The provisions of this Act were afterwards extended to robberies in London,[141] and first and last were responsible for an appalling sum of wickedness. The bait of blood-money and the lack of a salaried or professional class of detectives were answerable for the appearance of amateur thief-takers; these men were mostly ex-thieves, who had given up their old vocation for the safer, more lucrative, but infinitely baser role of fattening on the conviction of the innocent, and on the execution of those whom they had themselves corrupted. The best known and most energetic member of this horde of vampires was the notorious Jonathan Wild, who flourished at the beginning of the eighteenth century, and whose _modus operandi_ is fully set forth for us by Henry Fielding in his satirical history of "Jonathan Wild the Great." This arch-ruffian had a most complete knowledge of all the thieves in England, and at one time practically monopolised in his own person the trades of receiver of stolen property and trafficker in blood money. He established warehouses all over the country, and even bought himself a ship to export what he could not dispose of at home. To those thieves who submitted to his authority, and who brought him the proceeds of their robberies, he extended a protection that must have been dependent to a certain degree on the connivance of some person or persons in authority. Grandmaster of espionage, and holding in his talons the threads of all villainy, Wild could manufacture whatever evidence he chose, could ruthlessly destroy any who opposed him, and deliver up to justice those thieves who were bold enough to take their spoils elsewhere for disposal. When this supply of victims ran short, or when it suited his purpose to shield the real culprit, he was content to take the reward offered for the conviction of the innocent. It is comforting to know that his carcass, the foulest fruit the fatal tree ever bore, eventually swung at Tyburn, at the same spot where so many of his victims had preceded him. The iniquitous system of paying blood-money for the conviction of certain classes of offenders continued for generations, but is now happily extinct. At the present day rewards are not offered by Government except under very exceptional circumstances, and then only in cases where the identity of the criminal is clear, whilst rewards offered by private persons are placed under restrictions that prevent any revival of the abominable traffic that continued even into the nineteenth century. As late as 1816 George Vaughan, and others associated with him, were convicted at the Middlesex Sessions of conspiring to induce three brothers named Hurley, and a lad named Wood, only thirteen years of age, to commit a burglary at Hoxton, and by having them convicted of the fact, to procure for themselves the rewards given by Parliament for the conviction of housebreakers.