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in the species, either constantly or occasionally, which are so general, so varied and diverse, and we may add so exquisite and wonderful, that, once propounded, we see that it must be true. What else, indeed, is the meaning and use of sexual reproduction? Not simply increase in numbers; for that is otherwise effectually provided for by budding propagation in plants and many of the lower animals. There are plants, indeed, of the lower sort, in which the whole multiplication takes place in this way, and with great rapidity. These also have sexual reproduction; but in it two old individuals are always destroyed to make a single new one! Here propagation diminishes the number of individuals 50 per cent. Who can suppose that such a costly process as this, and that all the exquisite arrangements for cross-fertilization in hermaphrodite plants, do not subserve some most important purpose? How and why the union of two organisms, or generally of two very minute portions of them, should re-enforce vitality, we do not know and can hardly conjecture. But this must be the meaning of sexual reproduction.
The conclusion of the matter from the scientific point of view is, that sexually propagated varieties, or races, although liable to disappear through change, need not be expected to wear out, and there is no proof that they do; but, that non-sexually propagated varieties, though not liable to change, may theoretically be expected to wear out, but to be a very long time about it."—American Journal of Science and Arts, February, 1875.
From the foregoing and indeed from all the text books on Botany it is clear that Mr. Knight's biographer was mistaken, when he imagined that his views were "almost universally adopted." However that may be, I hold fast by my own text, "that if cutting a plant into two equal parts, and growing it in different parts of space, do not constitute it two individuals, neither can cutting it into two unequal parts, and calling one the stem and the other the scion, do so." In neither case is there any new birth, nor consequently any rejuvenation of life and all the analogies of nature point to this conclusion.
Notwithstanding alternate generation, and multiplication by fission, &c., the sexual union, I believe, is at the bottom of the life of the individual; and I also, like Mr. Sisley, am pre-
