Reflect on the long succession of embryological changes in every animal. Does a bud ever produce cotyledons or embryonic leaves? I have been much interested by your remark on inheritance at corresponding ages; I hope you will, as you say, continue to attend to this. Is it true that female Primula plants always produce females by parthenogenesis? (151/3. It seems probable that Darwin here means vegetative reproduction.) If you can answer this I should be glad; it bears on my Primula work. I thought on the subject, but gave up investigating what had been observed, because the female bee by parthenogenesis produces males alone. Your paper has told me much that in my ignorance was quite new to me. Thanks about P. scotica. If any important criticisms are made on the Primula to the Botanical Society, I should be glad to hear them. If you think fit, you may state that I repeated the crossing experiments on P. sinensis and cowslip with the same result this spring as last year--indeed, with rather more marked difference in fertility of the two crosses. In fact, had I then proved the Linum case, I would not have wasted time in repetition. I am determined I will at once publish on Linum...
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--
How kind you have been to give me so much of your time! Your letter is of real use, and has been and shall be well considered. I am much pleased to find that we do not differ as much as I feared. I begin my book with saying that my chief object is to show the inordinate scale of variation; I have especially studied all sorts of variations of the individual. On crossing I cannot change; the more I think, the more reason I have to believe that my conclusion would be agreed to by all practised breeders. I also greatly doubt about variability and domestication being at all necessarily correlative, but I have touched on this in "Origin." Plants being identical under very different conditions has always seemed to me a very heavy argument against what I call direct action. I think perhaps I will take the case of 1,000 pigeons (152/1. See Letter 146.) to sum up my volume; I will not discuss other points, but, as I have said, I shall recur to your letter. But I must just say that if sterility be allowed to come into play, if long-beaked be in the least degree sterile with short-beaked, my whole case is altered. By the way, my notions on hybridity are becoming considerably altered by my dimorphic work.