"Why, dear master, everything that took place last night! Is it true that you have summoned here all Thomery's guests?... Have you obtained such perfect reprints that, in your hasty examination, you can be certain of identifying them with those of the persons who will pass through your office to undergo the test?"

Bertillon smiled:

"Oh, my dear fellow, you are of those who do not put much faith in the results of my tests for police purposes! That, let me tell you, is because you are not acquainted with our procedure. The impressions I obtained are distinct—precise as can be; if an arrest is made before long it will be made on sure grounds."

Fandor bowed:

"I accept your statement, dear master!... But, do be kind enough to tell me what happened after my departure?"

"Oh, nothing very extraordinary.... Of course you know about the affair—how the Princess Sonia Danidoff was discovered?..."

"What I know is that Thomery found one of his guests, Princess Sonia Danidoff, in a dead faint in a small drawing-room; that Dr. Du Marvier declared she had been rendered unconscious; that the theft of a pearl necklace worn by the victim had been the motive of this criminal attempt; that Monsieur Havard, called in at once, first made sure that no one had left the house, and then had everyone on the premises searched ... and that is really all I know about it!"

"Well, Havard did not find anything!"

"No one was caught with compromising jewels in their possession. The last guest gone, the house searched from top to bottom, not a single pearl had been found.... I arrived just when the investigations had terminated: at the moment when they were about to take the Princess home. She had regained consciousness by this time and declared she knew nothing except that she had fallen asleep after using a perfume sprayer. This has been seized and chloroform has been found in it; but no one seems to know who filled the sprayer with this stupefying perfume."

"Did Monsieur Havard send for you?"