Physiology, relying on organic chemistry, has at least justified by
experiment the choice of the civilized world. Coffee and tea had been
regarded by the physiologist and the physician as stimulants of the
nervous system, and to a less extent and secondarily of the
circulation, and that was all. To fulfil this object, and to answer the
endless craving for habitual excitants of the cerebral functions, they
had been admitted reluctantly to the diet of their patients, rather as
necessary evils than as positive goods. It was reserved for the
all-searching German mind to discover their better qualities; and it is
only within the last five years, that the self-sacrificing experiments
of Dr. Böcker of Bonn, and of Dr. Julius Lehmann, have raised them to
their proper place in dietetics, as "Accessory Foods." This term, which
we borrow from the remarkable work on "Digestion and its Derangements,"
by Dr. Thomas K. Chambers, of London, is only the slightest of the many
obligations which we hasten to acknowledge ourselves under to this
author, as will appear from citations in the course of this article.

The labors of earlier physiologists and chemists, as Carpenter, Liebig,
and Paget, had resulted in the classification of nutritive substances
under different heads, according to the purposes they served in the
physical economy. Perhaps the most convenient, though not an
unexceptionable division, is into the Saccharine, Oleaginous,
Albuminous, and Gelatinous groups. The first includes those substances
analogous in composition to sugar, being chemically composed of
hydrogen, carbon, and oxygen. Such are starch, gum, cellulose, and so
forth, which are almost identical in their ultimate composition, and
admit of ready conversion into sugar by a simple process of vital
chemistry. The oleaginous group comprises all oily matters, which are
even purer hydro-carbons than the first-mentioned class. The third, or