I should not, however, have written only to trouble you with expressions of sympathy. I desire to ask you one or two questions with reference to an article on Hybridism which I have written for the 'Encyclopædia Britannica,' and the corrected proof of which I send. It is in chief part an epitome of your own chapters upon the subject, and therefore you need not trouble to read the whole, unless you care to see whether I have been sufficiently clear and accurate. But there are two points on which I should like to have your opinion, both for my own benefit and for that of my readers. First, I think it is desirable to append a list of the more important works bearing upon the subject, and if I make such a list I should not like to trust to my own information, lest I should do unwitting injustice to some observing writers. If, therefore, you could, _without taking any special trouble_, jot down from memory the works you think most deserving of mention, I think it would be of benefit to the reading public. _From C. Darwin, Esq._ Down: November 14, 1880. My dear Romanes,--Many thanks for your kind sympathy. My wife's sister was, I fully believe, as good and generous a woman as ever walked this earth. The proof-sheets have not arrived, but probably will to-morrow. I shall like to read them, though I may not be able to do so _very_ quickly, as I am bothered with a heap of little jobs which must be done. I will send by to-day's post a large book by Focke, received a week or two ago, on Hybrids, and which I have not had time to look at, but which I see in Table of Contents includes full history of subject and much else besides. It will aid you far better than I can; for I have now been so long attending to other subjects, and with old age, I fear I could make no suggestions worth anything. Formerly I knew the subject well. Kölreuter, Gärtner, and Herbert are certainly far the most trustworthy authorities. There was also a German, whose name I mention in 'Origin,' who wrote on Hybrid Willows. Naudin, who is often quoted, I have much less confidence in. By the way, Nägeli (whom many think the greatest botanist in Germany) wrote a few years ago on Hybridism; I cannot remember title, but I will hunt for it if you wish. The title will be sure to be in Focke. I quite agree with what you say about Passiflora. Herbert observed an analogous case in Crinum. November 15, 1880.