(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 pass and do not pass through the Zoea stage, and the one group which does (according to Fritz Muller) pass 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 shells is quite astonishing, 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 Institution will publish your memoir.
LETTER 258. TO A. DE CANDOLLE. Down, January 18th .
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 butterflies, and the fact seems to me very surprising, for each butterfly 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 butterflies are attracted by bright colours, independently of the supposed presence of nectar?