Summary

Debates aberrant species, e.g., Ornithorhynchus and Echidna, with JDH. CD argues they are result of extinction having removed intermediate links to allied forms.

Studying effects of disuse in wings of tame and wild ducks.

Tabulations showing that number of species in a genus is not correlated with number of genera in an order.

Summary

Bentham’s list of aberrant genera: CD’s worry that he eliminated large genera a priori is half right. He eliminated those large, anomalous genera that virtually constitute natural orders. JDH criticises CD’s tabulations of aberrants.

Difficulty of distinguishing affinity and analogy in plants.

Summary

Fossil leaves from Disko Island.

JDH to begin working out the botanical geography of the polar sea.

Has not forgotten CD’s request on aberrant species.

Has taken a house on Richmond Hill.

Summary

JDH on "highness" of Coniferae: they are genuine Dicotyledons, not a link to cryptogams; that is a geologists’ fallacy. Thus they are highest plants in Carboniferous.

Does not agree with CD’s "elastic" species theory. Long correspondence with Lyell on this.

Summary

Is Bentham’s list of aberrant genera biased by exclusion of genera with many species?

JDH’s belief that Aquilegia varieties are one species is consistent with their great interfertility.

Summary

Can AH give information about D. A. Godron, "De l’espèce et des races" [Mem. Soc. Sci. Lett. & Arts Nancy (1847): 182, 239–88]? CD unable to locate reference.

Summary

Important issue at stake with new flora calculations: evidence that species are only strongly marked varieties. Planning large-scale survey.

Summary

Hugh Falconer’s misbehaviour.

Waiting out rains at Brian Hodgson’s.

Will make botanical transverse section of Himalayas from plains to snow.

Arrangements to pass Sikkim Rajah’s territory.

No evidence of glacial or diluvial action in sub-Himalayan mountains. No evidence of detrital coal formation.

Hodgson’s replies to CD on introduced species and hybrids.

Summary

Thanks JDH for dedication of Himalayan journals. CD praises the work and suggests stylistic revisions.

Lyell’s remarks on lava beds in letter from Madeira are not original – they refer exclusively to Élie de Beaumont’s data.

Summary

Falconer’s misbehaviour.

Geology of Khashia [Khasi] mountains. Speculations on mountain building and origin of Himalayas.

Summary

Spoke too harshly about CD’s involvement in nomenclatural reform.

JDH used to think CD "too prone to theoretical considerations about species", hence was pleased CD took up a difficult group like barnacles. CD’s theories have progressed but JDH not converted. Sikkim has not cleared up his doubts about CD’s doctrines.

Argument with Falconer.

Summary

List of most anomalous Leguminosae [from George Bentham].

Summary

JDH’s "grand speech" on receiving the Royal Medal.

Summary

CD welcomes the prospect of the Philosophical Club of the Royal Society as means for seeing old acquaintances and making new ones. Will try to go up to London regularly.

Admits that the warning from JDH and Asa Gray (that more harm than good will come from combat over the species issue) makes him feel "deuced uncomfortable".

Reflects upon the complexity of Agassiz; how singular that a man of his eminence and immense knowledge "should write such wonderful stuff & bosh".

Summary

JDH and F. W. Binney identify Calamites specimens as pith casts. They are cryptogams related to, but higher than, Lycopodiaceae and contradict progression.

Insects found in coal.

Lyell says Stonesfield slate marsupials are actually placentals.

JDH reading Alexander Braun on individuality ["Das Individuum der Pflanze in seinem Verhältniss zur Species", Abh. K. Akad. Wiss. Berlin (Phys. Kl.) (1853): 19–122].

Summary

Calculating small number of species in aberrant genera of insects and plants.

Joachim Barrande’s "Colonies", Élie de Beaumont’s "lines of Elevation", Forbes’s "Polarity" make CD despair, as these theories lead to conclusions opposite to CD’s from the same classes of facts.

Summary

JDH’s contempt for R. I. Murchison.

There is a Cyperus species and a Pteris species endemic to hot volcanoes of Ischia. Why are there no other migrators?

Summary

Birth of JDH’s second child.

Asks CD’s view of "highness" and "lowness" in animals. Gives his own for plants; extent of deviation from type, e.g., floral parts deviating from leaf.

Reading B. C. Brodie’s Psychological inquiries [1854].

Summary

JDH summarises letter from Humboldt.

JDH answers CD’s questions on glacial action in Himalayas.

Summary

Plans to come to Down on Saturday.

Returned Adam Bede two years ago.

Wishes CD would return Tylor’s Early history of mankind

and his own Himalayan journal with his notes, "both of which I have lent, i.e., lost".

Lyell well and full of "Insular" difficulties which he will propound.