Every division of police in London has its detective detachment of from twelve to thirty men under divisional inspectors. Except in a very few of the outlying rural districts of London, there is no police station without one or more detectives. They are expected to hold local crime in check. But the machine is adaptable to contingencies. The "morning report of crime" sent to headquarters shows daily the ebb and flow of crime. A sudden wave of burglaries, for instance, might be met by reinforcements from another district or from the Yard itself. Twice a month the big Council of Crime meets--a gathering at New Scotland Yard at which thirty or forty of the senior detectives of the metropolis, heads of districts, and headquarters men meet in conference and compare notes. The movements of criminals are checked, particular mysteries discussed. A. is puzzled by certain peculiarities in a robbery at Hampstead; B. remembers that similar peculiarities were present in an affair in which he arrested Bill Smith, at Brixton, some years ago. Resolved unanimously that Bill's recent movements will bear looking into. Opinions will be discussed of the identity of a swindler who has been duping furniture dealers by selling them furniture from houses or flats he has rented. Many a fraud has been detected by these informal discussions in that bare green-painted room. One of the greatest difficulties that beset a detective of real life--it does not so much affect the detective of fiction--is the securing of evidence that is legally convincing. It is one thing to be morally certain of a person's guilt; it is quite another thing to prove it to the satisfaction of a jury. Especially is this so in case of murder. There is probably no other great city in the world which can boast of no murder mystery in which for two years the perpetrator remained undiscovered. There were twenty-five cases of murder in 1913--the last year for which figures are available--and twenty-four in 1912. In each one, in 1912, the guilty person was known. The 1913 cases were thus disposed of. Eleven arrests were made--one of a man who committed two murders--and in nine the murderers committed suicide. Three of the other cases were caused through illegal operations, which were not immediately reported to the police. The remaining case was that of an Italian who fled abroad. The real detective is a common-place man--common-place in the sense that you would not pick him out of a crowd for what he is. He assiduously avoids mannerisms. You will find him genial rather than mysterious. He does not wear policeman's boots, and he is not always weaving a subtle network of deductions. He is a plain business man of shrewd common-sense who has been carefully trained to take the quickest and most accurate way to a desired end. You can almost fancy him drawing up an advertisement: