Atropia, Or Atropine (Gr. one of the Fates), a vegetable alkaloid of highly poisonous properties, extracted from the atropa belladonna, or deadly nightshade. It is obtained from the juice expressed from all parts of the plant, but more particularly from the leaves. It crystallizes in white silky prisms, which have a bitter taste, but no smell. They possess an alkaline reaction, reddening litmus paper; they melt at 194° F., and are volatilized at 284°. Their composition is: carbon, 70.98; oxygen, 16.36; hydrogen, 7.83; and nitrogen, 4.83. Atropia forms crystallizable salts with acids, the sulphate being considerably used in medicine. When in solution it gives a lemon-yellow precipitate with terchloride of gold. It was first obtained by Mein, a German apothecary, by digesting the roots, powdered extremely fine, for several days in alcohol, and afterward separating the other ingredients by various precipitations. From 12 ounces of the root he obtained 20 grains of pure alkali.