Animals are composed (like plants) of organic and inorganic matter, and every thing necessary to build them up exists in plants. It seems to be the office of the vegetable world to prepare the gases in the atmosphere, and the minerals in the earth for the uses of animal life, and to effect this plants put these gases and minerals together in the form of the various proximates (or compound substances) which we have just described.
In animals the compounds containing no nitrogen comprise the fatty substances, parts of the blood, etc., while the protein compound, or those which do contain nitrogen, form the muscle, a part of the bones, the hair, and other portions of the animal.
Animals contain a larger proportion of inorganic matter than plants do. Bones contain a large quantity of phosphate of lime, and we find other inorganic materials performing important offices in the system.
In order that animals may be perfectly developed, they must of course receive as food all of the materials required to form their bodies. They cannot live if fed entirely on one ingredient. Thus, if starch alone be eaten by the animal, he might become fat, but his strength would soon fail, because his food contains nothing to keep up the vigor of his muscles. If on the contrary the food of an animal consisted entirely of gluten, he might be very strong from a superior development of muscle, but would not be fat. Hence we see that in order to keep up the proper proportion of both fat and muscle in our animals (or in ourselves), the food must be such as contains a proper proportion of the two kinds of proximates.
Why is grain good for food?
On what does the value of flour depend?
Is there any relation between the ashy part of plants and those of animals?
How may we account for unhealthy bones and teeth?
It is for this reason that grain, such as wheat for instance, is so good for food. It contains both classes of proximates, and furnishes material for the formation of both fat and muscle. The value of flour depends very much on the manner in which it is manufactured. This will be soon explained.
What is a probable cause of consumption?