From its injurious aspects we turn now to its beneficial qualities. The arc-light by its brilliance is not good for the eyesight when looked at direct, but there is probably nothing harmful in the light itself, unless it should be the excess of violet rays. It is a cool light; and hot lights, by drying the natural humours of the eye, are the most prejudicial to the sight. The incandescence light which is free from excess of violet rays is also a cool light; and as it neither pollutes nor burns the air of a chamber, it is the best light for a student. Small reading-lamps, fitted with movable arms carrying incandescent bulbs, are now manufactured for this purpose. Even with the incandescence lamp, however, it is advisable not to look at the brilliant filament. Surgeons and dentists find these little incandescence lamps of great service in examining the teeth and mouth. Some are made no larger than a pea. Others are fitted into silver probes (cooled by circulating water) for insertion into the stomach to illuminate its coats, or enable a physician to diagnose other internal organs. Dr Payne, of Newcastle-on-Tyne, recently made an examination of the liver by inserting one of these endoscopes into it through an incision made in the abdomen. M. Trouvé has also fitted a small lamp to a belt which goes round the physician’s forehead, thereby enabling him to direct the light to where he is looking. Another experimenter has so applied the light that he has been able to photograph the vocal chords while in the act of singing; and a third has illuminated the whole interior of a living fish, so that all the main physiological operations could be witnessed by a class of students. Such services as these could not be rendered by any other known illuminator. HUSH-MONEY. Out of the countless variety of evil-doers who thrive upon the misfortunes of their fellow-creatures, and are enabled to gain a means of livelihood by the folly and timidity of their dupes, one class above all others seem to conduct their depredations with much success, on account of the defenceless position of the unhappy individuals upon whom they prey. We allude to those who make it their business to levy what is termed ‘hush-money.’