Note 18 — Chapter III · THE GRADES OF THE FACTORS OF EVOLUTION AND THE ORDER OF THEIR APPEARANCE.

Mr. Wallace has recently, in his work on “Darwinism,” taken strong ground against this Darwinian factor. He thinks, for example, that sexual vigor is the cause of both the splendor of color and the pertinacity which secures the female. We see little difference in this way of putting it. Our object, however, is not to argue the question of what are true factors, but simply to give the most accepted, and, as it seems to us, also the most probable view.