The white potato is a native of Chile, and was introduced into Europe by the Spaniards about 1580. It came into this country about the end of the sixteenth century. The skin of the potato constitutes 2 1/2 per cent. of the whole; the cortical layer 8.5 per cent. The remainder is the flesh. The edible portion is 78.3 per cent. water, 2.2 per cent. proteids, 0.1 per cent. fat, 18.4 per cent. carbohydrates, chiefly starch, and 1 per cent. ash. The fuel value of the potato is 385 calories per pound. A potato diet is one-sided. Four and one-half pounds of raw potatoes equal in food value about one pound of dry, uncooked rice. The juice of the potato contains citric acid, with some succinic and tartaric acids. The mineral matter is largely potash salts. Much starch is made from the potato.

Potatoes are cooked chiefly by boiling, baking, and frying. Heat expands the water in the potato and ruptures the starch cells. Baking best breaks up the starch granules and is the best way to cook the potato. Potatoes boiled with the skins on lose less nutriment than when otherwise boiled. Fried potato chips contain much fat, and thus are more indigestible than boiled or baked potatoes, and are more fattening.

Potatoes fertilized in growing by muriate of potash are usually watery and more or less insipid. Sulphate of potash is better with which to fertilize potatoes in growing. If potatoes are allowed to freeze, some of the starch is converted into sugar and the potatoes have a sweet, unnatural taste. The flavor of potatoes varies as to variety and as to methods of growing them and in the soil in which they are grown.

Potatoes may disagree with some who have more or less inability to digest starch, but, as a rule, they are useful and wholesome when properly cooked and eaten in proper quantity. There are many persons with whom potatoes do not agree and they must therefore avoid them. To individuals with peculiar idiosyncrasies they may be actually poisonous. In such cases the offending principle appears to be what is called solanin in the potato. Sprouted potatoes contain more solanin than fresh potatoes, and sprouted potatoes should, as a rule, not be eaten. Potatoes kept too long, say one year, should not be eaten. There is little or no solanin in fresh potatoes. If you wish less nitrogen in your potatoes, boil after they have been peeled; if more nitrogen and a stronger food, boil with the skins on.

I look upon white potatoes as among the most innocent of the starchy foods, with a tendency to increase the alkalinity of the blood. One thing remember, if you wish to cut down your fat, - keep clear of fried potato chips as they are usually cooked.

Sweet potatoes, in this country, fill a large place in the general diet. They are strong food and much more fattening than the white potatoes. They contain proteids, 3.6; fat, 1.3; carbohydrates 49.1, and ash, 2. They are more difficult of digestion than white potatoes, and only the strong and vigorous can eat them with impunity. They are best boiled with the skins on. Fried, they are very rich, with too much fats for the average stomach. Yams are much like them.