Is currently at work on the development in birds of organs of flight according to CD’s principles; asks permission to quote CD in stating the theory.

Urges CD to republish his works in a collected edition, to make them more readily available to Germans.

CD has omitted in all his works one of the most interesting causes of variation, domestic or wild – i.e., frightening of a pregnant animal; quotes case of eight-footed horse from a French translation of G. S. W. von Adler.