WEST OF ENGLAND VETEEINARY MEDICAL ASSOCIATION, 59 
stagnating in the capillaries and veins, becomes more venous than 
it should, and otherwise unfit for the healthy nutrition of the 
tissues. It also causes a vital depression of the part, and a great 
tendency to sloughing. If, under these circumstances, the horse 
does not get exercise, the feet do not then get their natural stimulus 
from the pressure of motion, and, as the veins of the feet have no 
valves, exercise is essentially necessary to keep them in health, to 
enable them to return the blood up the leg ; for by remaining in 
one position the vessels become loaded, and the course of the blood 
in them is languid and sluggish, without any previously increased 
velocity of the blood in the arteries ; the capillaries appear to lose, 
in a great degree, their’natural tonicity; they easily dilate under 
the pressure of the blood, which, being thus retarded, accumulates, 
and is unable to overcome the obstacle of gravity; the consequence 
is passive congestion, which may be so slight as only to interfere 
with the action of the animal, causing him to go more or less 
fumbling, wooden, or as though he had lost his action ; and such a 
state may exist for months, if improperly treated, even without 
becoming more active ; it may lead to inflammation or seedy foot, 
by lessening the nutritive secretory function of the sensitive lamina, 
which in health not only supplies the horny lamina with nutriment, 
but a portion transudes into the wall in front of the lamina, so that, 
when the supply is interfered with, the fibres of the horn in front of 
the lamina become dry, and separate from the horny lamina con¬ 
stituting the disease. Should the congestion alter only slightly from 
its passive character, and continue, hypertrophy of the lamina will 
be produced, in consequence of persistent dilatation of the vessels 
of the part; exudation will also take place between the sensitive and 
horny lamina, producing more or less a sunken sole; but this pro¬ 
cess may be going on for months without producing positive 
lameness. 
Chronic passive congestion of the lamina of the fore feet may be 
so slight as only to alter the action of the animal or produce a 
slight amount of lameness ; and were it not for the ordinary sign of 
wearing away of the points of the heels of the shoes, it may be 
sometimes difficult to give an immediate opinion as to the exact seat 
and nature of the lameness. Passive congestion frequently runs on 
in a few days to active congestion, with stagnation of the blood, to 
such an extent that the vital powers become suspended, and 
sloughing of the hoof is the consequence, and this may take place 
without there being any appearance of exudation; such cases are 
more often the result of over-exertion. Laminitis arising from 
other causes does not usually take on the active form so quickly, 
and is consequently more prone to take on the exudative process, 
which is an altered and diseased action set up in the ordinary 
secretory tissues, terminating in a subacute or chronic form, with 
sunken soles or pumiced feet; or the exuded lymph may become 
changed into pus (which is one of nature’s modes of relieving herself 
from inflammation), the horny soles become softened and destroyed 
at the toe, exposing the coffin-bone to view. Subacute laminitis 
