See "Descent of Man," II., page 141.

Darwin says that no one will attribute the shading of the "eyes" on the wings of the Argus pheasant to the "fortuitous concourse of atoms of colouring-matter." He goes on to say that the development of the ball-and-socket effect by means of Natural Selection seems at first as incredible as that "one of Raphael's Madonnas should have been formed by the selection of chance daubs of paint." The remark of Herschel's, quoted in "Life and Letters," II., page 241, that the "Origin" illustrates the "law of higgledy-piggledy," is probably a conversational variant of the Laputan comparison which gave rise to the passage in the "Descent of Man" (see Letter 130).) You know the oak-leaved variety of the common honeysuckle; I could not persuade a lady that this was not the result of the honeysuckle climbing up a young oak tree! Is this not like the Viola case?
LETTER 244.

TO JOHN LUBBOCK (LORD AVEBURY).

Haredene, Albury, Guildford, August 12th [1871].
I hope the proof-sheets having been sent here will not inconvenience you.

I have read them with infinite satisfaction, and the whole discussion strikes me as admirable.