LAMENESS IN HORSES. 
244 
lations issuing 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 as his opinion that the fibres of 
the fungus are nothing more than prolongations of the villosities 
of the sensitive tissue of the foot in a state of hypertrophy , 
bundles of which matted in close union together 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 circumferent 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 certain dimensions 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 this wholesome or normal 
restraint. The same thing happens, under other circumstances, 
in cases in which we are desirous to promote the formation of 
healthy horn. Without pressure we well know how difficult 
this often is to accomplish, and at the same time maintain the 
growth within proper bounds. And what further favours this 
view of the matter is, that fungus is never seen in situations 
where villi or villosities are indemonstrable, such as upon the 
surfaces of the laminae. 
It might be expected, that, since the fibres of the fungous 
growth consist, in point of fact, of hypertrophic villi, the fungus 
itself would prove a highly sensitive substance ; whereas, so 
far from this being the case — though it be so vascular that it 
bleeds freely from slight injury — every practitioner well knows 
that it possesses no, or but extremely little, sensibility. Indeed, 
the animal himself shews this by the manner in which he steps 
upon it, and the extent to which he can (through the dressings) 
endure pressure upon it. This loss or want of sensibility 
M. Bouley accounts for, by the thick coating of fibro-plastic 
matter in which the villi are included in the course of their in- 
creased development, and which really, as it were, isolates the 
nerves from all surrounding impressions. 
Canker is tardy in its Progress in general. Though, 
