On Germinal Selection as a Source of Definite Variation

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On Germinal Selection as a Source of Definite Variation is by August Weismann. The text quotes Heinrich Hertz, the discoverer of electric undulations, as saying that we form inward representations or constructs of outward objects. The writer says that in his theory of heredity the determinants are representative models, or constructs, which may be conceived as indefinitely fashioned packages of units (biophores).

The writer supposes that the ancestral species of a certain forest-butterfly habitually reposed on branches covered with dry or rotten leaves, and would assume on its under surface a protective coloring tending toward similarity with such leaves. If the descendants of the species were compelled, no matter from what cause, to adopt the habit of resting on the green-leafed branches higher up, the brown coloring would act less protectively than the shades verging towards green.