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seedling potatoes are as liable as old ones to be attacked by the disease; but I found also, that that statement conveys only half the truth. I found that seedling plants of the potato are utterly impervious to the utmost force of the attack of the Peronospora Infestans; absolutely proof against the most extreme virulence of the infection; and that there need not be, if man chooses, a single tuber of the potato in the world, infested by this particuar fungus. And the very simple solution of the paradox is this–there are seedlings and seedlings, just as there are men and men. One man out of two, perhaps, yields to the attack of Asiastic Cholera, the other is wholly unaffected; so with the potato: under conditions favourable to the parasite, about four plants out of five fail to resist the disease absolutely; from one to ten per cent. of the tubers become diseased slightly, and in a few plants, all the tubers become diseased. Thus of my five thousand seedlings of last season, four thousand became more or less diseased; but the lives of the fifth thousand, under the most adverse circumstances which I could devise, proved themselves to be impregnable to the attack of this fungus. Now, if they resisted the disease last year under conditions favourable to the parasite, why should they not resist it this year under conditions favourable to the plant? They have not yet become too old, and I propose to try it. I shall be disappointed if they do not resist the disease for some fifteen or twenty years.
On the title of this paper I have hinted at, or alluded to my belief that the plant may be made to yield 30 or 40 tons per acre. Well, it will be said that this means doubling the productive powers of the temperate zones; the production of a money value, not to be measured in units of a million; but in units, each of which represents the revenues of an Empire. It is perfectly true, that is the proposition–and the question is not, is the matter large; but is it true?
After much research, I have found one man, and one only, who seems to have comprehended the capacity of the plant. I mean the late Thomas Andrew Knight, Esq., "the venerable and talented proprietor of Downton Castle, surrounded by a princely domain of ten thousand acres of rich and beautiful country, who thinks of nothing, but of what may be useful to his fellow-creatures," and who was an original member, and was the second
