III. Chemical Composition.
"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."