Is preparing a work on fertilisation of flowers, and wants to add a list of works containing observations on cross-fertilisation of plants. Asks CD for any references he may have.

Comments on HM’s paper ["Anwendung der Darwin’schen Lehre auf Bienen", Verh. Naturhist. Ver. preuss. Rheinland 29 (1872): 1–96];

sexual selection in bees.

Encloses account on habits of Bombus.

Thanks CD for MS on the routes of male bees.

His "Fertilisation of flowers" is complete [Die Befruchtung der Blumen (1873)].

Sends his book [Die Befruchtung der Blumen (1873)]. Hopes CD will publish an opinion of it.

Comments on HM’s book [Die Befruchtung der Blumen (1873)]. Particularly glad to read historical sketch and discussion of work of C. K. Sprengel.

Praises Expression.

Reports on Fritz Müller’s observations of cross- and self-fertilisation. HM will cultivate the two forms [i.e., mainly self-fertilised and mainly cross-fertilised] in the way CD has described.

He continues his observation of wild flowers. Encloses drawing of Viola tricolor with notes on its self-fertility.

Thanks for CD’s praise of his book [see 8901].

Poa annua shows putative evidence of nectar secretion in grasses. He will continue observations as CD requests.

Further comments on HM’s [Befruchtung der Blumen (1873)].

Reports on insects fertilising Viola tricolor and on the fertilisation of the two wild forms [see Cross and self-fertilisation, p. 124 n., 125].

Sends a note on R. Caspary’s observations of Corydalis self-fertilisation [see Cross and self-fertilisation, p. 331].

Has begun his experiments on the self- and cross-fertilised flowers.

Fritz Müller is now working on the Brazilian honey-bees (Melipona and Trigona).

HM thanks CD for fertilisation references.

Feels CD’s and Fritz Müller’s judgments on his "Anwendung" essay [see 8313] are of highest value. Mentions some of FM’s comments.

Looks forward to second English edition of Descent.