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The external appearance of atropium. Varies considerably according to the different methods by which it is obtained. When precipitated from the decoction of the herb by a solution of potash, it appears in the form of very small short crystals, constituting a sandy powder. When thrown down by ammonia from an aqueous solution of its salts, it appears in flakes like wax, if the solution is much diluted ; if concentrated, it is gelatinous likeprecipitated alumina; when obtained by cooling of a hot solution in alcohol, it crystahizes in long, acicular, transparent, brilliant crystals, often exceeding one inch in length, which are sometimes feathery ; at other times starhke in appearance, and sometimes they are single crystals. Atropium, however, is only obtained in such a crystalline state when rendered perfectly pure by repeated solution in muriatic acid, and precipitation by ammonia : a solution of impure atropium which I made by boiling the decoction of the leaves of atropa belladonna with magnesia, and dissolving the precipi- tated alkali in hot alcohol, has not, during half a year, deposited any crystals but merely flakes. prev next |