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Page:Popular Science Monthly Volume 65.djvu/531

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HEREDITY AND EVOLUTION.

proof. Those who find satisfaction in demonstrations of the obvious may amply indulge themselves by starting various sorts of some annual, say French poppy, in a garden, letting them run to seed, and noticing in a few years how many of the finer sorts are represented; or by sowing an equal number of seeds taken from several varieties of carnation, lettuce or auricula, and seeing in what proportions the fine kinds survive in competition with the common.

Selection is a true phenomenon; but its function is to select, not to create. Many a white-edged poppy may have germinated and perished before Mr. Wilks saved the individual which in a few generations gave rise to the shirleys. Many a black Amphidasys betularia ay have emerged before, some sixty years ago, in the urban conditions of Manchester the black var. doubledayaria found its chance, soon practically superseding the type in its place of origin, extending itself over England, and reappearing even in Belgium and Germany.

Darwin gave us sound teaching when he compared man's selective operations with those of nature. Yet how many who are ready to expound nature's methods have been at the pains to see how man really proceeds? To the domesticated form our fashions are what environmental exigency is to the wild. For years the conventional Chinese primrose threw sporadic plants of the loose-growing stellata variety, promptly extirpated because repugnant to mid-Victorian primness. But when taste, as we say, revived, the graceful star primula was saved by Messrs. Sutton, and a stock raised which is now of the highest fashion. I dare assert that few botanists meeting P. stellata in nature would hesitate to declare it a good species. This and the shirleys precisely illustrate the procedure of the raiser of novelties. His operations start from a definite beginning. As in the case of P. stellata, he may notice a mutational form thrown off perfect from the start, or, as in the shirleys, what catches his attention may be the first indication of that flaw which if allowed to extend will split the type into a host of new varieties each with its own peculiarities and physiological constitution.

Let any one who doubts this try what he can do by selection without such a definite beginning. Let him try from a pure strain of black and white rats to raise a white one by breeding from the whitest, or a black one by choosing the blackest. Let him try to raise a dwarf ('Cupid') sweet pea from a tall race by choosing the shortest, or a crested fowl by choosing the birds with most feathers on their heads. To formulate such suggestions is to expose their foolishness.

The creature is beheld to be very good after, not before its creation. Our domesticated races are sometimes represented as so many incarnations of the breeder's prophetic fancy. But except in recombinations of preexisting characters—now a comprehensible process—and in such intensifications and such finishing touches as involve variations