The detection of the murderers of M. Delahache, a misanthrope who lived with a paralysed mother and one old servant in a ruined abbey at La Gloire Dieu, near Troyes, was much facilitated by the carelessness with which the criminals neglected to carry off a note-book from the safe. After they had slain their three victims, they forced the safe and carried off a large quantity of securities payable to bearer, for M. Delahache was a saving, well-to-do person. They took all the gold and banknotes, but they left the title-deeds of the property and his memorandum book, in which the late owner had recorded in shorthand, illegible by the thieves, the numbers and description of the stock he held, mostly in Russian and English securities. By means of these indications it was possible to trace the stolen papers and secure the thieves, who still possessed them, together with the pocket-book itself and a number of other valuables that had belonged to M. Delahache. Criminals continually "give themselves away" by their own carelessness, their stupid, incautious behaviour. It is almost an axiom in detection to watch the scene of a murder for the visit of the criminal, who seems almost irresistibly drawn thither. The same impulse attracts the French murderer to the Morgue, where his victim lies in full public view. This is so thoroughly understood in Paris that the police keep officers in plain clothes among the crowd which is always filing past the plate-glass windows separating the public from the marble slopes on which the bodies are exposed. An Indian criminal's steps generally lead him homeward to his own village, on which the Indian police set a close watch when a man is much wanted. Numerous cases might be quoted in which offenders disclose their crime by ill-advised ostentation: the reckless display of much cash by those who were, seemingly, poverty-stricken just before; self-indulgent extravagance, throwing money about wastefully, not seldom parading in the very clothes of their victims. A curious instance of the neglect of common precaution was that of Wainwright, the murderer of Harriet Lane, who left the _corpus delicti_, the damning proof of his guilt, to the prying curiosity of an outsider, while he went off in search of a cab.