216 
MR DICK ON THE CAUSES AND PREVENTION 
logcus. Ibis is also frequently the cause of disease in the feet 
cf oxen cr milch cows, which have been kept standing for a 
long period in the cow-house. The laminated structure by w T hic*h 
the crust in the sheep’s foot is connected, like that cf the 
hoofs of horses, having been inflamed, and that inflammation 
kept up by'the continuation of the causes which originally ex¬ 
cited ii", there is produced a change in the structure from which 
the hoof is formed; and, there being a diseased secreting organ, 
of course a diseased secretion of horn is produced. We have 
therefore a loose spongy horn secreted, which, from the open¬ 
ness of its pores, admits the particles of earth and moisture 
more freely than before, and these are also at the same time 
more securely lodged by the rapid grow th and overshooting of 
the crust, until, by the cominued irritations upon the quick, 
they soon cause a discharge of matter. This matter from the 
inflamed part, by mixing with the moisture of the ground and 
the particles of earth, increases more rapidly the destruction of 
the whole foot. 
The progress of the disease is not equally rapid in every in¬ 
stance. Sometimes it seems to go on to a certain extent, and 
the foot may again, in a considerable degree, recover. All the 
feet of the same animal are not equally affected, the fore ones 
being most liable to the disease. Sometimes there is only one 
of the feet affected, but that is most commonly a fore one. 
At times I have found only one of the digits of the foot affected; 
and, in some, from the hoof having been broken short off*, I 
have found one of the toes recovered, while the other toe con¬ 
tinued diseased. 
In the first stage of the disease there is only found a little 
overshooting of the edge of the crust, which seems either to be 
overgrown and bent in upon the sole, or the edge of the crust 
is forced asunder from the sole by a w edge of earth, which, by 
the pressure alone betw een the crust and the laminated struc¬ 
ture, produces inflammation. With this the sheep becomes 
lame, and the disease spreads rapidly. In the other case, the 
crust or edge of the hoof continues to grow until it envelopes 
the sole, and ledges matter, as has been already stated. The 
softening of the horn of the sole, from these causes, soon excites 
that inflammation which detaches the hoof*, and produces the al¬ 
terations in the secreting surface which constitute the disease. 
Nature, however, is bountiful in her provisions. The inflam¬ 
mation which is set up is not generally of the mrst active or 
acute kind; for it would appear that, instead of the inflamma¬ 
tion being raised to that pitch w hich would at once throw off* 
the hoof, there is, for a time, most commonly rather an increase 
