Tabacum. Virginian Tobacco. Nat. Ord. Solanaceae. Linn. Syst. Pentandria Mono-gynia. Hab. Tropical America; now cultivated in most parts of the world.

Med. Prop. and Action. The dried leaves (off.) are sedative and antispasmodic; also purgative, emetic, and diuretic in a minor degree. When locally applied, it appears to be stimulant; thus, when it is used in the form of snuff, it causes violent sneezing, and, when chewed, greatly increases the flow of saliva. When taken in small doses, by those unaccustomed to its use, it causes nausea, vomiting, vertigo, and a great depression of the vital powers: in larger doses, these symptoms increase in intensity; there is great prostration; a low, weak, trembling pulse; cold, clammy perspiration, obscurity of vision, and a tendency to faint. In extreme cases, convulsions, paralysis, and coma precede death. These symptoms evidence themselves whether Tobacco has been taken by mouth, or in the form of enema, or even in some cases when the leaves have been applied to a large abraded surface. In its operation and effects it is closely allied to Digitalis. Its activity depends upon a liquid alkaloid, Nicotina (C20H14N2), and upon a concrete volatile oil, Nicotianin. Nicotina is an energetic poison, almost equalling Hydrocyanic Acid in potency. Nicotianin also possesses poisonous properties. According to the experiments of Sir B. Brodie, an aqueous infusion of Tobacco causes paralysis of the heart, through the medium of the nerves; whilst the empy-reumatic oil of Tobacco was not found to produce this effect: thus, one drop of the oil applied to the tongue of a cat caused convulsions and death in two minutes; and on opening the body immediately afterwards, the heart's action was unaffected. Tobacco is a remedy which should be used with great caution, as it causes such perfect prostration that the vital powers have not sufficient strength left to recover themselves, and a fatal termination follows. Fatal results from Tobacco enemas are recorded by Sir A. Cooper, Sir C. Bell, Dr. Copland, and others. Gr. xxx. of the leaves in infusion is the smallest quantity which has proved fatal. Chloroform inhalation has almost entirely superseded the use of Tobacco enemata in cases of Strangulated Hernia. Smoking Tobacco and Snuff-taking, when first commenced, cause nausea, vomiting, &c. Their moderate use does not appear to be injurious, but excessive indulgence in them induces dyspepsia and a cachectic state of the body. Contrary to the opinion of some writers, I am inclined to believe, from many circumstances, that smoking Tobacco is, to a certain extent, a preventive of fever arising from malaria in tropical countries.

Offuc. Prep. Enema Tabaci (Leaf Tobacco grs. xx.; Boiling Water fl. oz. viij. Infuse for half-an-hour, and strain).

Dose. Tobacco is not a remedy fitted for internal administration, on account of the great depression it produces: gr. xv. - xx. in infusion is the quantity which it is safe to administer as an enema.