A woman passenger in a horse-drawn cab has offered the driver a large tip if he can deliver her to her destination in a hurry. However, she is horrified at the cruel whipping the driver is giving the horse to make him go faster.
"My good man, is there no other way you could urge the horse along?" she asks.
"Yessum," the cab driver cheerfully replies, "but, I've got to save his balls for the hill!"