Ultraviolet quickly than violet light itself. He called them "oxidizing rays" to emphasize chemical reactivity and to distinguish them from "heat rays", discovered the previous year at the other end of the visible spectrum. The simpler term "chemical rays" was adopted shortly thereafter, and it remained popular throughout the 19th century, although there were those who held that these were an entirely different sort of radiation from light (notably John William Draper, who named them "tithonic rays"). The terms chemical rays and heat rays were eventually dropped in favor of ultraviolet and infrared radiation, respectively. In 1878 the sterilizing effect of
Ultraviolet light therapy practices for the treatment of cosmetic skin conditions (such as psoriasis, acne, eczema and vitiligo) and in indoor tanning salons for cosmetic tanning. At least 88 percent of dermatologists recommend the usage of tanning equipment or salon tanning for clients to inexpensively self-treat skin conditions as a convenient alternative for clients in rural locations, as well as naturally occurring exposures including ultraviolet light from the sun. Typical treatment regimens involve short exposure to UVB rays 3 to 5 times a week at a hospital or clinic, and repeated sessions may be required before results are noticeable. Almost all of the