What is one quote that shows the theme of dehumanization of natives (in book 2) and why does it show this theme?

There were no practical hints to interrupt the magic current of phrases, unless a kind of note at the foot on the last page, scrawled evidently much later, in an unsteady hand, may be regarded as the exposition of a method. It was very simple, and at the end of that moving appeal to every altruistic sentiment it blazed at you, luminous and terrifying, like a flash of lightning in a serene sky: ‘Exterminate all the brutes!’" Ch2