806 
DISEASES OF THE FOOT. 
tense in consequence of the weight on them, tends to rotate the os pedis 
around its transverse axis, and so to cause the toe to sink and the wings 
to rise. In proportion as the toe of the os pedis recedes from the wall, 
the surface of the sensitive laminae becomes thickened, until finally it 
may measure ten times its normal thickness. This thickening consists 
essentially in an increase in the white line, as can afterwards be distinctly 
seen on examining the under surface of the hoof. As the point of the 
os pedis moves downwards, the horn of the sole at the toe necessarily 
becomes flattened, and finally takes a convex form. This condition, in 
connection with certain changes in the horny wall, is termed “dropped 
sole.” It was formerly assumed that the inflammatory growth pressed 
the os pedis downwards. Dominik insisted, on the other hand, that the 
horn of the toe was dislocated upwards, but that the os pedis remained 
in its normal position. Neither view harmonises with our present views, 
and to-day no doubt can exist that Siedamgrotzky’s explanation is 
correct. The continuance of this abnormal form of hoof is dependent 
on the pressure of the ground against the toe of the hoof whilst the 
animal is moving. In dropped soles the wall of the toe close below the 
coronet appears abnormally perpendicular, but near the bearing surface 
takes a more horizontal direction, whilst the bearing surface itself is not 
only longer but also more oblique. This abnormal formation of hoof is 
identified with chronic laminitis. 
The severe pain sometimes forces the animals to lie continuously, 
when death usually results. In other cases, the os pedis perforates the 
horny sole, purulent or septic inflammation of the sensitive structures of 
the foot sets in, pain increases enormously, the animal is unable to stand, 
and death occurs from pyaemia. 
Causes. Laminitis is most common in badly-formed, flat, and pointed 
feet. Its onset is favoured by mechanical irritation of the sensitive 
structures, resulting from severe work at high speed, from continuous 
standing, as a result of painful lameness, from unskilful shoeing, &c. 
Eapid work, after prolonged confinement to the stable, is a very common 
cause of the disease. Laminitis is also very common during and after 
long sea voyages, as animals can seldom be exercised when in transit, 
and their digestive system is very apt to become disordered. Chill 
increases the tendency to the disease, which is therefore more frequent 
at the time of shedding the coat, after exposure to wet, or after long rest. 
The external causes comprise errors of diet and chill. Heavy foods, like 
rye, wheat, and barley, especially when given new, are particularly 
dangerous; but new oats and new hay also produce laminitis. At 
present it is not quite clear how such foods act, but the fact that boiling 
and steaming seem to diminish the injurious effect, points to the action of 
a micro-organism or its toxin, and contradicts the view that the attack 
