the numerous forms of animal and vegetable food a
wonderful similarity of chemical composition prevails.

"Second, he seeks to assuage the cares of his mind, and to banish
uneasy reflections. Fermented liquors are the agents by which this is
effected." [They are variously produced by every people, and the active
principle is in all the same, namely, Alcohol.]

"Third, he desires to multiply his enjoyments, intellectual and animal,
and for the time to exalt them. This he attains by the aid of narcotics.
And of these narcotics, again, it is remarkable that almost every
country or tribe has its own, either aboriginal or imported; so that
the universal instinct of the race has led, somehow or other, to the
universal supply of this want or craving also."

These narcotics are Opium, Hemp, the Betel, Coca, Thorn-Apple, Siberian
Fungus, Hops, Lettuce, Tobacco. The active principles vary in each, thus
differing from foods and stimulants. Our business is now to inquire into
the chemical constituents of tobacco.

The leaves of this plant owe their properties to certain invariable
active principles, which chemistry has enabled us to separate from those
ingredients which are either inert or common to it and other forms of
vegetation. They are two in number,--a volatile alkali, and a volatile
oil, called _nicotin_ and _nicotianin_, respectively. A third powerful
constituent is developed by combustion, which is named the _empyreumatic
oil_.

Starch, gum, albumen, resin, lignin, extractive, and organic acids exist
in tobacco, as they do, in varying proportions, in other plants. But
the herb under consideration contains a relatively larger proportion of
inorganic salts, as those of lime, potassa, and ammonia,--and especially
of highly nitrogenized substances; which explains why tobacco is
so exhausting a crop to the soil, and why ashes are among its best
fertilizers.

The organic base, _nicotin_, (or _nicotia_, as some chemists prefer to
call it,) exists in tobacco combined with an acid in excess, and in this
state is not volatile. As obtained by distillation with caustic soda,
and afterwards treated with sulphuric acid, etc., it is a colorless
fluid, volatilizable, inflammable, of little smell when cold, but of an
exceedingly acrid, burning taste, and alkaline. Nicotia contains a much
larger proportion of nitrogen than most of the other organic alkalies.
In its action on the animal system it is one of the most virulent
poisons k