Russel Wallace : Alfred Russell Wallace (sic)
W. J. Farmer, Esq.,
Dear Sir,--I presume your question "Why" as to the varying colour of individual hairs and feathers, etc., to form the surface pattern applies to the ultimate cause which enables these patterns to be hereditary, and in the case of birds to be reproduced after moulting yearly.
The purpose or end they serve I have, I think, sufficiently dealt with in my Darwinism, the method by which such useful tints or markings are produced, because useful, is I think clearly explained by the law of natural selection, or survival of the fittest acting through the universal facts of heredity and variation, but the why which goes farther back to the directing agency, which not only brings each special cell of this highly complex structure of a feather into its right position, but further, carries pigments or reproduces surface striae (in the case of the metallic or interference colours) also to their exactly regal place and nowhere else is the mystery which if we knew we should, as Tennyson said of the flower in the wall, "know what God is and what man is."
The idea that cells are all concise beings and go to their right place has been put forward by Butler in his wonderful book Life and Habit, and now even Haeckl seems to adopt it.
All the theories of heredity, including Darwin's Pangenesis do not touch it, and it seems to me as fundamental as Life and Consciousness, and to be absolutely inconceivable by us till we know what Life is and what Spirit is, and it is probable that we must develop in the spirit world some few thousand million years before we get this knowledge, even if then.
Yours very truly,
Copyright: Alfred Russel Wallace Literary Estate.