K. G. Semper’s article ["On the relationship of the Vertebrata and Annelida", Ann. & Mag. Nat. Hist. 15 (1875): 94–5] is ill-natured. Misinterprets facts already discovered by F. M. Balfour.

Has been working on Amphioxus. Puts his theory of vertebrate skulls on firm footing at last.

Entirely sympathises with CD about Mivart’s attack on George. THH has had a letter from Mivart in which he pleads guilty, but THH has decided there is no patching the matter up. Advises against doing anything unless Mivart takes initiative.

Agrees with CD on vivisection. Will communicate with Burdon Sanderson and see what can be done.

Mivart’s wriggle.

Writes on behalf of Royal Society Polar Committee for suggestions concerning instructions to naturalists on new expedition.

Sends his thoughts on [vivisection] petition. Thinks they might make petition more talked about. Leaves it to J. Paget, Burdon Sanderson, and CD to deal with.

Lord Cardwell thinks it unlikely that Parliament will take any action on a vivisection bill this session. Playfair should be consulted.

E. F. W. Pflüger’s important memoir on how carbonic acid is produced by living matter and his speculation about origin of living matter [see 9931].

Lyon Playfair’s bill [on vivisection] is unacceptable to all teachers of physiology. It prohibits dissections for demonstrations to students. He will have to repudiate it. Asks CD’s advice.

Thanks for THH’s essay on species [article for an American encyclopedia].

Will probably never again write on large and general subjects; will keep to easier specific ones such as insectivorous and climbing plants.

Astonished and disgusted at Klein’s evidence. No doubt there will be severe and vicious legislation against physiology. Will give evidence before Commission.

Thanks for Elementary biology [1875]. Wishes he had had a course like it.

Is coming to London. Will call on THH.

Deeply grateful for THH’s tribute to him at conferring of LL.D. at Cambridge.

Thanks for evolution article; would like to know what made Lamarck "change his front" so completely.

CD’s election to Botany Section of French Academy amuses him, because he "doesn’t know the characters of a single natural order!".

About Anthony Rich, who has decided to leave his fortune to CD [and later also to make a bequest to THH]. CD’s account of what he wrote to Rich.

Has read Hume with great pleasure, but found parts very stiff reading.

George Darwin has visited Anthony Rich.

Thanks for Haeckel’s Freedom in science and teaching [1879], with preface by THH.

Enjoyed rap on knuckles THH gives Rudolf Virchow.

Asks THH to advise him about a response to Samuel Butler’s attack accusing CD of dishonesty. Quotes the advice of others but will do what THH advises.

Greatly relieved by THH’s letter [advising against a reply to Samuel Butler].

Is in town and will call on Sunday morning.