“skinny, yellow, toothless, bald-headed, rat-eyed”

Mark Twain via Andrew Delbanco in the NYRB:

A reviewer who panned The Gilded Age is a “reptile.” A publisher who refused Twain’s terms is an “animal,” and, more particularly, a “skinny, yellow, toothless, bald-headed, rat-eyed” animal.

Well, probably not toothless, but "absence of evidence..."