RONTGEN RAYS

If a gla bulb be fitted with two platinum disks A and K, the latter being spherical and concave towards A, and if the disks be connected with the terminals of a powerful induction coil, and interesting series of phenomena is displayed as the air in the bulb is gradually removed by an air pump. At first a series of sparks, following zigzag paths resembling lightning, pa es between the disks. As the exhaustion proceeds, these sparks spread out into a luminous brush-like discharge which fills the intermediate space. Later on, this brush discharge shows striations perpendicular to its length; then a dark space appears at K, and extends until it reaches to A and to the walls of the bulb, which then become phosphorescent. The dark space contains lines of faintly luminous matter, and these, since they proceed from the disk K (known as the kathode), are termed kathode rays. When these rays fall upon the anode A, they produce there disturbances which travel outwards in all directions from the face of the anode, and these disturbances are termed ‘Rontgen rays.’ They were discovered by RGntgen in 1895, and were first known as ‘X-rays.’ They are believed to be due to pulsations in the luminiferous ether, and to travel through that medium with a speed approaching that of light. The kathode rays consist of streams of negatively charged particles, or electrons, and when an electron strikes the anode {ts course is suddenly arrested, and this es rise to the pulsational disturbance own as the Rontgen ray. The chief property of these rays is that they can pa through matter which is opaque to light, and as a rule the le dense such matter is the greater is the ease with which they are transmitted. The rays are also capable of affecting a photographic plate, and of producing phosphorescence on a screen coated with barium platinocyanide. This, together with the absorption of the rays by denser substances, makes it po ible to show on @ photograph or screen the structure of different Darts of the human body, the bones being distinguished by their darker shade. Another important property of the rays is that they are capable of ionizing a gas. Rodntgen rays differ from light in several important respects. They cannot be refracted or polarized; their reflection from any surface is a diffuse reflection which dces not follow the laws of reflection in light; and phenomena of interference and diffraction have not, so far, been observed in them, Rontgen rays are employed by surgeons not only for diagnostic purposes— as in the diagnosis of fractures, dislocations, calculi, foreign bodies—but in the treatment of various conditions. Cancers and sarcomas treated by apDlication of these rays diminish in growth, and rodent ulcer, which is a form of cancer, may be completely cured if it has not progre ed too deeply. In many skin diseases, especially ringworm and chronic skin conditions, they generally effect a cure, and they have a@ valuable influence on lupus, although a relapse is common in that disease. The swollen condition of the spleen in leukemia is reduced by application of Roéntgen rays, and the enlargement of lymph glands in tuberculosis (scrofula) and lump hade noma can also be reduced by this method. The rays have a destructive effect upon the normal healthy ti ues, and these must be protected both by careful regulation of the quantity of rays emitted and by enclosing the R6dntgen rays tube in an impermeable box with a suitable opening in it for the pa age of the rays.