Considering what Geology teaches us, the argument from the supposed immutability of specific types seems to me much the same as if, in a nation which had no old writings, some wise old savage was to say that his language had never changed; but my metaphor is too long to fill up.
Pray believe me, dear Sir, yours very sincerely obliged, C. DARWIN.
1866.
[The year 1866 is given in my father's Diary in the following words:—
"Continued correcting chapters of 'Domestic Animals.'
March 1st.—Began on 4th edition of 'Origin' of 1250 copies (received for it 238 pounds), making 7500 copies altogether.
May 10th.—Finished 'Origin,' except revises, and began going over Chapter XIII. of 'Domestic Animals.'
November 21st.—Finished 'Pangenesis.'
December 21st.—Finished re-going over all chapters, and sent them to printers.
December 22nd.—Began concluding chapter of book."