Identifier: lightenergyitsph00clea (find matches)
Title: Light energy, its physics, physiological action and therapeutic applications
Year: 1904 (1900s)
Authors: Cleaves, Margaret Abigail, 1848-1917
Subjects: Medicine, Physical Phototherapy Light Radioactivity
Publisher: New York, Rebman company (etc., etc.)
Contributing Library: Yale University, Cushing/Whitney Medical Library
Digitizing Sponsor: Open Knowledge Commons and Yale University, Cushing/Whitney Medical Library

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energyof the high frequency waves of the arc, for by the absenceof condensing lenses, and the nearness of approach to thepatient little, if any, opportunity is offered for their disper-sion. By the Position of the Carbons the Light of the Arc, orBlue Mist and Reflection from the Crater is Secured.—Theposition of the carbons at an angle of 45 degrees is also afactor for the light of the arc proper or blue mist is fullyexposed to the inner quartz plate, the crater of the positiveelectrode serving at the same time as a reflector. This ismost important, for, as has been noted, the chemical rayshave short wave lengths and high frequencies, and can agi-tate little things in their path, such as molecules, and as thisagitation is what is assumed to effect chemical change, it ismost important that every opportunity of dispersion ofactivity in transit from the source to the patient should beminimized. With this apparatus, Lortet and Genoud find that CONCENTRATED ELECTRIC ARC LTGHT ENERGY. 473
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Fig. 19.—Victor Lamp. Fig. 20.—Lortet et Genoud Lamp. 474 LIGHT ENERGY. an exposure of from 15 to 20 minutes suffices against anhour and a quarter with the Finsen tube. This is due to thesecuring of a residual beam of much greater total energythan is obtained from a tube with condensing lenses ofquartz. This residual beam, to be properly effective, mustpossess the greatest possible number of high frequencywaves of considerable amplitude, a beam not only of highintrinsic energy, but greater total energy. As the amountof work accomplished always depends upon the amount ofenergy expended, it follows that a shorter exposure shouldgive equally, if not better results. But one factor minimizesthis effect, and that is the absence of condensing or focallenses of quartz, as will be shown in a comparative estimateof different light mechanisms. They are, however, suppliedby the manufacturers. The effect desired in lupus, for ex-ample, must be produced by the maximum of chemicalactivity, which

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