The old doctor felt my pulse, evidently thinking of something else the while. "Good, good for there," he mumbled, and then with a certain eagerness asked me whether I would let him measure my head. Rather surprised, I said Yes, when he produced a thing like calipers and got the dimensions back and front and every way, taking notes carefully.

     He was an unshaven little man in a threadbare coat like a gaberdine, with his feet in slippers, and I thought him a harmless fool.

     "I always ask leave, in the interests of science, to measure the crania of those going out there," he said.

     "And when they come back, too?" I asked.

     "Oh, I never see them," he remarked; "and, moreover, the changes take place inside, you know." He smiled, as if at some quiet joke. "So you are going out there. Famous. Interesting, too."

     He gave me a searching glance, and made another note. "Ever any madness in your family?" he asked, in a matter-of-fact tone.

     I felt very annoyed. "Is that question in the interests of science, too?"