This now stands—­“The explanation is to a large extent simple, on the theory of the selection of successive, slight modifications.”  I do not like “a large extent” of simplicity; but, waiving this, the point at issue is not whether the ordinary course of things ensures a quasi-selection of the types that are best adapted to their surroundings, with accumulation of modification in various directions, and hence wide eventual difference between species descended from common progenitors—­no evolutionist since 1750 has doubted this—­but whether a general principle underlies the modifications from among which the quasi-selection is made, or whether they are destitute of such principle and referable, as far as we are concerned, to chance only.  Waiving this again, we note that the theories of independent creation and of natural selection are contrasted, as though they were the only two alternatives; knowing the two alternatives to be independent creation and descent with modification, we naturally took natural selection to mean descent with modification.

Again:-

“On the theory of natural selection we can satisfactorily answer these questions” (p. 437).

“Satisfactorily” now stands “to a certain extent.”

Again:-

“On my view these terms may be used literally” (pp. 438, 439).

“On my view” became “according to the views here maintained such language may be,” &c., in 1869.

Again:-

“I believe all these facts can be explained as follows, on the view of descent with modification” (p. 443).

This sentence now ends at “follows.”

Again:-

“Let us take a genus of birds, descended, on my theory, from some one parent species, and of which the several new species have become modified through natural selection in accordance with their divers habits” (p. 446).

The words “on my theory” were cut out in 1869, and the passage now stands, “Let us take a group of birds, descended from some ancient form and modified through natural selection for different habits.”

Again:-

“On my view of descent with modification, the origin of rudimentary organs is simple” (p. 454).

“On my view” became “On the view” in 1869.

Again:-

“On the view of descent with modification,” &c. (p. 455).

Again:-

“On this same view of descent with modification all the great facts of morphology become intelligible” (p. 456).

Again:-

“That many and grave objections may be advanced against the theory of descent with modification through natural selection, I do not deny” (p. 459).