Dear Sir
I hope that you will excuse the liberty which I take in writing to you & begging a favour.— I have been very much interested by the abstract (too brief) of your Lecture at Royal Institution.2 Many of the facts alluded to are full of interest for me. But on one point I shd. be infinitely obliged if you could procure me any information; namely with respect to Sweet Peas.3 I am a great believer in the natural crossing of individuals of the same species. But I have been assured by Mr Cattell of Westerham, that the several vars. of Sweet Pea can be raised close together for a number of years without intercrossing.4 But on other hand he stated that they go over the beds, & pull up any false plant which they very naturally attribute to wrong seeds getting mixed in the lot.— After many failures I succeeded in artificially crossing two vars. & the offspring out of the same pod, instead of being intermediate, were very nearly like the two pure parents; yet in one, there was a trace of the cross & these crossed peas in the next generation showed still more plainly their mongrel origin.—
Now what I want to know whether there is much variation in Sweet Peas which might be owing to natural crosses. What I shd. expect would be that they would keep true for many years, but that occasionally, perhaps at long intervals, there would be a considerable amount of crossing of the varieties grown close together. Can you give or obtain from your Father any information on this head & allow me to quote your authority?5 It would really be a very great favour & kindness.—
I hope that you will forgive me asking you thus to oblige me, & believe me dear Sir | Yours very faithfully | C. Darwin
P.S. | As it seems you have read my “Origin”, I need not say that, if you have leisure, how infinitely I shd be obliged for any facts bearing on any of the points discussed.—6
Please cite as “DCP-LETT-2749,” in Ɛpsilon: The Charles Darwin Collection accessed on