[The next letter is of interest, as giving the beginning of the connection which arose between my father and Professor Victor Carus. The translation referred to is the third German edition made from the fourth English one. From this time forward Professor Carus continued to translate my father's books into German. The conscientious care with which this work was done was of material service, and I well remember the admiration (mingled with a tinge of vexation at his own short-comings) with which my father used to receive the lists of oversights, etc., which Professor Carus discovered in the course of translation. The connection was not a mere business one, but was cemented by warm feelings of regard on both sides.] CHARLES DARWIN TO VICTOR CARUS. Down, November 10, 1866. My dear Sir, I thank you for your extremely kind letter. I cannot express too strongly my satisfaction that you have undertaken the revision of the new edition, and I feel the honour which you have conferred on me. I fear that you will find the labour considerable, not only on account of the additions, but I suspect that Bronn's translation is very defective, at least I have heard complaints on this head from quite a large number of persons. It would be a great gratification to me to know that the translation was a really good one, such as I have no doubt you will produce. According to our English practice, you will be fully justified in entirely omitting Bronn's Appendix, and I shall be very glad of its omission. A new edition may be looked at as a new work... You could add anything of your own that you liked, and I should be much pleased. Should you make any additions or append notes, it appears to me that Nageli "Entstehung und Begriff," etc. ('Entstehung und Begriff der Naturhistorischen Art.' An address given at a public meeting of the 'R. Academy of Sciences' at Munich, March 28, 1865.), would be worth noticing, as one of the most able pamphlets on the subject. I am, however, far from agreeing with him that the acquisition of certain characters which appear to be of no service to plants, offers any great difficulty, or affords a proof of some innate tendency in plants towards perfection. If you intend to notice this pamphlet, I should like to write hereafter a little more in detail on the subject. ... I wish I had known when writing my Historical Sketch that you had in 1853 published your views on the genealogical connection of past and present forms. I suppose you have the sheets of the last English edition on which I marked with pencil all the chief additions, but many little corrections of style were not marked. Pray believe that I feel sincerely grateful for the great service and honour which you do me by the present translation. I remain, my dear Sir, yours very sincerely, CHARLES DARWIN. P.S.--I should be VERY MUCH pleased to possess your photograph, and I send mine in case you should like to have a copy.