The potato requires but a small quantity of moisture to develop the germinating principle; for we have every day evidences of its ability to send forth its fibres, even in the open air. Now, the premature development of these fibrous radicles, or roots, debilitates the tuber; in short, we have a sick potato. Is the potato, under such circumstances, a perfect germ? No. If you examine the potato, with its roots and stem, you will find the cutis, or skin, and mucous membrane. This external skin, _including that of plant, stalk, leaf, and ball_, is to the potato what the skin and lungs are to animals; they, each of them, absorb atmospheric food, and throw off excrementitious matter; the roots and fibres are to the vegetable what the alimentary canal is to the animal. A large portion of the food of vegetables is found in the soil, and enters the vegetable system, through its capillary circulation, by the process of imperceptible elimination and absorption. Now, you must bear in mind that the fibres, stem, and leaves are delicate and tender organs; they are studded with millions of little pores, covered with a membrane of delicate texture, easily lacerated. When these delicate organs are rudely torn off or lacerated, the potato immediately gives evidence of the encroachments of disease; it shrinks, withers, and, although the soil abounds in all that is necessary for its growth and future development, it is not in a fit state to carry on the chemico-vital process. We often take the potato from the soil with a view of preserving it for seed, without any definite knowledge of the exact time of its maturity; as the season arrives for again replanting, the fibres are torn off, and the potato itself is often cut up into two or three pieces; sometimes, however, the smaller potatoes are used for seed. Both practices are open to strong objection. Oftentimes the cut surfaces of the potato are exposed to atmospheric air; evaporation commences, they lose their firm texture, and are more fit for swine than for planting.