Page:Popular Science Monthly Volume 25.djvu/228

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218
THE POPULAR SCIENCE MONTHLY.

trembling; may grow rhubarb and make pies and puddings in defiance of the agent. When this is the case, his craving for potato-potash will probably diminish, and his children may actually feed on bread.

As regards the nutritive value of the potato, it is well to understand that the common notion concerning its cheapness as an article of food is a fallacy. Taking Dr. Edward Smith's figures, 760 grains of carbon and 24 grains of nitrogen are contained in one pound of potatoes; two and one half pounds of potatoes are required to supply the amount of carbon contained in one pound of bread; and three and one half pounds of potatoes are necessary for supplying the nitrogen of one pound of bread. With bread at three halfpence per pound, potatoes should cost less than one halfpenny per pound, in order to be as cheap as bread for the hard-working man who requires an abundance of nitrogenous food.

My own observations in Ireland have fully convinced me of the wisdom of William Cobbett's denunciation of the potato as a staple article of food. The bulk that has to be eaten, and is eaten, in order to sustain life, converts the potato-feeder into a mere assimilating machine during a large part of the day, and renders him unfit for any kind of vigorous mental or bodily exertion. If I were the autocratic Czar of Ireland, my first step toward the regeneration of the Irish people would be the introduction, acclimatizing, and dissemination of the Colorado beetle, in order to produce a complete and permanent potato-famine. The effect of potato-feeding may be studied by watching the work of a potato-fed Irish mower or reaper who comes across to work upon an English farm where the harvest-men are fed in the farm-house and where beer is not excessive. The improvement of his working powers after two or three weeks of English feeding is comparable to that of a horse when fed upon corn, beans, and hay, after feeding for a year on grass only.

The reader may have observed that the starch-foods already described are all derived from the roots or stems of plants. Many others might be named that are used in tropical climates where little labor is demanded or done, and but little nitrogenous food required. Having treated the cookery of the chief constituents of these parts of the plant, the fiber and the starch, I now come to food obtained from the seeds and the leaves.

Taking the seeds first, as the more important, it becomes necessary to describe the nitrogenous constituents which are more abundant in them than in any other part of the plant, though they also contain the starch and cell material, or woody fiber, as already stated.

In No. 29 of this series, page 65, I described a method of separating starch from flour by washing a piece of dough in water, and thereby removing the starch-granules, which fall to the bottom of the water. If this washing is continued until no further milkiness of the water is produced, the piece of dough will be much reduced in dimen-