Don't forget that.

Never forget, McKeever, that the friends of John Mark must be treated with gloves--always!" "Very good," replied McKeever, like a pupil memorizing in class.
"I'll see how far I can go with them," went on M.Fernand.He went straight to the telephone and rang John Mark.
"How far should I go with them ?" he asked, after he had explained that Smith had just come in.
"Is there someone with him ?" asked John Mark eagerly.
"A young chap about the same age--very brown." "That's the man I want!" "The man you want ?" "Fernand," said Mark, without explaining, "those youngsters have gone out there to make some money at your expense." M.Fernand growled.

"I wish you'd stop using me as a bank, Mark," he complained.

"Besides, it costs a good deal." "I pay you a tolerable interest, I believe," said John Mark coldly.
"Of course, of course! Well"-- this in a manner of great resignation--"how much shall I let them take away ?" "Bleed them both to death if you want.

Let them play on credit.