But undoubtedly this was the general belief when the first edition of the present work appeared...Now things are wholly changed, and almost every naturalist admits the great principle of evolution."A small correction introduced into this sixth edition is connected with one of his minor papers: "Note on the habits of the Pampas Woodpecker."(Zoolog. Soc. Proc. 1870.) In the fifth edition of the 'Origin,' page 220, he wrote:--"Yet as I can assert not only from my own observation, but from that of the accurate Azara, it [the ground woodpecker] never climbs a tree." The paper in question was a reply to Mr. Hudson's remarks on the woodpecker in a previous number of the same journal. The last sentence of my father's paper is worth quoting for its temperate tone: "Finally, I trust that Mr. Hudson is mistaken when he says that any one acquainted with the habits of this bird might be induced to believe that I 'had purposely wrested the truth' in order to prove my theory. He exonerates me from this charge; but I should be loath to think that there are many naturalists who, without any evidence, would accuse a fellow-worker of telling a deliberate falsehood to prove his theory." In the sixth edition, page 142, the passage runs "in certain large districts it does not climb trees." And he goes on to give Mr. Hudson's statement that in other regions it does frequent trees.
One of the additions in the sixth edition (page 149), was a reference to Mr. A. Hyatt's and Professor Cope's theory of "acceleration." With regard to this he wrote (October 10, 1872) in characteristic words to Mr. Hyatt:--"Permit me to take this opportunity to express my sincere regret at having committed two grave errors in the last edition of my 'Origin of Species,' in my allusion to yours and Professor Cope's views on acceleration and retardation of development. I had thought that Professor Cope had preceded you; but I now well remember having formerly read with lively interest, and marked, a paper by you somewhere in my library, on fossil Cephalapods with remarks on the subject. It seems also that I have quite misrepresented your joint view. This has vexed me much. I confess that I have never been able to grasp fully what you wish to show, and I presume that this must be owing to some dulness on my part."Lastly, it may be mentioned that this cheap edition being to some extent intended as a popular one, was made to include a glossary of technical terms, "given because several readers have complained...that some of the terms used were unintelligible to them." The glossary was compiled by Mr. Dallas, and being an excellent collection of clear and sufficient definitions, must have proved useful to many readers.]
CHARLES DARWIN TO J.L.A. DE QUATREFAGES.
Down, January 15, 1872.
My dear Sir, I am much obliged for your very kind letter and exertions in my favour. Ihad thought that the publication of my last book ['Descent of Man'] would have destroyed all your sympathy with me, but though I estimated very highly your great liberality of mind, it seems that I underrated it.
I am gratified to hear that M. Lacaze-Duthiers will vote (He was not elected as a corresponding member of the French Academy until 1878.) for me, for I have long honoured his name. I cannot help regretting that you should expend your valuable time in trying to obtain for me the honour of election, for I fear, judging from the last time, that all your labour will be in vain. Whatever the result may be, I shall always retain the most lively recollection of your sympathy and kindness, and this will quite console me for my rejection.
With much respect and esteem, I remain, dear Sir, Yours truly obliged, CHARLES DARWIN.
P.S.--With respect to the great stress which you lay on man walking on two legs, whilst the quadrumana go on all fours, permit me to remind you that no one much values the great difference in the mode of locomotion, and consequently in structure, between seals and the terrestrial carnivora, or between the almost biped kangaroos and other marsupials.
CHARLES DARWIN TO AUGUST WEISMANN. (Professor of Zoology in Freiburg.)Down, April 5, 1872.
My dear Sir, I have now read your essay ('Ueber den Einfluss der Isolirung auf die Artbildung.' Leipzig, 1872.) with very great interest. Your view of the 'Origin' of local races through "Amixie," is altogether new to me, and seems to throw an important light on an obscure problem. There is, however, something strange about the periods or endurance of variability.
I formerly endeavoured to investigate the subject, not by looking to past time, but to species of the same genus widely distributed; and I found in many cases that all the species, with perhaps one or two exceptions, were variable. It would be a very interesting subject for a conchologist to investigate, viz., whether the species of the same genus were variable during many successive geological formations. I began to make enquiries on this head, but failed in this, as in so many other things, from the want of time and strength. In your remarks on crossing, you do not, as it seems to me, lay nearly stress enough on the increased vigour of the offspring derived from parents which have been exposed to different conditions. Ihave during the last five years been making experiments on this subject with plants, and have been astonished at the results, which have not yet been published.