Discusses a proposed expedition to Australia. Urges collecting and investigating productions of isolated islands. Recommends dredging the sea-bottom.

Mentions keeping Helix pomatia alive in sea-water.

CD returns a letter from Wollaston.

Although opposed to the Forbesian doctrine [of continental extension] as a general rule, CD would have no objection to its being proved in some cases. Does not think Wollaston has proved it; nor can anyone until more is known about the means of distribution of insects – but the identity of the two faunas is certainly interesting.

His health is very poor and his "everlasting species-Book" quite overwhelms him with work. It is beyond his powers, but he hopes to live to finish it.