C. Nägeli’s long letter on his four years of work on Hieracium appears to be valuable. Nägeli wants a set of British forms in exchange for German ones.

Sends note on a new genus of Umbelliferae (Drusa) in Canaries; speculates on origin.

JVC is willing to translate [Variation], especially because of his conviction that progress of biology depends on proving CD’s theory.

Ernst Haeckel’s book [Generelle Morphologie (1866)] will do mischief because EH is so immoderate. Suggests CD tell EH that he has done him a bad service. CD is the only one to whom EH would listen.

Reports on an experiment in crossing potato varieties.