No doubt the popular conception of the detective has been derived from the flash literature in which the "Old Sleuths" have formed the pervading figure. Concerning them, a clever ex-member of that particular branch of the force recently said: "Now that I'm out of the business I don't mind telling you what you perhaps already know--that the usual stories of detective work are the veriest bosh. There is not one officer in ten thousand, for instance, who ever disguises himself for any work he may be bent upon. The successful detective is the man who has the largest and most accurate knowledge of a particular class of criminals. For instance, in a counterfeiting case there are one or two United States officers who will look at a bill, and after a scrutiny will say, 'Now, let's see; there are three men in the country who are capable of such work as this. Bad Jack is doing a ten-year stretch in Sing Sing, Clever Charley is in hock at Joliet, and Sweet William is the only one who is at large--it must be William.' So he proceeds to locate William, and when they get him they have the man who did the work." As to those very interesting newspaper reports about how Detective So-and-So, while strolling down Broadway, saw a suspicious-looking individual whom he "piped" to the east side of the city, and eventually arrested in possession of property supposed to have been the plunder from a certain burglary, they are equally misleading. As the ex-officer, quoted above, said: "Ninety-nine out of a hundred cases are worked through the squeal of some thief, or ex-thief, who keeps posted on the doings of others of his class in the city. He knows some officer intimately; goes to him and tells him that the night before One-Thumbed Charley turned a trick on Church street, and the stuff is 'planted' at such and such a place. Acting on this information, the officers visit the place indicated, and just sit around and wait till their man shows up. Lots of ability about that, isn't there? Some people have an idea, you know, that after a burglary the detectives visit the house where it occurred, and, after examining certain marks on the window where the man got in, immediately say: 'This is the work of Slippery Sam; he is the only fellow who does this sort of work in this particular style.' Nothing of the kind. It's just as I've told you in ninety-nine cases out of a hundred. In the other cases, some citizen gives the officers information that leads to the capture of the man."