Dictionary.net

Isinglass composition on silk to protect wound.

Sticking plaster made of silk, orig. applied as patches on the face by ladies at court.

Isinglass plaster of the U. S. Ph., 1890.

A plaster consisting of a solution of isinglass in water spread thinly and very smoothly upon a silk backing so as to adhere to the skin when moistened, the silk being painted on the reverse side with tincture of benzoin.