Oswald Heer [in Die Urwelt der Schweiz (1866)] agrees with CD that Swiss ants (Formica sanguinea) capture more slaves than do British ants. Does this contradict selection, since the British ants are exposed to harder conditions and a poorer fauna?

Writes on slave-making ants; cannot explain why fewer slaves are caught in England than in Switzerland.

Calls for more study of behaviour and less of classification to determine whether descent theory can bear the weight not [only] of reasoning but of fact. Hopes CD’s intended book [Variation] will help.