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?