The grain of wheat consists of two parts, with which the miller is familiar—the inner grain and the skin that covers it. The inner grain gives the pure wheat flour; the skin, when separated, forms the bran. The miller cannot entirely peel off the skin from his grain, and thus some of it is unavoidably ground up with his flour. By sifting, he separates it more or less completely: his seconds, middlings, &c., owing their colour to the proportion of brown bran that has passed through the sieve along with the flour. The whole meal, as it is called, of which the so-named brown household bread is made, consists of the entire grain ground up together—used as it comes from the mill-stones unsifted, and therefore containing all the bran.
The first white flour, therefore, may be said to contain no bran, while the whole meal contains all that grew naturally upon the grain.
What is the composition of these two portions of the seed? How much do they respectively contain of the several constituents of the animal body? How much of each is contained also in the whole grain?
1. The fat. Of this ingredient a thousand pounds of the
| Whole grain | contain | 28 | lbs. |
| Fine Flour, | " | 20 | " |
| Bran, | " | 60 | " |
So that the bran is much richer in fat than the interior part of the grain, and the whole grain ground together (whole meal) richer than the finer part of the flour in the proportion of nearly one half.
2. The muscular matter. I have had no opportunity as yet of ascertaining the relative proportions of this ingredient in the bran and fine flour of the same sample of grain. Numerous experiments, however, have been made in my laboratory, to determine these proportions in the fine flour and whole seed of several varieties of grain. The general result of these is, that the whole grain uniformly contains a larger quantity, weight for weight, than the fine flour extracted from it does. The particular results in the case of wheat and Indian corn were as follows:—A thousand pounds of the whole grain and of the fine flour contained of muscular matter respectively,—
| Whole grain. | Fine Flour. | |
| Wheat, | 156 lbs. | 130 lbs. |
| Indian Corn, | 140 | 110 |
Of the material out of which the animal muscle is to be formed, the whole meal or grain of wheat contains one-fifth more than the finest flour does. For maintaining muscular strength, therefore, it must be more valuable in an equal proportion.
3. Bone material and Saline matter.—Of these mineral constituents, as they may be called, of the animal body, a thousand pounds of bran, whole meal and fine flour, contain respectively,—