How must the food of plants be supplied?

What takes place after it enters the plant?

What name is given to the compounds thus formed?

How are proximates divided?

Which class constitutes the largest part of the plant?

Of what are animals composed, and how do they obtain the materials from
which to form their growth?]

_Oxide of iron_ is iron rust. There are two oxides of iron, the
_peroxide_ (red) and the _protoxide_ (black). The former is a
fertilizer, and the latter poisons plants.

_Oxide of manganese_ is often absent from the ashes of our cultivated
plants.

The food of plants, both organic and inorganic, must be supplied in
certain proportions, and at the time when it is required. In the plant,
this food undergoes such chemical changes as are necessary to growth.

The compounds formed by these chemical combinations are called
_proximates_.

Proximates are of two classes, those not containing nitrogen, and those
which do contain it.

The first class constitute nearly the whole plant.

The second class, although small in quantity, are of the greatest
importance to the farmer, as from them all animal muscle is made.

Animals, like plants, are composed of both organic and inorganic matter,
and their bodies are obtained directly or indirectly from plants.

[What parts of the animal belong to the first class of
proximates?

What to the second?

What is necessary to the perfect development of animals?

Why are seeds valuable for working animals?

What other important use, in animal economy, have proximates of the
first class?

Under what circumstances is animal fat decomposed?]

The first class of proximates in animals comprise the fat, and like
tissues.

The second class form the muscle, hair, gelatine of the bones, etc.

In order that they may be perfectly developed, animals must eat both
classes of proximates, and in the proportions required by their natures.

They require the phosphate of lime and other inorganic food which exist
in plants.

Seeds are the best adapted to the uses of working animals, because they
are rich in all kinds of food required.

Aside from their use in the formation of _fat_, proximates of the first
class are employed in the lungs, as fuel to keep up animal heat, which
is produced (as in fire and decay) by the decomposition of these
substances.

When the food is insufficient for the purposes of heat, the animal's own
fat is decomposed, and carried to th