erest to the
stock-feeder:--

Weight necessary to sustain a
man's life for twenty-four hours.

Kinds of Food. Ounces.

Potatoes 13.4
Apples 20.7
Oatmeal 3.4
Flour 3.5
Pea Meal 3.5
Bread 6.4
Milk 21.2
Carrots 25.6
Cabbage 31.8
Butter 1.8
Lump Sugar 3.9

These figures show the relative calefacient, or heat-producing powers of
the different foods named _outside_ the body; but there is some doubt as
to their having the same relative values when burned _within_ the body.
The woody fibre of the carrots and cabbages is very combustible in the
coal furnace, but it is very doubtful if more than 20 or 30 per cent. of
this substance is ever burned in the _animal furnace_. However, such
inquiries as those carried out by Frankland possess great value; and
tables constructed upon their results cannot fail to be useful in the
drawing up of dietary scales, whether for man or for the inferior
animals.

I may here remark, that in my opinion the nutritive value of food admits
of being very accurately determined by the adoption of the following
method:--

1. The animal experimented upon to be supplied daily with a weighed
quantity of food, the composition and calefacient value of which had
been accurately determined. 2. The gases, vapors, and liquid and solid
egesta thrown off from its body to be collected, analysed, and the
calefacient[15] value of the combustible portion of them to be determined.
3. The increase (if any) of the weight of the animal to be ascertained.
4. The difference between the amount of heat evolvable by the foods
before being consumed, and that actually obtained by the combustion
of the egesta into which they were ultimately converted, would be the
amount actually set free and rendered available within the body. The
calculations would be somewhat affected by an increase in the weight
of the animal's body; but it would not be difficult to keep the weight
stationary, or nearly so, and there are other ways of getting over
such a difficulty. An experiment such as this would be a costly one,
and could not be properly conducted unless by the aid of an apparatus
simila