You will be weary of notes from me about the little book of yours. It is lucky for me that I expressed, before reading No. VI. (157/1. "Lectures to Working Men," No. VI., is a critical examination of the position of the "Origin of Species" in relation to the complete theory of the "causes of the phenomena of organic nature."), my opinion of its absolute excellence, and of its being well worth wide distribution and worth correction (not that I see where you could improve), if you thought it worth your valuable time. Had I read No. VI., even a rudiment of modesty would, or ought to, have stopped me saying so much. Though I have been well abused, yet I have had so much praise, that I have become a gourmand, both as to capacity and taste; and I really did not think that mortal man could have tickled my palate in the exquisite manner with which you have done the job. So I am an old ass, and nothing more need be said about this. I agree entirely with all your reservations about accepting the doctrine, and you might have gone further with further safety and truth. Of course I do not wholly agree about sterility. I hate beyond all things finding myself in disagreement with any capable judge, when the premises are the same; and yet this will occasionally happen. Thinking over my former letter to you, I fancied (but I now doubt) that I had partly found out the cause of our disagreement, and I attributed it to your naturally thinking most about animals, with which the sterility of the hybrids is much more conspicuous than the lessened fertility of the first cross. Indeed, this could hardly be ascertained with mammals, except by comparing the products of [their] whole life; and, as far as I know, this has only been ascertained in the case of the horse and ass, which do produce fewer offspring in [their] lifetime than in pure breeding. In plants the test of first cross seems as fair as test of sterility of hybrids. And this latter test applies, I will maintain to the death, to the crossing of varieties of Verbascum, and varieties, selected varieties, of Zea. (157/2. See Letter 156.) You will say Go to the Devil and hold your tongue. No, I will not hold my tongue; for I must add that after going, for my present book, all through domestic animals, I have come to the conclusion that there are almost certainly several cases of two or three or more species blended together and now perfectly fertile together. Hence I conclude that there must be something in domestication,--perhaps the less stable conditions, the very cause which induces so much variability,--which eliminates the natural sterility of species when crossed. If so, we can see how unlikely that sterility should arise between domestic races. Now I will hold my tongue. Page 143: ought not "Sanscrit" to be "Aryan"? What a capital number the last "Natural History Review" is! That is a grand paper by Falconer. I cannot say how indignant Owen's conduct about E. Columbi has made me. I believe I hate