" ‘Take!’ said Abernethy, ‘why, take advice, to be sure.’ "

“But,” said the Prefect, a little discomposed, “I am perfectly willing to take advice, and to pay for it.  I would really give fifty thousand francs to any one who would aid me in the matter.”

“In that case,” replied Dupin, opening a drawer, and producing a check-book, “you may as well fill me up a check for the amount mentioned.  When you have signed it, I will hand you the letter.”

I was astounded.  The Prefect appeared absolutely thunder-stricken.  For some minutes he remained speechless and motionless, looking incredulously at my friend with open mouth, and eyes that seemed starting from their sockets; then, apparently recovering himself in some measure, he seized a pen, and after several pauses and vacant stares, finally filled up and signed a check for fifty thousand francs, and handed it across the table to Dupin.  The latter examined it carefully and deposited it in his pocket-book; then, unlocking an escritoire, took thence a letter and gave it to the Prefect.  This functionary grasped it in a perfect agony of joy, opened it with a trembling hand, cast a rapid glance at its contents, and then, scrambling and struggling to the door, rushed at length unceremoniously from the room and from the house, without having uttered a syllable since Dupin had requested him to fill up the check.

When he had gone, my friend entered into some explanations.

“The Parisian police,” he said, “are exceedingly able in their way.  They are persevering, ingenious, cunning, and thoroughly versed in the knowledge which their duties seem chiefly to demand.  Thus, when G—­ detailed to us his made of searching the premises at the Hotel D—­, I felt entire confidence in his having made a satisfactory investigation — so far as his labors extended.”

“So far as his labors extended?” said I.

“Yes,” said Dupin.  “The measures adopted were not only the best of their kind, but carried out to absolute perfection.  Had the letter been deposited within the range of their search, these fellows would, beyond a question, have found it.”

I merely laughed — but he seemed quite serious in all that he said.

“The measures, then,” he continued, “were good in their kind, and well executed; their defect lay in their being inapplicable to the case, and to the man.  A certain set of highly ingenious resources are, with the Prefect, a sort of Procrustean bed, to which he forcibly adapts his designs.  But he perpetually errs by being too deep or too shallow, for the matter in hand; and many a schoolboy is a better reasoner than he.  I knew one about eight years of age, whose success at guessing in the game of ‘even and odd’ attracted universal admiration.  This game is simple, and is played with marbles.  One player holds in his hand a number of these toys, and demands of another whether that number is even or odd.  If the guess is right,