Gentlemen--there is a baneful habit, diffused, like the atmosphere, through all classes, and affecting all the ramifications of society. And this habit owes much of its prevalence to the advice and example of respectable physicians. We indulge the hope, from the great increase of medical knowledge, that the time will soon arrive, when persons disposed to vicious indulgence will be unable to entrench themselves behind our professional advice. I am aware that I tread on dangerous ground, in attempting to investigate the propriety of a practice which has been introduced and approved by a large portion of the members of this respectable Society. You may start at the suggestion, and regard it as unworthy of your notice. Let me hope, however, that you will suspend your opinions, while I endeavor to present the _natural history, chemical composition_, and _medical properties_ of one of our most deadly narcotics--the _Tabaci Folia_, _Nicotiana Tabacum_, i. e. tobacco. If in the prosecution of this inquiry, we shall be able to discover the great and injurious effects which the use of this poisonous plant produces on the constitution, I shall be excused, if I urge this subject on your consideration with more than ordinary importunity. I. NATURAL HISTORY. "This plant was unknown in Europe until after the discovery of America by the Spaniards, and was first carried to England by Sir Francis Drake, A. D. 1560. The natives of this continent call it _petun_; those of the islands, _yoli_. The Spaniards, who gave it the name of _tobacco_, took that name from Tabaco, a province in Yucatan, where they first found it, and first learned its use. Some contend that it derives its name from Tobago, one of the Caribbee Islands, discovered by Columbus, in 1498."[A] It received the name _tobacco_ from Hernandez de Toledo, who first sent it to Spain and Portugal. The botanic description of this plant may be found in most works on the science of botany: and therefore I shall not detain you with it at this time. The plant, while growing exhibits a very beautiful appearance, but is so extremely nauseous, that in all the variety of insects, only one is found to feed upon it. This is a worm "_sui generis_," the mode of its propagation being entirely unknown; and from its being the only living creature (man excepted) that will devour this plant,[B] it is called "_tobacco worm_." [Footnote A: See Rees' Cyclopedia.] [Footnote B: Dictionary of Arts and Sciences.] II. SENSIBLE QUALITIES. It is of a yellowish green color; it has a strong, narcotic, and foetid odor, with a bitter and extremely acrid taste. III. CHEMICAL COMPOSITION.