Comments on an article in Edinburgh Review [by David Brewster, 67 (1838): 271-308] on Comte's Philosophie positive.
Discusses falsity of Élie de Beaumont's views of contemporaneous parallel lines of elevation and subsidence.
Owen's views of relationship of reptiles to birds.
On "question of species" CD has filled notebook after notebook with facts, "which begin to group themselves clearly under sub-laws".
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.
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".
Asks whether LJ can throw light on this subject: "What are the checks and what the periods of life by which the increase of any given species is limited?" CD has been driven to conclude that species are mutable; allied species are co-descendants from common stocks.
Origin of Antarctic brash ice.
Further on case of Lycopodium: does JDH know any genera of plants whose species are variable in one continent but not in another? Discussion on variations between floras as regards species richness, and factors affecting geographical distribution. On species, CD expects "that I shall be able to show even to sound naturalists that there are two sides to the question of the immutability of species; - that facts can be viewed and grouped under the notion of allied species having descended from common stocks". Mentions books and papers for and against species mutability. CD believes past absurd ideas arose from no one's having approached subject on side of variation under domestication.
Would like to see Clarke's paper
and would welcome visit from JDH.
Going to Shrewsbury on Monday.
Means to attempt the question of species: "though I shall get more kicks than half-pennies, I will, life serving, attempt my work".
What does CD think of A. R. Wallace's paper in the Annals & Magazine of Natural History ["On the law which has regulated the introduction of new species", n.s. 16 (1855): 184-96]? EB considers it good on the whole.
Japanned variety of peacock.
Regional variations in bird species.
EB has little faith in the aboriginal wildness of the Chillingham cattle.
Races of humped cattle of India, China, and Africa.
Indian and Malayan gigantic squirrels, with various races remaining true to their colour, would afford capital data for Wallace, as would the local varieties of certain molluscs. Has Wallace's lucid collation of facts unsettled CD's ideas regarding the persistence of species?
Bengal hybrid race of geese is very uniform in colour and as prolific as the European tame goose [see Natural selection, p. 439].
Will see what he can do for CD with regard to domestic pigeons.
Hopes GHKT will publish on variations in plant species at different elevations. Asks about variations among plants on heights of Ceylon.
Promises to publish on the species question.
Asks for pigeons' skins from India or Ceylon, and for ducks' skeletons. Mentions help promised by E. F. Kelaart.
Agrees that Lyell's letters shed no new light on extensions issue. Continental extensions: opposes their being hypothesised all over world.
Commonality of alpine plants damns both extension and migration.
Reports long preparation of work on how species and varieties differ. Agreement with Wallace's conclusions as reported in Annals and Magazine of Natural History and in his letter to CD of 10 0ct [1856]. On distinction between domestic varieties and those in "a state of nature".
On mating of jaguars and leopards, the breeding of poultry, pigeons, etc.
Requests help for his experimenting on means of distribution of organic beings on oceanic islands.
Believes species have arisen, like domestic varieties, with much extinction, and that there are no such things as independently created species. Explains why he believes species of the same genus generally have a common or continuous area; they are actual lineal descendants.
Discusses fertilisation in the bud and the insect pollination of papilionaceous flowers. His theory explains why, despite the risk of injury, cross-fertilisation is usual in the animal and vegetable kingdoms, even in hermaphrodites.
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Darwin concluded On the origin of species with the words: 'There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.' This was his first use of the word 'evolution', in any form, in print. He did not invent the term but with his mechanism of 'natural selection', supplemented by ideas about sexual selection, 'divergence' and inheritance, he did describe just how evolution - the continual development of new organisms - could take place.