Glassw Electrodes
Vacuum and Non-vacuum, Electrodes.—With high-fre¬quency machines two kinds of glass electrodes are used. One is of clear glass, filled with air or rarified gas of some kind, and is similar to the small glass applicators of the “violet-ray” ma¬chines so extensively advertised and sold in which the violet light flickers during use. The other is metal-lined and is about ten times as effective as the unlined applicator. When the metal-lined electrodes are applied to the part to be treated they produce heat in the tissues beneath—as much as two inches below the surface. This is a kind of indirect diathermia, differing from the direct in that the heat is generated only at a limited distance beneath the applicator, while in the direct it may, by the proper arrangement of the two electrodes, be generated anywhere. The former is, however, an excellent means of producing heat at some point not much below the surface and in the mucous membranes. There are numerous shapes of electrodes, for surface work and for reaching the mucous membrane of cavities, such as the nose, mouth and throat, vagina, urethra, arid rectum.