The following letter refers to Mivart's "Genesis of Species.") Down, September 16th [1871].
I am preparing a new and cheap edition of the "Origin," and shall introduce a new chapter on gradation, and on the uses of initial commencements of useful structures; for this, I observe, has produced the greatest effect on most persons.

Every one of his [Mivart's] cases, as it seems to me, can be answered in a fairly satisfactory manner.

He is very unfair, and never says what he must have known could be said on my side.

He ignores the effect of use, and what I have said in all my later books and editions on the direct effects of the conditions of life and so-called spontaneous variation.

I send you by this post a very clever, but ill-written review from N.America by a friend of Asa Gray, which I have republished.