ective--if you had a little more method--if you didn't follow your
instincts and that bump on your forehead. As I have already several
times observed, Monsieur Rouletabille, you reason too much; you do not
allow yourself to be guided by what you have seen. What do you say to
the handkerchief full of blood, and the red mark of the hand on the
wall? You have seen the stain on the wall, but I have only seen the
handkerchief."

"Bah!" cried Rouletabille, "the murderer was wounded in the hand by
Mademoiselle Stangerson's revolver!"

"Ah!--a simply instinctive observation! Take care!--You are becoming too
strictly logical, Monsieur Rouletabille; logic will upset you if you
use it indiscriminately. You are right, when you say that Mademoiselle
Stangerson fired her revolver, but you are wrong when you say that she
wounded the murderer in the hand."

"I am sure of it," cried Rouletabille.

Fred, imperturbable, interrupted him:

"Defective observation--defective observation!--the examination of the
handkerchief, the numberless little round scarlet stains, the impression
of drops which I found in the tracks of the footprints, at the moment
when they were made on the floor, prove to me that the murderer was not
wounded at all. Monsieur Rouletabille, the murderer bled at the nose!"

The great Fred spoke quite seriously. However, I could not refrain from
uttering an exclamation.

The reporter looked gravely at Fred, who looked gravely at him. And Fred
immediately concluded:

"The man allowed the blood to flow into his hand and handkerchief, and
dried his hand on the wall. The fact is highly important," he added,
"because there is no need of his being wounded in the hand for him to be
the murderer."

Rouletabille seemed to be thinking deeply. After a moment he said:

"There is something--a something, Monsieur Frederic Larsan, much graver
than the misuse of logic the disposition of mind in some detectives
which makes them, in perfect good faith, twist logic to the necessities
of their preconceived ideas. You, already, have your idea about the
murderer, Monsieur Fred. Don't deny it; and your theory demands that the
murderer should not have been wounded in the hand, otherwise it comes
to nothing. And you have searched, and have found something else. It's
dangerous, very dangerous, Monsieur Fred, to go from a preconceived idea
to find the proofs to fit it. That method may lead you far astray Beware
of judicial error, Monsieur