PHOTOTHERAPY, the application of light rays to the treatment of such dis eases as tubercular glands, eczema, can cerous growths, lupus epithelioma, and acme vulgaris.
In the decomposition of sunlight or artificial white light, it has been found that different rays have different quali ties, some being calorific, or heat-produc ing, others producing light without heat. Experimentation has proved that there are rays beyond both extremes of the visible spectrum, called ultra rays. The ultra-red rays produce greater heat than the red ray, which is the extreme visible heat calorific ray.
The violet rays and ultra-violet rays are known to be bactericidal, since culture of bacteria which have been ex posed to their action are killed. These rays produce an inflammation (sunburn) and have the power of penetrating the skin.
Dr. Niles R. Fensen, of Copenhagen, Denmark, who introduced this work to the medical profession in 1892, is acknowledged to be the pioneer in the use of light rays for curative purposes. Since it is necessary to use some sort of filtering lens in order that the heat rays do not act upon the part to be treated, Dr. Fensen used an apparatus consisting of double quartz lenses, be tween which was placed an ammoniacal solution of sulphate of copper. This
solution is opaque to the ultro-red, red, orange, and yellow heat rays, but trans parent to the blue, violet and ultra-violet light rays.
White light must first be broken up into its component colors, and the heat rays removed by filtering, after which they are focused on the surface to be treated. In spite of the filter, artificial cooling of the surface undergoing treat ment is sometimes necessary.
The electric bath cabinet was invented by Kellog in 1894. In this case the patient is placed in a cabinet with his head projecting through an opening in the top, and his body subjected to a baking process, the heat being furnished by various lights inside the cabinet which are controlled by an attendant. This treatment is used for rheumatism, obesity, and for internal congestion.
In responsible hands there is no .doubt that much benefit is derived by the practice of these methods, and there are many reputable sanitariums and prac titioners of phototherapy, but it has also given rise to many drugless health re sorts and other questionable institutions whose object is to prey upon the helpless and infirm.