I take one eighth of a pound of walnut-bark and treat with one-eighth of a pound of ammonia--such as spirits of hartshorn--thereby obtaining an extract of walnut with a certain proportion of ammonia. With this I mix one-fourth of a pound of nitrate of silver and one and one-half pound of a mixture of beeswax and cocoa-butter in equal proportions. The whole is thoroughly stirred and heated to sufficient temparature to render the mass homogenous, when it is poured into molds and allowed to cool, the presence of the beeswax causing the compound to become on cooling of the desired consistence. Other fatty substances or pomades may take the place of the cocoa-butter; but I prefer the latter.