And, following the course of an evening's play, Fernand knew the exact moment at which a man had had enough.

It was never twice the same for the same man.

A rich fellow, who lost twenty thousand one day and laughed at it, might groan and curse if he lost twenty hundred a week later.
It was Fernand's desire to keep those groans and curses from being heard in his gaming house.

He extracted wallets painlessly, so to speak.
He was never crooked; and yet he would not have a dealer in his employ unless the fellow knew every good trick of running up the deck.

The reason was that, while Fernand never cheated in order to take money away from his customers, he very, very frequently had his men cheat in order to give money away.
This sounds like a mad procedure for the proprietor of a gaming house, but there were profound reasons beneath it.