444 CANKER. 



removed ihsin fungus sprouts up from the denuded and exposed 

 surfaces. 



Fungus, which may be said to constitute the essence of 

 canker, is a white, soft yet consistent substance, of fibrous com- 

 position, growing in such exuberance from the diseased parts 

 that it not only occupies the place of the horny covering, but 

 swells to a bulk much beyond the ordinary growth of the hoof, 

 having its surfaces covered with layers of the white caseous 

 matter but now mentioned, while its fibres and crevices are 

 bedewed with the offensive ichorous secretion which, from the 

 solution of the old horn remaining, turns black around its roots. 

 From the granulary aspect the fungus ordinarily assumes, some 

 have regarded it as a sort of exuberance of granulation issu- 

 ing out of the keratogeneous or secretory tissue; while others, 

 from its extreme vascularity and liability to bleed when 

 maimed or cut, have viewed it of some such nature as fungus 

 hcematodes. Neither of these hypotheses will, however, bear 

 examination. In an interesting paper written by M. H. Bouley 

 on the subject of crapaud (canker) in the Recueil de Med. Vet. 

 for January 1851, he has given it as his opinion, that the fibres 

 of the fungus are nothing more than prolongations of the villosi- 

 ties of the sensitive tissue of the foot in a state of hypertrophy , 

 bundles of which matted together in close union constitute the 

 masses of fungus. And in confirmation of this opinion, he ad- 

 duces the fact of fungus proving to be longest and most fibrous 

 and luxuriant in situations where the villosities of the foot 

 (which are the organs of touch) are known to be the most de- 

 veloped, such being the circumferqnt border of the coffin bone 

 and the inflexions of the bars at the heels ; whereas, in places, 

 such as the body of the frog and the sole, where the same de- 

 velopment of villosity is not met with, the fungus is compara- 

 tively short and close in texture, and indistinctly fibrous. And 

 M. Bouley adds, that, as in the normal state the villosities never 

 exceed a certain longitude in consequence of the wholesome 

 restraint they meet with in their growth from the hoof covering 

 them, so is this hypertrophic development or morbid growth of 

 them to be attributed to the loss of such wholesome or normal 



