now. You say his
nail marks show?"

Tignol shrugged his shoulders. "They show as little scratches, but not
enough for any funny business with a microscope."

"Little scratches are all I want," said the other, snapping his fingers
excitedly. "It's simply a question which side of his throat bears the thumb
mark. We know the murderer is a left-handed man, and, being suddenly
attacked, he certainly used the full strength of his left hand in the first
desperate clutch. He was facing the man as he took him by the throat, so,
if he used his left hand, the thumb mark must be on the left side of the
photographer's throat, whereas if a right-handed man had done it, the thumb
mark would be on the right side. Stand up here and take me by the throat.
That's it! Now with your left hand! Don't you see?"

"Yes," said Tignol, making the experiment, "I see."

"Now bring the man in here, wake him, tell him--tell him anything you like.
I must know this."

"I'll get him in," said the commissary. "Come," and he followed Tignol into
the hall.

A few moments later they returned with a thin, sleepy little person wrapped
in a red dressing gown. It was the shrimp.

"There!" exclaimed Papa Tignol with a gesture of satisfaction.

The photographer, under the spell of Pougeot's authority, stood meekly for
inspection, while Coquenil, holding a candle close, studied the marks on
his face. There, plainly marked _on the left side of the throat_ was a
single imprint, the curving red mark where a thumb nail had closed hard
against the jugular vein (this man knew the deadly pressure points), while
on the right side of the photographer's face were prints of the fingers.

"He used his left hand, all right," said Coquenil, "and, _sapristi_, he had
sharp nails!"

"_Parbleu!_" mumbled the shrimp.

"Here over the cheek bone is the mark of his first finger. And here, in
front of the ear, is his second finger, and here is his third finger, just
behind the ear, and here, way down on the neck, is his little finger. Lord
of heaven, what a reach! Let's see if I can put my fingers on these marks.
There's the thumb, there's the first finger--stand still, I won't hurt you!
There's the second finger, and the third, and--look at that, see that mark
of the little finger nail. I've got long fingers myself, but I can't come
within an inch of it. You try."

[Illustration: "'Stand still, I won't hurt you.'"]

Patiently the photographer stood still while the commis