Summary

Believes, with CD, that extinction may be an important factor in explaining plant distributions, but sees no reason why the several species of a genus must ever have had a common or continuous area. "Convince me of that, or show me any good grounds for it … and I think you would carry me a good way with you". It is just such people as AG that CD has to satisfy and convince.

Feels that the crossing of individuals is important in repressing variation and perhaps in perpetuating the species, but instances some plants in which it cannot, apparently, take place.

Summary

Declines invitation to ride because he is "so very subject to headache".

Summary

Has written down what he gathered from HF on Tibetan dogs. Would welcome a few more details at any time, as he knows of nothing parallel to it.

Summary

Writing section on large and small genera [for Natural selection, ch. 4].

Huxley supersedes Owen on parthenogenesis.

Buckle’s History of civilisation in England extremely interesting.

Summary

Thanks him for specimens collected.

Comments on JED’s voyage [on H.M.S. Terror, 1839–43].

Mentions activities of old Beagle crew.

Summary

Comments on DM’s ["Drift deposits of west of England", Q. J. Geol. Soc. Lond. 35 (1879): 425–55].

Summary

Comments on David Milne’s paper ["On the parallel roads of Lochaber" (1847), Trans. R. Soc. Edinburgh 16 (1849): 395–418]. CD still believes in marine origin. Rejects barrier of detritus at mouth of Glen Roy. If roads were formed by lake, it must have been ice-lake.

Comments on evidence of glaciers and icebergs in North Wales. Thinks pass caused by tidal channel, not river. Suggests that RC make altitude measurements at various points.

Summary

Queries on ratios of species to genera on southern islands. CD’s observations on distribution of Galapagos organisms, and on S. American fossils, and facts he has gathered since, lead him to conclusion that species are not immutable; "it is like confessing a murder".

Summary

Sends results of chemical tests on specimens [of salt, see South America, pp. 73–5].

Encloses abstract from Justus Liebig on composition of bones and their ability to withstand decay.

Summary

Asks GB for help in clearing up his problems about Leguminosae, in connection with his "wild bit of speculation on the crossing of plants" [see Natural selection, p. 71].

Summary

CD makes progress with barnacles. Describes "supplemental" males in detail. In working out metamorphosis, their crustacean homologies followed automatically.

CD opposes appending first describer’s name to specific name.

Summary

Reports some observations on the fertilisation of wheat which WED might follow up.

Summary

Has just completed Volcanic islands.

Sends queries on Galapagos flora in particular and island floras in general; also on relationship of wide-ranging species to wide-ranging genera.

Summary

Thanks for case of inherited malconformation.

Summary

Observations from a fortnight in Lochaber. Found the entrance to Loch Treig to present the clearest evidence of intense glacial action. States, in contradiction of David Milne-Home, that there is glacial scoring in Glen Spean, as Louis Agassiz described, and moraine around the mouth of Loch Treig. There is little sign of water erosion on the rocks crossed by the lines in Glen Roy. Believes the smoothed rocks at the eastern end of Loch Laggan are due to flow from the lake and not tidal action. The lines in Glen Roy are too neat for a lake shore subject to tides. Given the glacial scoring sweeping round from Glen Spean into Glen Treig, and all the boulders, TFJ is astonished that anyone could deny that there had been glaciers there. [See 3247.]

Summary

CD gratified that ED wants to translate his Journal. Will send a copy of Coral reefs, which contains a fuller treatment of topic. Perhaps ED would insert a note to this effect. Can lend woodcuts from Coral reefs if ED wants. CD will send a few corrections; he wants to amend way he criticised Agassiz’s glacier theory.

He is also enclosing a questionnaire concerning differences between races or varieties and species, about which he intends to publish sometime.

Summary

Seeks permission to make another visit to Addiscombe [Military College] to see again the model of St Helena. He needs to correct proportion of some geological sections in his Geology [see Volcanic islands, ch. 4].

Summary

Did not intend his last letter as criticism. Is sure CD would not "wriggle out" of a difficulty if he had observed it.

Sends CD a wasps’ nest.

Summary

Has seen lately a true ruminant with the two central metacarpals distinct. It was the foot of an Anoplotherium in a recent ruminant.

Summary

Sex ratios in cattle and sheep.