The age-herald., 1900-11-11

the authorities of the London Hospital to try the cure. Her Royal Highness pre- scented them with the necessary appara- tus, of which the total cost was f5OO.
 The method is a curious though simple one. If any one visits the London Hospi- tai between ? and 5 D. m on any day of the week he will find, in bright, cheerful room set apart for the purpose, number of patients sitting on rocking chairs in circle around the room. Hanging from the ceiling in the center is a very powerful electric lamp. And around it are arranged several telescopes, which concentrate the light on the patients. Beside each patient is a nurse who presses small glass lens on the spot of skin under treatment.
 To understand 1t all we must go back to the first experiment.
 As every one knows, white light-the light of the sun, electric light, etc., con sists of a combination of all the colors of the rainbow At one side of the rainbow are the red and yellow rays; at the other side the violet and blue. The red and vel low rays are carriers of heat: the blue and violet are called chemical rays. That Is to say, they are almost without heat but they cause chemical action.
 For instance, if you mix the two gases hydrogen and chlorine in a thin bulb of glass and then focus the red rays Of llght on it, nothing happens. But if you focus the violet rays there is an immediate eX- posion. The photographer has reason to understand this. When piece of photo graphic paper is exposed to the light 1t blackens But if ruby lamp is used no darkening of the paper follows, the red glass not allowing the violet chemical rays to come through.
 Now some time ago a doctor put a piece of photographic paper under the skin Of dog and focused the violet rays of sunlight t1,a,. t,ia1 in and kept him in a dark room. The result was that the first piece of paper was black ened and the second unaffected. This seems a useless sort of eXperiemnt, but 1t was the first step in the great discovery. It proved that the chemical rays of light can pass through the skin.
 At the same time attention was directed to the curious fact that mountain climbers suffer badly from sunburn when passing over a field of snow, with the thermometer below zero. To elucidate this matter the following experiment was made. Sunlight was concentrated on the face of two men, red glass being interposed in one case and blue glass in the other. The red glass all lows all the heat of the sun to pass through, but kept off the violet chemical rays. The blue glass Jet the chemical rays through, but kept out the~warm red light. After the experiment it was found that the man whose face was nearly roasted by the red light came out of the ordeal without trace of sunburn, but the man on whom the cold chemical rays fell was badly sun burned. Therefore the doctor concluded that the chemical rays were very irritating to the skin.
 If the chemical rays do this to a mans skin, he thought, no doubt they will have a destructive effect on miscrobes.
 Further experiment showed that bright sunshine killed the strongest of miscrobes- the bacillus prodigiosus-in one hour and a half. A powerful electric light killed them in nine hours. But by excluding the red heat rays and concentrating the vio- let chemical rays, 1t was found that nearly all miscrobes were killed in a few seconds.
 Putting all these facts together, it was now known that the concentrated light of the sun or electric arc would kill miscrobes the skin, in the substance of the skin, and even under the skin. In all probabil- fty, therefore, any skin disease due to mi- crobes could be cured by light. Now, there is one such disease, a terrible infliction, which was the despair of the doctors. That is lupus, a first cousin of consumption,