the maintenance of health and strength, may be property classed as
foods, whether they be obtained from the animal, vegetable, or mineral
kingdoms; thus the iron, sulphur, phosphorus, lime, potash, etc.,
required by the system usually exist in and are organically combined
with the various foods in common use, and they are perhaps quite as
essential to the physical well-being as albuminoid, fatty, and
saccharine matters. When the system is suffering from lack of any of
the above mentioned chemicals, their administration is to be regarded
as the giving of nutritive substances, although they be prescribed by
a physician in divided doses and procured from a pharmacist.

On the other hand, a medicine is any substance that does not naturally
enter into the composition of the body, but which has the power, when
skillfully used, to modify the physical processes so that
physiological disorder--disease, shall be replaced by physiological
harmony--health. Belladonna, hyoscyamus, opium, etc., are familiar
examples of medicaments. Therefore a food is any substance that is
capable of directly contributing to the nutrition of the body, and
medicine is a substance competent, under proper conditions, to secure
the same results indirectly. Viewed in the light of the above
definition, cod-liver oil is to be regarded as a very valuable food,
as well as a most effective remedy both for the prevention and cure of
consumption.

I have previously stated that food is divided by physiologists into
three great classes. The albuminoids are used to build up the
organism, while the fatty and saccharine are burned in the body to
keep it warm. Although these are the chief functions devolving on the
above mentioned food elements, yet they are mutually interdependent on
each other for the proper performance of their several offices. Thus