Mustard plasters or poultices have been already spoken of under the heading of poultices. Plasters or charges are either simple or medicated. The former are used to afford support to an injured or weakened part.



The latter, besides performing this service, are intended to effect the removal of enlargements, especially in connection with the legs.

Chamois-leather adapted to the leg, and neatly sewn on with stitches known to ladies as "herring-bones", are often called plasters in racing stables, but they do not properly belong to that order of applications.

The medical plasters employed in veterinary practice have a base of pitch, resin, wax, or a mixture of these substances, with which the drugs to be used are incorporated by first melting the former and stirring in the latter until the whole is cool enough to be applied to the skin. Instead of being spread on leather, as is often done in human practice, they are directly applied to the part by means of a spatula or knife, and then tow is cut into lengths of about half an inch and stuck on to the plaster while warm. They may be employed upon any part of the body, but their use is for the most part confined to the limbs, where they are used for the purpose of giving support to sprained and weakened tendons, joints, and ligaments, or to fractured bones.