THE ABIOTIC ACTION OF ULTRA-VIOLET LIGHT.
Typhoid bacilli are about one two-hundredth as sensitive to ultraviolet light of wave-lengths 2100 to 2800 Angström units as is the photographic plate. This sensitivity then falls off, decreasing rapidly to almost zero sensitivity at about 2970, the beginning of the sun's spectrum.
Laboratory of the Henry Phipps Institute of the University of Pennsylvania, Philadelphia.
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