Thanks LJ for his book [Observations in meteorology (1858)].

CD has been working on his species book [Natural selection].

Has become dreadfully heterodox on immutability of species.

His work on pigeons: variation under domestication throws the greatest light on variation in a state of nature.

Asks LJ to lend him a copy of his paper ["Variation of species", Rep. BAAS 26 (1856): 101–5] and any notes or references he has. Although CD has a large accumulation of facts, it is impossible to see and consider too many.

His health is poor.

[Copy of some rough notes.] References about species. Variations within species.

Thanks LJ for his MS [of "Variation of species", Rep. BAAS 26 (1856): 101–5].

Will read it at his hydropathic establishment [Moor Park], where he is going for a rest.

Returns MS [of "Variation of species"]; several facts were new to him, especially interested in wagtails.

Wishes he could swallow Florent Prévost on sparrows ["Du régime alimentaire des oiseaux", C. R. Hebd. Acad. Sci. 46 (1858): 136–8].

LJ’s facts seem to bear out CD’s conclusion that secondary sexual characters were most variable of all.

Explains how he intends to deal with variation, and general facts in natural history in the light of species theory. Can only afford one chapter on variation in nature. It seems more important to make out variation in domestic animals.

Asks for facts on birds’ nests for his chapter on instincts.

Invites criticisms of his book [Origin] which is "only an abstract & very much condensed". Knows LJ will not agree with the lengths to which CD goes. It took long years to convert CD, but he cannot persuade himself "that a theory which explains … several large classes of facts, can be wholly wrong".

Hopes to publish his full MS if he ever gets strong enough.