as
left a broad scar right across my forehead?--so I gave it up.

"I was in the French police for a time, and used to watch some of the
lower hells. I was nearly killed there once or twice, and at last I
came back here. My French chief gave me a letter to the chief, and I was
taken on at once, for, talking as I do half a dozen languages, and being
acquainted with most of the swell mobsmen of Paris, I was just the man
who happened to be wanted here at the time. Since I came over I have
done a good deal in the way of breaking up hells where sailors and
others are plundered. But, you see, I cannot be used for the higher
class of work; my nose has been broken, and I have half a dozen scars on
my face. I hate the sight of cards now. I have seen so much of the ruin
they do, and have, I am sorry to say, taken a hand so often in doing it,
that save showing someone who would use the knowledge in the right way
how the tricks are done, nothing would persuade me to touch them again.
However, as a protection, the knowledge is as useful as it is dangerous
when used the other way. It would take you ten years to learn to do
these tricks yourself so well as to defy detection; but in a very short
time, by learning where to keep your eyes, you would get to detect
almost any of them.

"You see, there are three methods of cheating: the first by hidden
cards, the second by marked cards, the third simply by sleight of hand,
this being generally used in connection with marked cards. These tricks
require great skill and extreme delicacy of touch, for the marks,
which are generally at the edge of the cards, are so slight as to be
altogether imperceptible save to a trained hand. There are also marks on
the back of the cards; these are done in the printing, and are so slight
that, unless attention were attracted to them, no one would dream of
their existence."

In the course of a week's practice Mark learned where to look for
cheating; he could not indeed follow the fingers of his instructor, for
even when he knew what was going to be done, the movements were so rapid
that his eye could not follow them, and in nine cases out of ten he
was unable to say whether the coup had been accomplished or not; but
he could see that there was a slight movement of the fingers that could
only mean that something was being done.

"It would be a good thing," he said one day, "if every young fellow
before going out into the world were to have a course of such