Note 86 — NATURAL HISTORY OF CAGE BIRDS. (continued 6)

To prepare this tincture, take of water four parts, of black oxide of iron one part; boil the oxide with the water, and then pass a current of chlorine gas through the mixture till it will absorb no more; filter the liquor and evaporate over a slow fire to the consistence of an extract; when this is cold, pour upon it of hydrochloric ether three parts; let it macerate without heat for several days; then add of alcoholised hydrochloric acid nine parts; macerate again, filter the liquor, and expose it to the sun.—Translator.