ULTRAVIOLET LIGHT AS A SANITARY AID ' 



By Louis Gershenffxd, B. Sc, P. D., Pb. M., D. Sc. 



Professor of Bacteriology and Hygiene, Philadelphia College of Pharmacy 



and Science 



Man always has been interested in keeping healthy. When germs 

 were found to be responsible for the causation of many diseases, vari- 

 ous methods were attempted to eliminate these agents detrimental to 

 our health. Of the natural agencies associated with health and clean- 

 liness, sunlight has been regarded by the majority of persons as the 

 most beneficial. The heretic Pharaoh Ikhnaton more than 3,000 

 years ago insisted that the sun is God and it is the only source of life 

 and goodness. Herodotus, the prominent Egyptian physician, some 

 500 years later stated that sunlight is required especially for people 

 who need restoration of muscular energy. The use of sunlight as a 

 weapon in the treatment of disease is to be noted and can be traced 

 throughout the ages. After our knowledge concerning bacteria and 

 other microorganisms increased and their relationship with disease 

 was proved, physicians advocated the use of sunlight in many diseases 

 and for the destruction of all organisms. 



It was about 65 years ago, in 1877, that Downes and Blunt first 

 showed that sunlight killed bacteria. They demonstrated that expo- 

 sure of putrescible fluids to direct sunlight in the presence of air would 

 stop all growth. Ten years later, Roux confirmed these findings and 

 showed that anthrax spores were destroyed by exposure to the direct 

 rays of the sun. In 1892, Ward, using natural sunlight, demonstrated 

 by actual tests that the actinic rays were responsible for the destruc- 

 tion of anthrax spores. About the same time and since then various 

 workers reported that ultraviolet light possessed a germicidal effect. 

 In 1903, Barnard and Morgan noted that the germicidal action of 

 sunlight is limited to certain of the sun's rays. Later these same 

 workers, using the spectra of carbon and other artificial sources of 

 light for obtaining ultraviolet rays, were able to kill anthrax spores. 



1 One of the Popular Science Lectures, delivered at the Philadelphia College of Pharmacy 

 and Science during the 1040 Series. Reprinted by permission from The American Journal 

 of Pharmacy, vol. 114, No. 1, January 1942. 



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