In one clear case of murder, detection was aided by the simple discovery of a few half-burnt matches that the criminal had used in lighting candles in his victim's room to keep up the illusion that he was still alive. A dog, belonging to a murdered man, had been seen to leave the house with him on the morning of the crime, and was yet found fourteen days later alive and well, with fresh food by him, in the locked-up apartment to which the occupier had never returned. The strongest evidence against Patch, the murderer of Mr. Blight at Rotherhithe, was that the fatal shot could not possibly have been fired from the road outside, and the first notion of this was suggested by the doctor called in, afterwards eminent as Sir Astley Cooper. In the Gervais case proof depended greatly upon the date when the roof of a cellar had been disturbed, and this was shown to have been necessarily some time before, for in the interval the cochineal insects had laid their eggs, and this only takes place at a particular season. We shall see in the Voirbo case, quoted above, how an ingenious police officer, when he found bloodstains on a floor, discovered where a body had been buried by emptying a can of water on the uneven stones and following the channels in which it ran. [Illustration: TAKING MEASUREMENTS OF CRIMINALS (BERTILLON SYSTEM).] Finger-prints and foot-marks have again and again been cleverly worked into undeniable evidence. The impression of the first is personal and peculiar to the individual; by the latter the police have been able to fix beyond question the direction in which criminals have moved, their character and class, and the neighbourhood that owns them. The labours of the scientist have within the last few years produced new methods of identification, which are invaluable in the pursuit and detection of criminals. The patient investigations of a medical expert, M. Bertillon, of Paris (one of the witnesses in the Dreyfus case), developing the scientific discovery of his father, have proved beyond all question that certain measurements of the human frame are not only constant and unchangeable, but peculiar to each subject; the width of the head, the length of the face, of the middle finger, of the lower limbs from knee to foot, and so forth, provide such a number of combinations that no two persons, speaking broadly, possess them all exactly alike. This has established the system of anthropometry, of "man measurement," which has now been adopted on the same lines by every civilised nation in the world. The system, however, is on the face of it a complicated one, and at New Scotland Yard it has now been abandoned in favour of the finger-prints method. Mr. Francis Galton, to whose researches this mode of identification is due, has proved that finger prints, exhibited in certain unalterable combinations, suffice to fix individual identity, and his system of notation, as now practised in England, will soon