“The people who are running those places in the fifties are making barrels of money,” summarized Carton quickly.  “No one ever interferes with them, either.  I know from reliable sources, too, that the police are ‘getting theirs.’  But although I know it I can’t prove it; I can’t even tell who is getting it.  But once a week a collector for the police calls around in that district and shakes them all down.  By Jove, to-day is the day.  The trouble with it all is that they have made the thing so underground that no one but the principals know anything about it—­not even the agents.  I guess you are right about the detectaphone.”

“To-day’s the day, is it?” mused Craig.

“So I understand.”

“I think I can get them with a new machine they never dreamed of,” exclaimed Kennedy, who had been turning something over in his mind.

He reached for the telephone and called the Montmartre.

“Julius, please,” he said when they answered; then, placing his hand over the transmitter, he turned to Clare.  “That was your friend the Titian, Miss Kendall.”

“No friend of mine if she happens to remember seeing me in Dr. Harris’s office the other day.  Still, I doubt if she would.”

“Hello—­Julius?  Good morning.  How about a private dining-room for three, Julius?”

We could not hear the reply, but Craig added quickly, “I thought there were two?”

Evidently the answer was in the affirmative, for Craig asked next, “Well, can’t we have the small one?”

He hung up the receiver with a satisfied smile after closing with “That’s the way to talk.  Thank you, Julius.  Good-bye.”

“What was the difficulty?” I asked.

“Why, I thought I’d take a chance—­and it took.  Now figure it out for yourself.  Carton says it’s dough day, so to speak, up there.  What is more natural than that the money for all those places leased to various people should be passed over in a place that is public and yet is not public?  For instance, there is the Montmartre itself.  Now think it out.  Where would that be done in the Montmartre?  Why, in one of the private dining-rooms, of course.”

“That seems reasonable,” agreed Carton.

“That was the way I doped it,” pursued Craig.  “I thought I’d confirm it if I could.  You remember they told us to call up always if I wanted a private dining-room and it would be reserved for me.  So it was the most natural thing in the world for me to call up.  If they had said yes, I should have been disappointed.  But they said no, and straightway I wanted one of those rooms the worst way.  One seems to be engaged—­the large one.  He said nothing about the other, so I asked him.  Since I knew about it, he could hardly say no.  Well, I have engaged it for lunch—­an early luncheon, too.”

“It sounds all right, as though you were on the right trail,” remarked Carton.  “But, remember, only the best sort of evidence will go against those people.  They can afford to hire the best lawyers that money can retain.  And be careful not to let them get anything on you, for they are fearful liars, and they’ll go the limit to discredit you.”