LETTER 259. TO J.D. HOOKER. Down, June 28th, 1873.

I write a line to wish you good-bye, as I hear you are off on Wednesday, and to thank you for the Dionoea, but I cannot make the little creature grow well. I have this day read Bentham's last address, and must express my admiration of it. (259/1. Presidential address to the Linnean Society, read May 24th, 1873.) Perhaps I ought not to do so, as he fairly crushes me with honour.

I am delighted to see how exactly I agree with him on affinities, and especially on extinct forms as illustrated by his flat-topped tree. (259/2. See page 15 of separate copy: "We should then have the present races represented by the countless branchlets forming the flat-topped summit" of a genealogical tree, in which "all we can do is to map out the summit as it were from a bird's-eye view, and under each cluster, or cluster of clusters, to place as the common trunk an imaginary type of a genus, order, or class according to the depth to which we would go.") My recent work leads me to differ from him on one point--viz., on the separation of the sexes. (259/3. On the question of sexuality, see page 10 of Bentham's address. On the back of Mr. Darwin's copy he has written: "As long as lowest organisms free--sexes separated: as soon as they become attached, to prevent sterility sexes united--reseparated as means of fertilisation, adapted [?] for distant [?] organisms,--in the case of animals by their senses and voluntary movements,--with plants the aid of insects and wind, the latter always existed, and long retained." The two words marked [?] are doubtful. The introduction of freedom or attachedness, as a factor in the problem also occurs in "Cross and Self-fertilisation," page 462. I strongly suspect that sexes were primordially in distinct individuals; then became commonly united in the same individual, and then in a host of animals and some few plants became again separated. Do ask Bentham to send a copy of his address to "Dr. H. Muller, Lippstadt, Prussia," as I am sure it will please him GREATLY.

...When in France write me a line and tell me how you get on, and how Huxley is; but do not do so if you feel idle, and writing bothers you.