organic life, are always the dearest articles of consumption. Certainly
it is not as positive nutriment that we recommend the use of coffee and
tea; for although they contain a relatively large amount of nitrogen,
that supply can be better taken in solid food. Their benefit is
two-fold. While they save more than enough of the waste of tissue to
justify their use as economical beverages, they supply a need of the
nervous system of no small importance. They cheer, refresh, and
console. They thus fill a place in the wants of humanity which common
articles of food cannot, inasmuch as they satisfy the cravings of the
spirit as well as of the flesh.

We have before attempted to show that the human race is liable to a
peculiar and constant waste from the development of the nervous system,
and that the body has to answer for the labor of the mind. At first
thought, we shall find it difficult to appreciate the endless vigilance
and activity of the brain. Like the other organisms which possess a
proper nervous system, man carries on the common organic processes of
life with a regularity and unfailing accuracy which seem to verge on
the mechanical forces, or to be, at least, automatic. All habitual
voluntary acts by repetition become almost automatic, or require no
perceptibly distinct impulse of the will. When we emerge from this
necessary field of labor, we come to those functions peculiar to the
proper brain. Here all is continual action. Thought, imagination, will,
the conflicting passions, language, and even articulation, claim their
first impulse from the nervous centre. The idlest reverie, as well as
the most profound study, taxes the brain. That distinguishing attribute
of man can almost never rest. In sleep, to be sure, we find a seeming
exception. Then only its inferior portion remains necessarily at work
to supervise the breathing function. Yet we know that we have often
dreamed,--while we do not know how often we fail to recall our dreams.