It was great fun writing a book.... It built an impalpable crystal sphere around one of interests and ideas. In a sense one felt like a goldfish in a bowl; but in this case the goldfish made his own bowl. This came along everywhere with me. It never got knocked about in travelling, and there was never a moment when agreeable occupation was lacking. Either the glass had to be polished, or the structure extended or contracted, or the walls required strengthening.

Don't join the book burners. Don't think you are going to conceal faults by concealing evidence that they ever existed.

Man in his arrogance thinks himself a great work, worthy of the interposition of a deity. More humble, and I believe truer, to consider him created from animals.

I do not believe, as we shall presently see, that all our dogs have descended from any one wild species; but, in the case of some other domestic races, there is presumptive, or even strong, evidence in favour of this view.

Embryology will reveal to us the structure, in some degree obscured, of the prototypes of each great class.

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.