Another pre-minstrelsy equine conformation reference:

“Byron, you know, said the hand was the true test of blood. Why did he not include the eye, the ear, the mouth, the nostril? Who ever saw the thoroughbred mare, or horse, with the hog eye – sole-leather ear – African mouth, and chunk-bottle nose?”
[Spirit of the Times, NY, 8 April 1837, p.60]