Volume I Part 40 (1/2)

(255/1. After speaking of Cope's comparison of acceleration and r.e.t.a.r.dation in evolution to the force of gravity in physical matters Mr.

Hyatt goes on:--)

Now it [acceleration] seems to me to explain less and less the origin of adult progressive characteristics or simply differences, and perhaps now I shall get on faster with my work.

LETTER 256. TO A. HYATT. Down, December 14th [1872].

(256/1. In reply to the above letter (255) from Mr. Hyatt.)

Notwithstanding the kind consideration shown in your last sentence, I must thank you for your interesting and clearly expressed letter. I have directed my publisher to send you a copy of the last edition of the ”Origin,” and you can, if you like, paste in the ”From the Author”

on next page. In relation to yours and Professor Cope's view on ”acceleration” causing a development of new characters, it would, I think, be well if you were to compare the decapods which pa.s.s and do not pa.s.s through the Zoea stage, and the one group which does (according to Fritz Muller) pa.s.s through to the still earlier Nauplius stages, and see if they present any marked differences. You will, I believe, find that this is not the case. I wish it were, for I have often been perplexed at the omission of embryonic stages as well as the acquirement of peculiar stages appearing to produce no special result in the mature form.

(256/2. The remainder of this letter is missing, and the whole of the last sentence is somewhat uncertainly deciphered. (Note by Mr. Hyatt.))

LETTER 257. TO A. HYATT. Down, February 13th, 1877.

I thank you for your very kind, long, and interesting letter. The case is so wonderful and difficult that I dare not express any opinion on it.

Of course, I regret that Hilgendorf has been proved to be so greatly in error (257/1. This refers to a controversy with Sandberger, who had attacked Hilgendorf in the ”Verh. der phys.-med. Ges. zu Wurzburg,” Bd.

V., and in the ”Jahrb. der Malakol. Ges.” Bd. I., to which Hilgendorf replied in the ”Zeitschr. d. Deutschen geolog. Ges.” Jahrb. 1877.

Hyatt's name occurs in Hilgendorf's pages, but we find no reference to any paper of this date; his well-known paper is in the ”Boston. Soc.

Nat. Hist.” 1880. In a letter to Darwin (May 23rd, 1881) Hyatt regrets that he had no opportunity of a third visit to Steinheim, and goes on: ”I should then have done greater justice to Hilgendorf, for whom I have such a high respect.”), but it is some selfish comfort to me that I always felt so much misgiving that I never quoted his paper. (257/2. In the fifth edition of the ”Origin” (page 362), however, Darwin speaks of the graduated forms of Planorbis multiformis, described by Hilgendorf from certain beds in Switzerland, by which we presume he meant the Steinheim beds in Wurtemberg.) The variability of these sh.e.l.ls is quite astonis.h.i.+ng, and seems to exceed that of Rubus or Hieracium amongst plants. The result which surprises me most is that the same form should be developed from various and different progenitors. This seems to show how potent are the conditions of life, irrespectively of the variations being in any way beneficial.

The production of a species out of a chaos of varying forms reminds me of Nageli's conclusion, as deduced from the study of Hieracium, that this is the common mode in which species arise. But I still continue to doubt much on this head, and cling to the belief expressed in the first edition of the ”Origin,” that protean or polymorphic species are those which are now varying in such a manner that the variations are neither advantageous nor disadvantageous. I am glad to hear of the Brunswick deposit, as I feel sure that the careful study of such cases is highly important. I hope that the Smithsonian Inst.i.tution will publish your memoir.

LETTER 258. TO A. DE CANDOLLE. Down, January 18th [1873].

It was very good of you to give up so much of your time to write to me your last interesting letter. The evidence seems good about the tameness of the alpine b.u.t.terflies, and the fact seems to me very surprising, for each b.u.t.terfly can hardly have acquired its experience during its own short life. Will you be so good as to thank M. Humbert for his note, which I have been glad to read. I formerly received from a man, not a naturalist, staying at Cannes a similar account, but doubted about believing it. The case, however, does not answer my query--viz., whether b.u.t.terflies are attracted by bright colours, independently of the supposed presence of nectar?

I must own that I have great difficulty in believing that any temporary condition of the parents can affect the offspring. If it last long enough to affect the health or structure of the parents, I can quite believe the offspring would be modified. But how mysterious a subject is that of generation! Although my hypothesis of pangenesis has been reviled on all sides, yet I must still look at generation under this point of view; and it makes me very averse to believe in an emotion having any effect on the offspring. Allow me to add one word about blus.h.i.+ng and shyness: I intended only to say the habit was primordially acquired by attention to the face, and not that each shy man now attended to his personal appearance.

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 ill.u.s.trated 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 cl.u.s.ter, or cl.u.s.ter of cl.u.s.ters, to place as the common trunk an imaginary type of a genus, order, or cla.s.s 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 s.e.xes. (259/3. On the question of s.e.xuality, see page 10 of Bentham's address. On the back of Mr. Darwin's copy he has written: ”As long as lowest organisms free--s.e.xes separated: as soon as they become attached, to prevent sterility s.e.xes 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 s.e.xes 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.

LETTER 260. TO R. MELDOLA.

(260/1. This letter, with others from Darwin to Meldola, is published in ”Charles Darwin and the Theory of Natural Selection,” by E.B. Poulton, pages 199 et seq., London, 1896.)

Southampton, August 13th, 1873.

I am much obliged for your present, which no doubt I shall find at Down on my return home. I am sorry to say that I cannot answer your question; nor do I believe that you could find it anywhere even approximately answered. It is very difficult or impossible to define what is meant by a large variation. Such graduate into monstrosities or generally injurious variations. I do not myself believe that these are often or ever taken advantage of under nature. It is a common occurrence that abrupt and considerable variations are transmitted in an unaltered state, or not at all transmitted, to the offspring, or to some of them.