Blushing is the most peculiar and most human of all expressions.

Worms have played a more important part in the history of the world than humans would at first suppose.

The great variability of all the external differences between the races of man, likewise indicates that they cannot be of much importance; for if important, they would long ago have been either fixed and preserved, or eliminated.

Why is thought being a secretion of brain, more wonderful than gravity a property of matter? It is our arrogance, our admiration of ourselves.

Species of the same genus would occasionally exhibit reversions to lost ancestral characters.

Did man, after his first inroad into South America, destroy, as has been suggested, the unwieldy Megatherium and the other Edentata?