Studies on Microorganisms in Simulated Room Environments: III. The Survival Rates of Streptococci in the Presence of Natural, Daylight and Sunlight, and Artificial Illumination.

In a previous paper (Buchbinder and Phelps, 1941) a method was described whereby the survival rates of streptococci in simulated room environments may be determined with the use of a petri plate technic. It was found by this method that the death rates of streptococci in the dark under these simulated room conditions were geometric and that the median survival time (m.s.t.), of the three strains studied ranged from one to 13 days. The study of these strains by this technic is extended in the present paper to include the effect of different types of room illumination, both natural and artificial, on the survival rates. The method used in these experiments was to simulate in turn the effect of each new factor, daylight, sunlight, and artificial light, on the organisms in a normal room environment.