Criticises Duke of Argyll’s address [to the Royal Society of Edinburgh (1864)] and demurs on Argyll’s "new birth" theory.

Agrees with CL on beauty.

Enjoyed hearing of Princess Royal’s discussion [on Darwinism].

CD’s illness.

CL’s advice on chapter [of Variation] on dogs was excellent.

Species of lice and the animals they infest. Different kinds of dogs, fowls, and pigeons are infested by the same species of Pediculi [see Descent 1: 219].

John Scott has arrived in Calcutta and has been given an appointment by Thomas Anderson.

Thanks JEG for congratulations [on Copley Medal?].

Mentions JEG’s illness.

Pleased at receiving CD’s letter.

HWB informs him of favourable notice of the mimetic paper [in Wiegmann’s Arch. Naturgesch. 29 (1863) pt 2: 315–19].

He is pleased with his post [Asst. Sec. of Royal Geographical Society].

Returns [Andrew] Murray’s paper;

especially values HD’s note that the same species of lice infect the different varieties of fowl, pigeon, and dog. Further queries about the relationship of the same species of pediculi to different domestic varieties.

Commends ARW’s papers on parrots

and on the theory of geographical distribution [see 4750].

Wild pigs in Aru Islands must have been introduced and later ran wild. Does ARW have an opinion on the subject?

Orders that one of CD’s Porto Santo rabbits be killed and sent to him.

Asks whether ADB has got young from mating these with females of other breeds.

Sends papers with comments. Convinced that the Aru pig is a species peculiar to New Guinea fauna, not a domestic animal that ran wild.

Admires CD’s paper ["Three forms of Lythrum", Collected papers 2: 106–31].

Exchange of photographs.

Aru pigs present perplexing case, whether wild or domesticated.

Hugh Falconer’s death great loss to science.

His own health has been especially bad this last week.

Is glad MTM is going to experiment on Passiflora.

Is grieved to hear that John Scott has been inaccurate but cannot think he recorded, in his paper, experiments that he never made [see 4485].

"Read a letter from Mr Darwin expressing his regret that the state of his health would not permit of his writing an Introductory Chapter to the Translation of Gaertner’s work [Bastarderzeugung im Pflanzenreich (1849)]."

Falconer’s illness and suffering. His great ability and knowledge.

CD’s paper ["Climbing plants"] went extremely well [at Linnean Society]. M. T. Masters and Bentham commented.

He has finished MEW’s work on hybrid willows [Die Bastardbefruchtung im Planzenreich (1865)] and sends his thanks. The extreme frequency of hybrid willows is new to CD, and he finds the explanation of their numbers in certain locations ingenious.

Comments on the criticism of Gärtner’s view of reversion

and the differences between MEW and Naudin.

CD now has doubts regarding his own view that hybrids are sterile from not being perfectly accommodated to their conditions of life.

MTM heard part of the abstract of CD’s paper on climbing plants, read at the Linnean Society on 2 Feb. Offers CD his opinion and information on the subject, which he has studied for many years.

Requests all parts of Transactions due him.

Inquires about body of Porto Santo rabbit which has not arrived.

Falconer’s death haunts him. Personal annihilation not so horrifying to him as sun cooling some day and human race ending.

His health has been wretched.

Masters has written his agreement with CD’s "Climbing plants".

Sends a pamphlet and photograph to CD [missing];

announces a botanical congress at Erfurt at which CD’s theory will be discussed.