly free from putrefaction, 

 which we may do by the use of antiseptics. The consideration of 

 tliese characteristics suggests the parasitic nature of the disease, 



