CANKER. 443 



that all four feet turn out affected ; and, when this is the case, 

 it proves extremely difficult and tiresome to get quit of the 

 disease, the healing of one foot being so apt to be followed by 

 fresh eruption in another. 



The Symptoms of Canker — in other words, the appear- 

 ances presented by a foot in a state of canker — are at once pe- 

 culiar and striking. The diseased foot assumes that strange loath- 

 some aspect which may suggest a fanciful comparison of it to 

 a crab or a toad, or any other unsightly or anomalous thing. It 

 looks as though it hardly belonged to the limb ; as though, in fact, 

 it never could have been included within the confines of the hoof. 

 With its fungous excrescences sprouting from it, wherever it 

 happens to be bare of hoof, it conveys to our mind a notion that 

 it is in a state of luxuriance or hypertrophy. This is sup- 

 posing we do not see the foot until canker be fully developed in 

 it. Had we happened to have inspected it at the beginning, or 

 could we obtain the history of the case, we should almost in- 

 variably find that the germs of the disease were first discover- 

 able within the cleft of the frog. This cavity becomes the 

 fomes of corruption and decay. At its bottom and around its 

 sides are visible shreds of dark-coloured, deadened, loosened 

 portions of horn, which have become detached from the living 

 surfaces beneath, through an acrid serous exudation from the 

 latter, seen everywhere oozing out amid the crevices of the 

 rotten and semi-detached hoof. The partial solution of this dead 

 horn it is that has in places rendered the fluid black, and, from 

 its becoming at the same time putrescent, intolerably offensive 

 to the smell. 



When we come to remove the discoloured and decayed horn, 

 and to expose the sensitive surfaces, we find the latter covered 

 with an opaque whitish caseous matter, supplying the place of 

 what naturally should be fresh-secreted horn ; but which is evi- 

 dently in important respects different from it, no less in its aspect 

 than from its property of continuing softness, and consequent un- 

 fitness for the purposes of cover and protection to the living sur- 

 faces. No sooner, however, is the resistance or pressure afforded 

 to the secreting parts by the old horn (so long as it remains) 



