[Illustration: PLATE XIV. _By permission of_ _Kodak Ltd._ RÖNTGEN RAY PHOTOGRAPH OF BRITISH AND FOREIGN FOUNTAIN PENS. TAKEN ON WRATTEN X-RAY PLATE.] CHAPTER XXV ELECTRICITY IN MEDICINE One of the most remarkable things about electricity is the immense number of different purposes for which it may be used. We have already seen it driving trams and trains, lighting and heating our houses, and carrying our messages thousands of miles over land and sea, and now we come to its use in medical work. In the minds of many people medical electricity is associated with absolute quackery. Advertisements of electric belts, rings, and other similar appliances have appeared regularly for many years in our newspapers and magazines, and constant exposures of the utter worthlessness of almost all these appliances have produced the impression that medical electricity is nothing but a bare-faced fraud, while the disgusting exhibitions of so-called electric healing which have been given on the music-hall stage have greatly deepened this impression. This state of things is very unfortunate, because electricity, in the hands of competent medical men, is a healing agent of wonderful potency. Still another source of prejudice against electricity may be found in the fact that electric healing is popularly associated with more or less violent shocks. On this account nervously-sensitive people shrink from the idea of any kind of electrical treatment. As a matter of fact electric shocks have no healing value, but on the contrary they are frequently harmful, and a very severe shock to a sensitive person may cause permanent injury. No shocks whatever are given in electric treatment by medical men, and indeed in the majority of cases the treatment is unaccompanied by unpleasant sensations of any kind. In the previous chapter we spoke of the use of the Röntgen or X-rays in examining the various bones of the body. By means of the fluorescent screen it is quite easy to find and examine fractures and dislocations, and many of the diseases of the bones and joints can be seen and recognized. Metals are opaque to the X-rays, and so the screen shows plainly such objects as needles or bullets embedded in the flesh. Sometimes people, especially young children, swallow coins and other small metal articles, and here again the X-rays will show the exact position of the intruder. A particularly valuable application of the rays is in the discovering and locating of tiny fragments of metal in the eye, for very often it is quite impossible to do this by ordinary observation. Most of these fragments are of steel or iron, and they are most easily removed by means of an electro-magnet. If the fragment is very small a powerful magnet is used, one capable of supporting 500 or 600 lb.; but if it is fairly large a weaker magnet, supporting perhaps 30 lb., must be employed, because the forceful and rapid dragging out of a large body might seriously damage the eye.