Page:Popular Science Monthly Volume 48.djvu/523

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THE STUDY OF INHERITANCE.
481

iar word is chosen with so much, aptness that it does its duty and presents the new conception better than a compound from two or three dead languages. The terms "mid-parent" or "mid," "fraternity," "nurture," and "Q" can not mislead or convey any idea except the right one.

The reviewer's debt to Galton is very great, and it is acknowledged with gratitude. Such acquaintance with the statistical method as he possesses he owes to the study of these books; especially the ones on Hereditary Genius (1869), on Natural. Inheritance (1889), and on Finger Prints (1893).

The attempt to question Galton's generalizations may therefore seem ungracious and presumptuous, but the uncertainties of vital statistics are proverbial; and it is not impossible that Galton's data may fail to cover all the ground needed to prove his general conclusions.

One of these generalizations is so far-reaching that, if it is well founded, it must lead to profound and fundamental changes in our view of the origin of species.

According to Darwin and Wallace, specific identity in living things is the outcome of the extermination, in the struggle for existence, of the individuals which depart too widely from that "type" which is on the whole best adapted to existing conditions. As these conditions change, the "type" is also slowly modified through a change in the character of this process of extermination. According to this view, the "type" is the outcome of the statistical "law of error," or the deviation from the mean, which holds good in the environment; and while the "events" are properties of the organism, the type is fixed by the external world, and not by anything in the organism itself.

Galton holds that specific identity is not due to the process of extermination, but to "organic stability." As I understand him, he holds that this fills up the gaps made by extermination, and thus keeps the type intact.

This "principle of stability," which is held to result in the permanency of types, is said to be quite independent of selection. "Genera and species may be formed without the slightest aid from either natural or sexual selection." "Organic stability is the primary factor by which the distinctions between genera are maintained."

Galton holds, furthermore, not only that specific stability is independent of selection, but that selection is "scarcely competent" to effect a change of type "by favoring mere varieties"—that is, by the extermination of the ordinary slight differences between individuals; and that it is only when a "sport" has made its appearance, only when the type has actually changed, that selection can exert any influence. According to this view, the