Blistering is an operation frequently resorted to in the treatment of horses, and many permanent blemishes result from the use of improper materials and the neglect of simple after-precautions. As a preliminary measure the hair on the part to be blistered should be first closely clipped and the scurf brushed out of the skin.
If a front limb is to be treated, the animal should be turned round in the stall and secured to both pillar-reins in such a manner that he cannot bring his muzzle into contact with an uplifted leg.
When a hind limb is to be blistered, the animal should be racked up short. Even in this position some irritable horses will injure themselves in front when suffering pain behind, and it may be necessary to keep such a one under observation for a few hours after the application is made. If only one limb is operated upon, its fellow may be enveloped in a soft bandage for the protection of both, for the patient is sometimes disposed to rub the suffering member against the other leg.
Only sufficient bedding should be used to prevent the patient from slipping down, long loose straw causing unnecessary annoyance when brought into contact with the blistered surface. Damp used straw is to be preferred to moss litter or saw-dust, which gets upon the blistered surface and is very objectionable.
Horses disposed to "filling" of the legs, and mares "in season", are specially susceptible to the action of vesicants, and these should be modified in strength if other reasons prevent the postponement of the application. An unnerved horse should on no account be blistered. The hollow of the heel should in no case receive any portion of the blister, and the space should be filled up with lard previous to the application being made.
About ten minutes of hand rubbing is usually sufficient to produce the desired effect, and the morning should be chosen for this operation, as affording opportunities to watch the patient and keep him out of trouble, besides which, the more acute stage will be past before leaving him for the night.
If the application has proved effectual, there will be vesicles or bladders upon the part next day, with some swelling of the limb though abatement of the pain. On the third day it is usual to bathe with warm water and soap, and when dry apply some emollient ointment or sweet-oil.
It may be doubted whether this is a desirable course to pursue. Better results, we think, would be obtained by allowing a hardened scale to form and remain, but humane considerations make most of us desire to relieve the suffering beast as soon as possible and give him the opportunity to lie down.
To prevent the patient from gnawing the member when released, an apparatus known as a "cradle" (fig. 452) is put on his neck in such a manner as to give him the maximum amount of liberty without the power to injure himself. If a horse is turned out to grass with a cradle on, the pieces of wood of which the cradle is composed should be held together with nothing stronger than "fillis", as fatal accidents have occurred through an animal getting a hind foot caught up when trying to scratch the parts covered, a risk which is increased if the shoes have not previously been removed.