On the following page (page 243) a passage (not marked by Mr. Darwin)
emphasises the limitation which Prichard ascribed to the results of
variation and inheritance:--

"Even those physiologists who contend for what is termed the indefinite
nature of species admit that they have limits at present and under ordinary
circumstances. Whatever diversities take place happen without breaking in
upon the characteristic type of the species. This is transmitted from
generation to generation: goats produce goats, and sheep, sheep."

The passage on page 242 occurs in the reprint of the 1836-7 edition which
forms part of the 1841-51 edition, but is not there marked by Mr. Darwin.
He notes at the end of Volume I. of the 1836-7 edition: "March, 1857. I
have not looked through all these [i.e. marked passages], but I have gone
through the later edition"; and a similar entry is in Volume II. of the
third edition. It is therefore easy to understand how he came to overlook
the passage on page 242 when he began the fuller statement of his species
theory which is referred to in the "Life and Letters" as the "unfinished
book." In the historical sketch prefixed to the "Origin of Species"
writers are named as precursors whose claims are less strong than
Prichard's, and it is certain that Mr. Darwin would have given an account
of him if he had thought of him as an evolutionist.

The two following passages will show that Mr. Darwin was, from his
knowledge of Prichard's books, justified in classing him among those who
did not believe in the mutability of species:

"The various tribes of organised beings were originally placed by the
Creator in certain regions, for which they are by their nature peculiarly