LAMENESS IN HORSES. 
663 
Termination. — By what has been just stated, the ordinary 
termination of an attack of sub-acute laminitis has been anticipated. 
Usually, the disease, in spite of all we can do, tardily proceeds to 
produce effusion of coagulable lymph between the sensitive and 
horny laminae, which has the effect of detaching the coffin-bone 
from the hoof, leaving the latter to be forced down, by the weight 
upon it, upon the horny sole, which sinks and bulges in the manner 
afore described. Along with this detachment and descent of the 
coffin-bone there would appear to be some extravasation or con- 
gestion of blood; for when we lift up the foot and find the sole 
sunk, if the thumb be pressed upon the bulging part, a sense of 
fluctuation is imparted, leaving us to suppose that pus is collected 
underneath ; whereas if, on such a supposition, the part should be 
punctured with a lancet, blood, and not matter, issues. 'Generally, 
there is no disposition to suppuration ; nor, as was observed before, 
does this mitigated form of inflammation run into mortification. 
At the same time, let it be remembered that effusion is as well the 
termination of acute as of sub-acute laminitis ; the only difference 
being that this termination is more constant in the latter, and 
usually takes place abstractedly of the accompaniment of sup- 
puration. 
It would be altogether abhorrent to the vital operations of the body 
to suppose that the descent of the coffin-bone should create any 
vacant space within the foot. No sooner is any interval in course 
of formation between the wall of the hoof and the coffin-bone, than 
lymph is effused from the sensitive and secreting laminae to fill it 
up, and thus such effusion becomes a solid medium of union 
between the horn and the bone ; and, in the course of time, by 
degrees, changes take place in it, converting it, firstly, from lymph 
into a fibrous substance of the nature of cartilage, a sort of callus ; 
and subsequently into fibro-horny substance, which as time elapses 
approaches nearer and nearer to the nature of horn ; though it 
never, I believe, quite acquires the dense compact texture of 
the old wall of the hoof, and on that account is to the latest 
periods of life generally at sight distinguishable from it. This 
established deformity of foot it is that constitutes what is called 
'pumice sole. 
The Causes of Sub-acute Laminitis are not always evident. 
There can be no doubt but that certain descriptions of feet, such as 
large and flat and weak feet, are from their conformation predisposed 
to the disease, on the same principle as they are to acute laminitis. 
As one sort of foot is predisposed to navicularthritic disease, so is 
another to disease of the laminae; and therefore it is that the excitant 
— which, in both instances is, in one comprehensive word, work — 
likely to produce laminitis in one case, navicularthritis in another, 
according as the foot to which it is applied be of this or that 
