The Chemistry of Food and Nutrition | Page 2

booklets on food of a very practical character, at from a penny
to threepence each.
Popular literature abounds in unsound statements on food. It is
unfortunate that many ardent workers in the cause of health are lacking
in scientific knowledge, especially of physiology and chemistry. By
their immature and sweeping statements from the platform and press,
they often bring discredit on a good cause. Matters of health must be
primarily based on experience and we must bear in mind that each

person can at the most have full knowledge of himself alone, and to a
less degree of his family and intimates. The general rules of health are
applicable to all alike, but not in their details. Owing to individual
imperfections of constitution, difference of temperament and
environment, there is danger when one man attempts to measure others
by his own standard.
For the opinions here expressed I only must be held responsible, and
not the Society publishing the pamphlet.
Vegetarians, generally, place the humane as the highest reason for their
practice, though the determining cause of the change from a flesh diet
has been in most cases bad health.
A vegetarian may be defined as one who abstains from all animals as
food. The term animal is used in its proper scientific sense (comprising
insects, molluscs, crustaceans, fish, etc.). Animal products are not
excluded, though they are not considered really necessary. They are
looked upon as a great convenience, whilst free from nearly all the
objections appertaining to flesh food.
A.W.D.

The Chemistry of Food and Nutrition
By A.W. DUNCAN, F.C.S.
We may define a food to be any substance which will repair the
functional waste of the body, increase its growth, or maintain the heat,
muscular, and nervous energy. In its most comprehensive sense, the
oxygen of the air is a food; as although it is admitted by the lungs, it
passes into the blood, and there re-acts upon the other food which has
passed through the stomach. It is usual, however, to restrict the term
food to such nutriment as enters the body by the intestinal canal. Water
is often spoken of as being distinct from food, but for this there is no
sufficient reason.
Many popular writers have divided foods into flesh-formers,
heat-givers, and bone-formers. Although attractive from its simplicity,
this classification will not bear criticism. Flesh-formers are also
heat-givers. Only a portion of the mineral matter goes to form bone.
Class I.--INORGANIC COMPOUNDS. Sub-class 1. Water. 2. Mineral
Matter or Salts. Class II--ORGANIC COMPOUNDS. 1.
Non-Nitrogeneous or Ternary Compounds. a Carbohydrates. b Oils. c

Organic Acids. 2. Nitrogenous Compounds. a Proteids. b Osseids.
Class III.--NON-NUTRITIVES, FOOD ADJUNCTS AND DRUGS.
Essential Oils, Alkaloids, Extractives, Alcohol, &c.
These last are not strictly foods, if we keep to the definition already
given; but they are consumed with the true foods or nutrients,
comprised in the other two classes, and cannot well be excluded from
consideration.
Water forms an essential part of all the tissues of the body. It is the
solvent and carrier of other substances.
Mineral Matter or Salts, is left as an ash when food is thoroughly burnt.
The most important salts are calcium phosphate, carbonate and fluoride,
sodium chloride, potassium phosphate and chloride, and compounds of
magnesium, iron and silicon.
Mineral matter is quite as necessary for plant as for animal life, and is
therefore present in all food, except in the case of some highly-prepared
ones, such as sugar, starch and oil. Children require a good proportion
of calcium phosphate for the growth of their bones, whilst adults
require less. The outer part of the grain of cereals is the richest in
mineral constituents, white flour and rice are deficient. Wheatmeal and
oatmeal are especially recommended for the quantity of phosphates and
other salts contained in them. Mineral matter is necessary not only for
the bones but for every tissue of the body.
When haricots are cooked, the liquid is often thrown away, and the
beans served nearly dry, or with parsley or other sauce. Not only is the
food less tasty but important saline constituents are lost. The author has
made the following experiments:--German whole lentils, Egyptian split
red lentils and medium haricot beans were soaked all night (16 hours)
in just sufficient cold water to keep them covered. The water was
poured off and evaporated, the residue heated in the steam-oven to
perfect dryness and weighed. After pouring off the water, the haricots
were boiled in more water until thoroughly cooked, the liquid being
kept as low as possible. The liquid was poured off as clear as possible,
from the haricots, evaporated and dried. The ash was taken in each case,
and the alkalinity of the water-soluble ash was calculated as potash
(K_{2}O). The quantity of water which could be poured off was