The theory of degeneration, without doubt, will assist us to explain the why and wherefore of the potato rot. But this is not all; the community want to know the cause of this degeneracy. We have spent some time in the investigation of this subject, and now give the public, in a condensed form, our opinion of this matter. We may err, but our progress is towards the full discovery of the _direct cause_, and the ways and means best adapted to prevent this sad calamity. The potato came into existence at a certain period in the history of the world. After its discovery, it was taken from the mother soil, the land of its nativity, planted in different parts of the world, and grew to apparent perfection. Our opinion is, that the transplanting was one of the causes of this degeneracy. It is generally known that indigenous plants do not thrive so well on foreign soil as in their native; for example, the plants of the sunny south cannot be made to flourish here in the same degree of perfection as at the south; they require the genial warmth of the sun's rays, which our northern climates lack. The soil, too, mast be adapted to each particular plant. It is true we do cultivate them by ingenuity and chemical agency; yet they seldom equal the original. Need we ask the farmer if he can, from the soil of New England, produce a St. Michael orange equal to one grown on its native soil? or if a squash will grow in the deserts of Arabia? All vegetables, as well as animals, possess a certain amount of vital power, which enables them to resist, to a certain degree, all encroachments on their healthy operations. The potato, having been deprived, in some measure, of its essential element, lost its reciprocal equilibrium, and has ever since been a prey to whatever destructive agents may be present, whether they exist in the soil or atmosphere. Yet we conceive that its total destruction is dependent on another cause, which has been entirely overlooked; for, in spite of the gradual deterioration alluded to, the potato will, for a number of years, continue to keep up a low form of vitality, and result in something like a potato. In order to comprehend the subject, let us, for a moment, consider the conditions necessary for the germination and perfection of vegetable bodies. We shall then be able to decide as to whether or not we have complied with such conditions. The first condition is, we must have _a perfect germ_; secondly, _a ripe seed_; and lastly, _nutrimental agents in the sail, composed of carbon, hydrogen, and oxygen_.