““Man and the rat are utterly destructive. All that nature offers is taken for their own purposes, plant or beast. Gradually these two have spread across the earth, keeping pace with each other and unable to destroy each other, though continually hostile. They have wandered from East to West, driven by their physical needs, and—unlike any other species of living things—have made war upon their own kind. The gradual, relentless, progressive extermination of the black rat by the brown has no parallel in nature so close as that of the similar extermination of one race of man by another. Did the Danes conquer England; or the Normans the Saxon-Danes; or the Normans the Sicillian-Mohammedans; or the Moors the Latin-Iberians; or the Franks the Moors; or the Spanish the Aztecs and the Incas; or the Europeans in general the aborigines of the world by qualities other than those by which Mus decumanus has driven out Mus rattus? In both species, the battle has been pitilessly to the strong. And the strong have been pitiless. The physically weak have been driven before the strong—annihilated, or constrained to the slavery of doing without the bounties which were provided for all equally. Isolated colonies of black rats survive, as weaker nations survive until the stronger ones desire the little they still possess. The rat has an excuse. As far as we know, it does not appear to have developed a soul, or that intangible quality of justice, mercy, and reason that psychic evolution has bestowed upon man. We must not expect too much.””