Seak isinglass in water - till it is soft, then dissolve it in the smallest possible quantity of proof spirit, by the aid of a gentle heat; in two ounces of this mixture dissolve ten grains of ammoniaeum, and whilst still liquid, add half a drachm of mastic dissolved in three drachms of rectified spirit; stir well together, and put into small bottles for sale. {See 139.)

Directions for use. - Liquify the cement by standing the bottle in hot water, and use it directly. The cement improves the oftener the bottle is thus warmed, and resists the action of water and moisture perfectly.