A few words on the manner in which the work has been compiled are due to the reader. In order to complete my own private information, specially with reference to old cant, I have drawn as freely as seemed to me legitimate on works of a similar character--Michel’s, Delvau’s, Rigaud’s, Lorédan Larchey’s excellent _Dictionnaire Historique d’Argot_, Vilatte’s _Parisismen_, a very complete work on French _argot_ rendered into German. But by far the most important portion of my collection has been gathered from Vidocq’s productions, Balzac’s works, _The Memoirs of Monsieur Claude_, formerly superintendent of the detective department in Paris, and from other works to be mentioned hereafter. To an inspector of the detective force in Paris, Monsieur Lagaillarde, I am indebted for many of the terms of the phraseology used by the worthies with whom his functions have brought him in contact.
Again, newspapers of both countries have also brought in their contingent, but the most interesting sources of information, as being the most original, have been workpeople, soldiers, pickpockets, and other malefactors having done their “time,” or likely to be “wanted” at a short notice. The members of the light-fingered gentry were not easily to be got at, as their natural suspicions precluded their realizing at once my object, and it required some diplomacy and pains to succeed in enlisting their services. In one particular instance I was deprived of my informants in a rather summary manner. Two brothers, members of a family which strongly reminded one of E. Sue’s Martials, inasmuch as the father had mounted the scaffold, the mother was in prison, and other members had met with similar accidents, had volunteered to become my collaborators, and were willing to furnish information the more valuable, it seemed to me, as coming from such distinguished individuals. Unfortunately for the _Dictionary_ the brothers were apprehended when coming to my rendez-vous, and are now, I believe, far on their way to the penal settlement of New Caledonia.
I have to thank numerous correspondents, French and English officers, journalists, and artists, for coming to my assistance and furnishing me with valuable information. My best thanks are due also to M. Godefroy Durand for his admirable etching.