Interested that HM is studying structure of insects in relation to flowers.

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.

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

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

On HM’s Befruchtung der Blumen [1873].

Comments on Fritz Müller’s article on Hedychium.

Thanks HM for his review [of Forms of flowers, Kosmos 2 (1877–8): 286].

Thinks HM’s previous article was very important [Kosmos 2 (1877–8): 128–40]. CD will "heartily rejoice" if HM has explained the steps by which Rhamnus and Valeriana have been rendered dioecious.

Writing on vegetable physiology.

Nothing in CD’s life has ever interested him more than the fertilisation of such plants as Primula and Lythrum.

Has just heard that HM has been treated shamefully by his Government. What has happened?