"Mucilage, albumen, or gluten, extractive, a bitter principle, an essential oil, nitrate of potass, which occasions its deflagration, muriate of potass, and a peculiar proximate principle, upon which the virtues of the plant are supposed to depend, and which has therefore been named _Nicotin_. This peculiar principle is considered by some, as approaching the essential oil in its properties. It is colorless, has an acrid taste, and the peculiar smell of tobacco; and occasions violent sneezing. With alcohol and water it forms a colorless solution, from which it is precipitated by a tincture of galls. Tobacco yields its active matter to water and proof spirit, but most perfectly to the latter; long boiling weakens its powers. A most powerful oil may be obtained by distillation, and separating it from the surface of the water on which it floats." IV. MEDICAL PROPERTIES. These are considered to be those of a powerful _narcotic_, _antispasmodic_, _emetic_, _cathartic_, _sudorific_, and _diuretic_. "As a _narcotic_, it is endued with the most energetic, poisonous properties, producing, when administered even in small doses, severe nausea and vomiting, cold sweats, universal tremors, with extreme muscular debility." From its exerting a peculiar action on the nervous system, as ascertained by the well directed experiments of Mr. Brodie, it powerfully controls the action of the heart and arteries, producing invariably a weak, tremulous pulse, with all the apparent symptoms of approaching death. And so different is its operation from that of other narcotics, that it actually operates with more destructive efficacy, when used by way of injection, than when applied either to the skin, or when taken into the stomach. From what has been said of its narcotic powers, you, Gentlemen, will readily infer its virtue as an article of _medicine_. If we wish, at any time, to prostrate the powers of life in the most sudden and awful manner, we have but to administer a dose of tobacco, and our object is accomplished. Hence its use in obstinate constipation, in cholic, in the iliac passion, and in stranguary. As it is conceded that its efficacy as an _antispasmodic_ depends upon its power to prostrate every vestige of tone and elasticity in the muscular fibre, prudence would dictate that it should be used with the utmost circumspection, when the system had been previously exhausted by the disease, or by the antecedent method of cure. Melancholy instances are on record, of the fatal effects of this medicine when administered without this caution, both as an internal remedy, and as an external application in cutaneous diseases. Two instances will suffice.