LETTER 589. TO MAXWELL MASTERS. Down, April 7th [1860].

I hope that you will excuse the liberty which I take in writing to you and begging a favour. I have been very much interested by the abstract (too brief) of your lecture at the Royal Institution. Many of the facts alluded to are full of interest for me. But on one point I should be infinitely obliged if you could procure me any information: namely, with respect to sweet-peas. I am a great believer in the natural crossing of individuals of the same species. But I have been assured by Mr. Cattell (589/1. The nurseryman he generally dealt with.), of Westerham, that the several varieties of sweet-pea can be raised close together for a number of years without intercrossing. But on the other hand he stated that they go over the beds, and 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 varieties, and the offspring out of the same pod, instead of being intermediate, was very nearly like the two pure parents; yet in one, there was a trace of the cross, and these crossed peas in the next generation showed still more plainly their mongrel origin. Now, what I want to know is, whether there is much variation in sweet-peas which might be owing to natural crosses. What I should 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, and allow me to quote your authority? It would really be a very great favour and kindness.