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before exhaustion of the full allotment of life, and explains why the plants derived by cuttings from the old stem live longer—their circulation is not destroyed by the growth of heart-wood. With regard to the potato,—the roots, stems, and foliage die annually, the seed is thrown away, the germs in the tubers are planted in fresh soil, and they are always placed in a position to form new absorbing organs (roots) and so to live out life to the end—a period, I think, of about 60 or 80 years. That is, they may live to the end of their term of life; but in point of fact, like other individuals, they are almost invariably cut off by disease or some adverse influence which their vitality, enfeebled by old age, is unable to withstand. Again, it is said that the vine has been handed down to us by a succession of cuttings from the time of the Romans. If so, this merely proves that the vine has a life of, at least, so many centuries, a matter of no moment in the consideration of this question, and nothing extraordinary in itself, seeing that some original plants have lived much longer, some thousands of years longer, than any succession of cuttings, the vine included. And this law of sexual reproduction, if the only true law of reproduction, must of necessity affect the vine and the sugar-cane as well as the potato. Grafted fruit-trees, &c., of course come under the law; but that is a matter of comparatively infinitely small importance.
We do not yet know the duration of the life of the potato, or of any perennial plant (and I submit that the potato is really a perennial). It varies no doubt in different individuals; but it seems absurd to suppose that its powers of vegetative multiplication are infinite, and that the process of cutting it to pieces and planting it in the earth periodically, will have the effect of conferring upon it immortality. On the contrary, the current vehicle of life–the existing plant—dies annually, subtracting one year of life from the original stock, while the life itself is carried forward in the successive annual buds and tubers, and undergoes annual depletion until exhausted.
Last spring (1875), by dint of advertisements, here and in England, and by procuring the names of large cultivators of the plant, I succeeded in inducing about 150 people to try to grow the potato from the seed which I sent them. In not one case out of the 150 was the result worth one farthing. Having never grown a potato from the seed myself, I could only give them such instructions as I
