REVIEW OF LITERATURE
Effect of Radiation on Bacteria.—Ever since the experiments of Downes and Blunt in 1877 it has been known that ultraviolet radiation exerts a lethal action on bacteria. Grimm and Weldert1 employed a quartz mercury vapor arc of 1,200 candle power and exposed clear water containing less than 100 bacteria per cubic centimeter. This was sterilized at a rate of 0.55 cubic meters per hour.
Bovie2 (1915) studied the germicidal power of radiation of from 250 to 300 millimicrons and found that radiation of wavelengths shorter than 292.5 millimicrons killed bacteria and spores of various fungi in ten minutes but that radiation of a wavelength 2.5 millimicrons longer did not kill them in two hours.
Burge3 studied the bactericidal action of the quartz mercury vapor lamp on seven kinds of nonfluorescent bacteria and eight fluorescent forms. He found that an exposure of two