58 WEST OE ENGLAND VETERINARY MEDICAL ASSOCIATION. 
when studied under the microscope. In order to become acquainted 
with the elements of this process, we must analyse the condition of 
the vessels and the blood, for which purpose I refer those who desire 
to know more on the subject to the works of Paget, Lister, Wharton 
Jones, and others. 
In laminitis arising from fat and idleness, which is the common 
cause, there must be this state analogous to passive hypersemia, and 
under the microscope you would find the capillaries tortuous, 
varicose like the following sketch, jamming up the circulation at or 
nearest the coats with blood-discs, the current proceeding through 
the centre onward, comparative stasis occurring at the circumfer¬ 
ence. The fibrine and solid constituents of blood are also materially 
increased bv over-feeding and insufficient exercise, and hence another 
cause of stagnation. 
The loss of tone would, in my mind, be thus caused—by the 
perpendicular position of the animal and over-feeding, producing 
increased specific gravity of blood, thus inducing or tending to 
induce stasis. 
In the case of horses thus affected the vessels quickly acquire 
their original tonicity and proper dimensions as soon as the strain, 
arising from determination of blood, is diminished by exercise ; 
convalescence is then speedy, and restoration of the part complete. 
I am informed by a medical friend (Mr. Freeman) that the same 
morbid states might be produced in the human nail as in the horse’s 
hoof, viz. stasis, exudation of an inflammatory character, and death 
of the part, by precisely the same means as they are produced in 
the horse—that is, the keeping of the arms and hands hanging 
down for a considerable period without muscular movement would, 
in a modified degree, produce laminitis, or something akin to it, 
ending in the destruction of the nail; and this would be caused 
precisely by the same pathological process as that in the hoof of the 
horse. When the human nail begins to die, it dies rapidly, and 
this only when the root is concerned ; nails sometimes recover 
themselves, when a fair half of the nail is found healthy at the 
beginning of treatment. If you tie a string, or make pressure in 
any way, upon the root, which nourishes and produces the nail, as 
well in the human body as in the horse,’excessive pain is a conse¬ 
quence, nutrition of the developed nail fails, and, if the pressure is 
continued, it drops off; and so in the same way, if there is no pres¬ 
sure, the total absence of that necessary muscular movement of 
exercise, in the horse, producing the same result, viz. indirect blood 
stasis, terminating in laminitis. 
Pathology. —In general plethora every part is preternaturally full 
of blood, and the blood itself is full of the elements of nutrition. 
General plethora, therefore, implies, in one sense, local plethora of 
every organ and tissue ; the tissues, in virtue of their nutritive 
power, exercise an influence on the movements of the blood ; in 
active hypersemia their attractive force is increased, and it is in part 
through the failure of this nutritive power that congestion takes 
place, also the altered condition of the blood itself, which, semi- 
