They _may_ have grown into, or something like, human beings.

Lady Arabella March is of snake nature.
She has committed crimes to our knowledge.

She retains something of the vast strength of her primal being--can see in the dark--has the eyes of a snake.

She used the nigger, and then dragged him through the snake's hole down to the swamp; she is intent on evil, and hates some one we love.

Result.