The pea is quite as highly valued for table use as the bean, and, perhaps, is almost as extensively cultivated. The pea, however, is not usually eaten in the pod. It is probably indigenous to Central Europe, but has been so long cultivated that an exact history of its original distribution is not known. There are many different varieties of the pea, but the one most highly prized is a small and very sweet pea. The larger variety does not have the palatability and other highly prized edible qualities that distinguish the smaller variety. The pea is found in the markets of the United States throughout the whole year, being grown under cover in the winter time. It becomes an abundant crop from early in the spring until very late in the autumn. Immense quantities of peas are preserved by canning, and in this condition they retain their edible properties almost without impairment throughout the entire winter. The pea is valued as a food in many forms.
Composition.—
| Water. | Ash. | Protein. | Fiber. | Starch, Sugar, etc. | Fat. | |
|---|---|---|---|---|---|---|
| Percent. | Percent. | Percent. | Percent. | Percent. | Percent. | |
| Green pea, | 79.93 | .78 | 3.87 | 1.63 | 13.30 | .49 |
| Dry pea, | 12.62 | 3.11 | 27.04 | 3.90 | 51.75 | 1.58 |
The above data show that the pea is a markedly nitrogenous food, especially the dry pea. Even in the green pea nearly four percent of its weight is protein.
A comparison of the composition of the pea with that of the bean shows that the pea is even more nitrogenous in character than the bean.
Potatoes.
—One of the most important vegetables as well as food products in general is that class of products to which the term potato is given. The term strictly should apply only to that class known as white or Irish potato (Solanum tuberosum L.). The potato, as indicated by the name, belongs to a family of plants which is considered poisonous, but in the cultivated variety the poisonous principle has been practically eliminated. The potato belongs, essentially, to the starchy group of foods. If we assume, which is very nearly correct, that the average content of water in different varieties of potatoes at the time they are most suitable for edible purposes is 80 percent, it is found that at least three-fourths of the remaining solid dry matter is starch. The potato contains a trace of sugar and notable quantities of other carbohydrates than starch and sugar, namely, fiber. It also contains a very small proportion of nitrogen and mineral matter.
The potato is grown chiefly in temperate climates. It flourishes particularly well in the northern part of Europe, in England, Scotland, and Ireland, and in the northern portion of the United States. The northern part of Maine, especially, is noted for the production of potatoes of high edible qualities. It grows very well also in the southern part of the United States. The potato may be produced from seed, but that method of propagation has long since ceased to be practiced for agricultural purposes. The potatoes of commerce are produced from the eyes of the tubers. The best results in the growth of potatoes are secured in the loose somewhat sandy soil into which the roots of the plant can easily penetrate and which gives way readily to make place for the growing tuber. Hard, clay soils are unsuited to the growth of this vegetable. The planting is accomplished in the early spring after a thorough preparation of the seed bed by plowing to the usual depth, often subsoiling and reducing the surface of the soil to the proper tilth. The cuttings of potatoes or the whole potatoes are planted in rows to a depth of two or three inches, where they may sprout and even reach the surface at a temperature which at times may fall below the frost point on the surface of the soil. The leaf of the potato, when it has once appeared above the surface of the soil, is very susceptible to the action of frost. If killed at an early stage it may grow again without replanting. The potato is a crop which the farmer may plant early in the spring. There are other varieties which are planted later, even in the middle of summer, and produce good results. The planting season may continue over a period of two or three months. During the growth of the crop by the cultivation of the soil the surface is kept in good tilth, the weeds and grass prevented from growing, and the soil gradually drawn up around the growing tubers with the hoe or plow in the form of ridges. This heaping up of the soil tends to promote the development of the tubers, affording them a loose and more abundant bedding and a greater supply of plant food.
The greatest enemies to which the potato crop is obnoxious are found in the various forms of the potato bug (Doryphora decemlineata), which feed upon their leaves. To prevent the ravages of these insects it becomes necessary to dust over the leaves of the growing plants some powerful insecticide which will destroy the life of the insects feeding upon them. The active ingredient of these insecticides is usually arsenic. Fortunately the growing tuber does not absorb, so far as known, even traces of arsenic, or at least not more than the merest trace, which may be used for insecticidal purposes. It is quite impossible in most localities to secure a crop of potatoes without such treatment. The alternative is a constant inspection of the growing plant and the removal and killing of the bugs as they appear, but this is only practicable over very small areas as its general application would increase the cost of the product beyond the reach of the average consumer.