“We see in these facts some deep organic bond, prevailing throughout space and time, over the same areas of land and water, and independent of their physical condition. The naturalist must feel little curiosity who is not led to inquire what this bond is.
“This bond, on my theory, is simply inheritance, that cause which alone,” &c. (p. 350).
This passage was altered in 1869 to “The bond is simply inheritance.” The paragraph concludes, “On this principle of inheritance with modification, we can understand how it is that sections of genera . . . are confined to the same areas,” &c.
Again:—
“He who rejects it rejects the vera causa of ordinary generation,” &c. (p. 352).
We naturally ask, Why call natural selection the “main means of modification,” if “ordinary generation” is a vera causa?
Again:—
“In discussing this subject, we shall be enabled at the same time to consider a point equally important for us, namely, whether the several distinct species of a genus, which on my theory have all descended from a common ancestor, can have migrated (undergoing modification during some part of their migration) from the area inhabited by their progenitor” (p. 354).
The words “on my theory” became “on our theory” in 1869.
Again:—