Where is the original homoeopathic pathogenesis of Tabacum ? In Hartlaub and Trink's Materia Medica , Vol. III. What preparation of Tobacco do we use ? A tincture from the dried leaves of the genuine Havana Tobacco . How is it prepared ? The dried leaves are cut up and covered with five parts, by weight, of alcohol, placed in well stoppered bottle in a dark, cool place for eight days, being shaken twice a day. Decant, strain and filter. Drug power, 1/10. The tincture is clear brown of penetrating odor. What is the alkaloid of Tobacco ? Nicotine . What is the general action of this drug ? Acts especially on the medulla and pneumo-gastric nerve, producing relaxation and paralysis of the involuntary muscular system. Precordial oppression, nausea, vertigo, death-like pallor, icy coldness and sweat, nervous tremor and debility are some of the results of its action. What are a few of its chief characteristics ?