Does not remember his criticisms of CD’s theory. Can CD locate them in book?

Criticises analogy between knowledge of electricity and knowledge of origin of life.

Explains A. E. Brehm’s concept of subspecies. Discusses subspecies of Certhia.

Answers HGB’s criticism of Origin.

Explains HGB’s case of differences in rats by adaptation.

CD’s view explains homological and embryological resemblances of each type.

Does not believe all development is at same rate. Cites Australian forms.

Does not see force of objection that origin of life must be explained.

Asks if C. L. Brehm’s subspecies of birds are really characteristic of regions of Germany.