I was right to be cautious in supposing you in error about Siphocampylus (no flowers were enclosed). I hope that you will make out whether the pistil presents two definite lengths; I shall be astounded if it does. I do not fully understand your objections to Natural Selection; if I do, I presume they would apply with full force to, for instance, birds. Reflect on modification of Arab-Turk horse into our English racehorse. I have had the satisfaction to tell my publisher to send my "Journal" and "Origin" to your address. I suspect, with your fertile mind, you will find it far better to experiment on your own choice; but if, on reflection, you would like to try some which interest me, I should be truly delighted, and in this case would write in some detail. If you have the means to repeat Gartner's experiments on variations of Verbascum or on maize (see the "Origin"), such experiments would be pre-eminently important. I could never get variations of Verbascum. I could suggest an experiment on potatoes analogous with the case of Passiflora; even the case of Passiflora, often as it has been repeated, might be with advantage repeated. I have worked like a slave (having counted about nine thousand seeds) on Melastoma, on the meaning of the two sets of very different stamens, and as yet have been shamefully beaten, and I now cry for aid. I could suggest what I believe a very good scheme (at least, Dr. Hooker thought so) for systematic degeneration of culinary plants, and so find out their origin; but this would be laborious and the work of years. LETTER 152. TO J.D. HOOKER. Down, 12th [December, 1862]. My good old Friend--