f of her apartment house.

"But we don't worry about her any more. People with acute acrophobia
are in no condition to pull stunts like that."

"What will you do to this Hammerlock Smith, then?" His Grace asked.

"Actually, he's one of the simpler cases. A large percentage of our
zanies lose control when they're under the influence of alcohol or
drugs. Alcohol is by far the more common. Under the influence, they do
things they would never do when sober.

"As long as they remain sober, they have control. But, give them a few
drinks and the control slips and then vanishes completely. One of our
others was a little like Manny the Moog; he drove like a madman--which
he was when he was drunk. Sober, he was as careful and cautious a
driver as you'd want--a perfectly reliable citizen. But, after losing
his license and the right to own a car, he'd still get drunk and steal
cars.

"He has his license back now, but we know we can trust him with it. He
will never be able to take another drink.

"Smith is of that type. So, apparently, is Nestor. When we get through
with Smith, he'll be sober, and he'll stay that way to his grave."

* * * * *

"Astounding." The Duke looked at me again. "I can see the results, of
course. I'm going to see that some sort of similar program is started
in England, even if I have to stand up in the House of Lords to do it.
But, I still don't understand how it can be done so rapidly--a matter
of hours. What is the technique used?"

"It all depends on the therapist," I said. "Brownlee is one of the
best, but there are others who are almost as good. Some of the
officers have started calling them _hexperts_ because, in effect,
that's exactly what they do--put a hex on the patient."

"A _geas_, in other words."

I'd never heard the word before. "A what?"

"A _geas_. A magical spell that causes a person to do or to refrain
from doing some act, whether he will or no. He has no choice, once the
_geas_ has been put on him."

"That's it exactly."

"But, man, it isn't magic we're discussing, is it?"

"I don't know," I admitted frankly. "You tell me. Was it magic this
morning when both you and I had a hunch that little Shirley was _not_
in the park, in spite of the way it looked? Was it magic when we
eliminated, without even searching, every spot but the place where she
actually was?"

"Well, no, I shouldn't say so. I think every good policeman gets
hunches like tha