As to the second, I have always felt the difficulty of accounting for the enormous development of the peacock’s train, the bird of paradise plumes, the long wattle of the bell bird, the enormous tail-feathers of the Guatemalan trogon, of some humming-birds, etc. etc. etc.  The beginnings of all these I can explain as recognition marks, and this explains also their distinctive character in allied species, but it does not explain their growing on and on far beyond what is needful for recognition, and apparently till limited by absolute hurtfulness.  It is a relief to me to have “germinal selection” to explain this.

I do not, however, think it at all necessary to explain adaptations, however complex.  Variation is so general and so large, in dominant species, and selection is so tremendously powerful, that I believe all needful adaptation may be produced without it.  But, if it exists, it would undoubtedly hasten the process of such adaptation and would therefore enable new places in the economy of nature to be more rapidly filled up.

I was thinking of writing a popular exposition of the new theory for Nature, but have not yet found time or inclination for it.  I began reading “Germinal Selection” with a prejudice against it.  That prejudice continued through the first half, but when I came to the idea itself, and after some trouble grasped the meaning and bearing of it, I saw the work it would do and was a convert at once.  It really has no relation to Lamarckism, and leaves the non-heredity of acquired characters exactly where it was.—­Yours very truly,

ALFRED R. WALLACE.

* * * * *

The next letter relates to the great controversy then being carried on with respect to Weismann’s doctrine of the non-inheritance of “acquired” characters, which doctrine implied complete rejection of the last trace of Lamarckism from Darwinian evolution.  Wallace ultimately accepted the Weismannian teaching.  Darwin had no opportunity during his lifetime of considering this question, which was raised later in an acute form by Weismann.

TO PROF.  MELDOLA

Parkstane, Dorset.  January 6, 1897.

My dear Meldola,—­The passage to which you refer in the “Origin” (top of p. 6) shows Darwin’s firm belief in the “heredity of acquired variations,” and also in the importance of definite variations, that is, “sports,” though elsewhere he almost gives these up in favour of indefinite variations; and this last is now the view of all Darwinians, and even of many Lamarckians.  I therefore always now assume this as admitted.  Weismann’s view as to “possible variations” and “impossible variations” on p. 1 of “Germinal Selection” is misleading, because it can only refer to “sports” or to “cumulative results,” not to “individual variations” such as are the material Natural Selection acts on.