Although Tobacco has been only comparatively recently introduced amongst the inhabitants of the Old World, it is more extensively employed than any other narcotic. It is the produce of various species of the genus _Nicotiana_. The practice of smoking the leaves of these plants was introduced from the New World. The species, which is a native of America, and which supplies the greater proportion of the Tobacco smoked in Europe, is the _Nicotiana Tabacum_. The leaves of these plants contain an active and highly poisonous principle called _Nicotine_, which is the agent that produces the narcotic effect experienced in smoking. This narcotic effect resembles in some measure that of alcohol. Tobacco has, however, a less stimulant effect than alcohol, and produces, especially at first, a greater derangement of the general nervous system. The chemical analysis of one pound of Tobacco is exhibited in Case 98. Cases 93 to 97 contain a series of specimens of the leaves of species and varieties of Tobacco cultivated in various parts of the world, with samples also of the Cigars and Tobaccos manufactured from them. Examples of varieties of Snuffs used in this and other countries will be seen in Case 97. Snuffs are usually made from the stalks and ribs of tobacco leaves. Tobacco is liable to be adulterated with the leaves of other plants; these, however, can be detected under the microscope. Specimens of Tobacco adulterated with other leaves are illustrated in the diagram near the cases. Opium is used extensively as a medicine, on account of its power of alleviating pain and inducing sleep. It is a very powerful, and consequently dangerous narcotic poison, and should never be taken except under medical advice. In small doses it acts as a stimulant. On account of this latter property and its subsequent soothing influence, it has been indulged in by man, and is consumed largely in China and other parts of the world as a dietetical luxury. When taken for this purpose it is smoked, and is generally consumed with tobacco or some other leaf in a pipe. Pipes used for this purpose in China are exhibited in the cases containing Chinese food, with a collection of Chinese tobaccos, most of which appear to contain Opium. The practice of “opium eating,” as it is called, exerts a most prejudicial effect upon the system; and although not rapidly destroying life, the victim of this habit is after a time rendered perfectly miserable if not able to procure this indulgence. As is the case with alcohol and tobacco, the system becomes accustomed to the use of this narcotic, and prodigious quantities have been consumed by those who have addicted themselves to the practice of taking it for the sake of its effect on the system.