18 
the heart beat is almost inaudible, respiration is scarcely perceptible, 
consciousness is lost, and the body is icy cold. The vitality in this 
condition is very limited; the first effect of too great cold is to 
diminish the vitality of the part to which it is applied. The capillaries 
of the part are strongly contracted so that a limited quantity of blood 
flows through the part. Nutrition is thereby impaired or may even be 
entirely suspended; if there is an entire suspension of the nutritive 
process, gangrene will of necessity follow, for there has been a destine 
tion of the vitality of the part. Since all functional activity is 
exhausted by over exertion for a lengthened period of time, the 
capillaries after having been strongly contracted for a season, undergo 
paralysis and are distended with blood. In some instances the capill¬ 
aries never regain their power of contracting and evei lemain 
dilated. This condition of the capillaries will frequently be noted in 
frost-bitten noses—the nose ever presenting a red or reddish blue 
appearance. Too great cold will cause vesicles to laise on the suiface 
of the body as well as too great heat. These vesicles differ from those 
caused by heat, in that the serum which they contain is usually bloody. 
When a part of the body becomes completely frozen, it will snap off 
like a pipe stem or piece of glass. Subjection to a low tempeiature 
may cause complete depilation in the horse without raising a vesicle. 
Tn the winter of 1875, a young black gelding that had been laid upfoi 
two weeks from scratches, was taken out one day befoie a sleigh when 
the temperature stood at zero; after about two hours exeicise, pait of 
which was fast, and the rest slow, he was returned to his stable and 
‘warmly clothed, as he had been clipped some three weeks before; in 
twenty-four hours time he showed signs of indisposition, and in six 
days was naked except the limbs, mane and tail. The horny layer of 
the epidermis peeled of with the hair, and the exudation into the skin 
gave it a thickened velvety feel. What caused the hair to fall off ? 
Was it the direct action of the cold on the hair, or were the blood¬ 
vessels supplying the hair bulbs so strongly contracted by the cold, for 
a length of time sufficient to destroy the vitality of the liaii, because 
of the absence of nutrition ? The loss of the coat never seemed to 
injure the animal in any way, and in a few weeks time was replaced 
by a new one. 
Frost bites occur most often in veterinary practice upon the legs 
of horses worked in cities, where salt is placed upon the snow and ice 
to melt it. The salt causes the snow to assume the liquid form at 
which time it absorbs a certain amount of latent heat; this heat is 
taken from the nearest object, and when that happens to be the feet 
and legs of a horse, the temperature of the parts is reduced so as to 
destroy their vitality. 
