e to act, err in the second manner. Led away by
the brilliant hues and wonderful transformations of the laboratory,
they forget the size of the world outside, in which these changes are
enacted, and the quiet way in which Nature works. The breath of chlorine
is deadly, but we daily eat it in safety, wrapped in its poison-proof
envelope of sodium, as common salt. Carbonic acid is among the gases
most hostile to man, but he drinks it in soda-water or Champagne with
impunity. So we cannot explain how a poison will act, if introduced
into the body in the diluted form in which Nature offers it, and there
subjected to the complicated chemico-vital processes which constitute
life.

In the alembic of the chemist we may learn analysis, and from it infer,
but not imitate, save in a few instances, the synthesis of Nature.
Changes in the arrangement of atoms, without one particle altered that
we can discover, may make all the difference between starch and sugar.
By an obscure change, which we call fermentation, these may become
alcohol, the great stimulant of the world. By subtracting one atom of
water from its elements we change this to ether, the new-found _lethe_
of pain. As from the inexhaustible bottle of the magician, the chemist
can furnish us from the same two elements air or aquafortis. We may be
pardoned these familiar examples to prove that we must not judge of
things by their palpable qualities, when concentrated or in the gross.
That fiery demon, nitric acid, is hid, harmless in its imperceptible
subdivision, in the dew on every flower.

From all this we conclude that the evil effects of tobacco are to be
determined by their proved _physiological_ effects; and also that we
must aid our decision by a survey of its general asserted effects. In
treating of these effects, we shall speak, first, of what is known;
second, of what its opponents assert; and, third, of what we claim as
the results of its use.

What is absolutely known is very little. We see occasional instances of
declining health; we learn that the sufferers smoke or chew, and we are
very apt to ascribe all their maladies to tobacco. So far as we are
aware, the most notorious organic lesion which has been supposed due to
this practice is a peculiar form of cancer of the lip, where the pipe,
and particularly the clay pipe, has pressed upon the part. But more
ample statistics have disproved this theory.

We have as yet become acquainted with no satisfactory