“Humph!” grunted the doctor.

“Come, there’s no need for you to hold your tongue,” cried the professor petulantly. “Say something.”

“Very well, I’ll say something,” replied the doctor: “I don’t know.”

“Yes, you do. You know it’s impossible.”

“No,” said the doctor thoughtfully; “I know it would be very hard, but seeing what a stubborn, determined fellow Frank is, I should not be surprised if he succeeded.”

“Hurrah!” cried Frank. “There, Landon.”

“Bob ought to know better,” cried the professor. “It’s impossible—that’s impossible—the whole business is impossible. Can’t be done.”

“Well, I don’t know,” said the doctor, taking both hands to his beard and stroking and spreading it out over his breast, where it lay in crisp curls, glistening with many lights and giving him a very noble and venerable aspect. “I’m beginning to like that idea of going as a learned physician.”

“Oh, yes, that’s right enough,” said the professor. “There’s no imposition there. The Arabs would have nothing to find out, and their suspicions would be allayed at once. Then, too, you could humbug them grandly with a few of your modern doctors’ tools—one of those double-barrelled stethoscopes, for instance; or a clinical thermometer.”

“To be sure,” cried Frank. “Modern Magic—good medicine for the unbelieving savages. An electric battery, too; and look here, both of you: the Röntgen rays.”