and XIII., you go much further with me (though a little way) than I ever anticipated, and am much pleased at the result.

But on the whole I am disappointed, because it seems to me that you do not understand what I mean by Natural Selection, as shown at page 11 (110/2.

Harvey speaks of the perpetuation or selection of the useful, pre-supposing "a vigilant and intelligent agent," which is very much like saying that an intelligent agent is needed to see that the small stones pass through the meshes of a sieve and the big ones remain behind.) of your letter and by several of your remarks.

As my book has failed to explain my meaning, it would be hopeless to attempt it in a letter.

You speak in the early part of your letter, and at page 9, as if I had said that Natural Selection was the sole agency of modification, whereas I have over and over again, ad nauseam, directly said, and by order of precedence implied (what seems to me obvious) that selection can do nothing without previous variability (see pages 80, 108, 127, 468, 469, etc.), "nothing can be effected unless favourable variations occur." I consider Natural Selection as of such high importance, because it accumulates successive variations in any profitable direction, and thus adapts each new being to its complex conditions of life.