Discusses Louis Agassiz’s theory of the glaciation of Brazil.

Will be pleased to sign FWF’s certificate for the Royal Society if he can send it to CD, who does not have the strength to go to London.

Asks CD whether he knows of a medicine to check vomiting – for a friend dying from starvation as a result.

Duke of Somerset is looking for two naturalists for survey ship to Korea and Strait of Magellan.

Looks forward to reading Variation.

Explains how two or more female forms occur in one species through selection. The physiological problem remains of how each produces offspring like the other without intermediates. Is not CD’s case of varieties that will not blend the physiological test of a species needed for "complete proof of the origin of species"?

"Travels" postponed.

Thanks CD for supporting his application to the Royal Society.

Cannot give advice on the artistic merits of her photographs as he is not qualified, but offers suggestions and praise on the mechanics of the art.

Memorandum of a meeting of the Natural History & Antiquarian Society held in Dumfries on Tuesday 6 February 1866.

Requests repayment of loan as FR promised last spring.

ARW’s simple explanation of dimorphic forms is satisfactory.

On "non-blending" of certain varieties, CD thinks ARW has not understood him. He does not refer to fertility. He crossed two differently coloured varieties of peas and "got both varieties perfect, but none intermediate". Something like this must occur in ARW’s butterflies.

Discussion of Mrs Agassiz’s letter [to Mary Lyell, forwarded to CD] regarding S. American glacial action,

with comments on Bunbury’s letter on temperate plants.

Refers to opinions of Agassiz, David Forbes, Hooker, and CD on glacial period and glaciers.

Wishes he had published a long chapter on glacial period [Natural selection, pp. 535–66] written ten years ago.

Tells of death of his sister, Catherine, and other family matters.

Is compelled to ask for postponement of payment of principal. His invention is gaining ground. Will pay interest until payment is made.

Sending a pamphlet on the quality of refracted light. Hopes JH will communicate it to the R.S.L.

Sends the numbers [of periodicals?] CD wished to see, and a list of other journals in which his papers have appeared.

Asks botanical readers to inform him "whether in those monoecious or dioecious plants, in which the flowers are widely different, it has ever been observed that half the flower, or only a segment of it, has been of one sex and the other half or segment of the opposite sex, in the same manner as so frequently occurs with insects?"

Sends a diet for CD’s flatulence.

Thanks CD for his kind expressions [of sympathy] and for his consideration. Encloses cheque for £5 interest.

Orders Richard Owen’s Anatomy of vertebrates [1866–8],

subscribes to Annals and Magazine of Natural History,

and orders three back numbers of Medical Times and Gazette.

Discusses beauty of birds and butterflies.

Responds to JH's criticisms of his binocular telescope plans.

Thanks CD for Journal of researches.

Insect genus Elater is an exception to the rule that all luminous organs give out a green light.

Gives some observations on climbing plants at Itajahy.

His study of orchids has convinced him of the value of CD’s book.