Page:Popular Science Monthly Volume 51.djvu/671

Rh animal. Bowditch has shown in his studies upon the growth of children that native-born Americans are larger and better developed than those of foreign parentage, and ascribes the reason to the better conditions which surround the American children. So children from the non-laboring classes are larger than those from laboring homes.

While these data show only the dependence of physical development upon nutrition, still we are not without similar evidence showing that mental development depends also upon the character and amount of a people's food. The causes for the intellectual and temperamental differences between the races of different countries may be ascribed, at least in part, to the character of their dietaries. Contrast the Chinese and English, for instance: the former are mentally and emotionally very different from and inferior to the latter, as might be expected from the quality of their food. The difference between these two races is typical of the difference between types of children to be seen frequently in home and school. The one is slow and obtuse intellectually, and possessed of an indifferent or negative emotional and moral nature; while the other is keen and vigorous in thought, and positive in emotions and morals; and one who strives by concrete observation to account for these differences can not fail to see plainly ofttimes that they are due to the quality and quantity of food which the children eat.

It is important to note that cerebral nerve cells demand particular materials for their proper nutrition. Food which will make bone will not be best suited to the nourishment of an active brain, and vice versa. So fat-producing foods, while of course of value in one's diet, yet do not furnish in large measure nutrients for the repletion of nerve cells. Prof. Ladd says that the chemistry of the nerve cells is in the main protoplasmic, and therefore rich in albuminous bodies. And again, "Of the solids composing the nervous substance, more than one half in the gray and one fourth in the white consist of proteid or albuminous bodies." The foods that are best calculated to nourish the brain, then, are those containing a large amount of protein or albumin, rather than fats, carbohydrates, or minerals, the three other important constituents of foods. But in many homes, as well in those of the rich as of the poor, the children's dietaries contain comparatively little albuminous food, as may be seen from the following analysis of the nutritive values of the various common articles of a child's diet: Beef contains 29·7 per cent of protein; chicken, 19·3 per