[ . the Effect of Monochromatic Ultra - Violet Light upon Vaccine Virus

I t has been known for many years tha t ul tra-violet light is bactericidal. Finsen and Dreyer (1), in 1903, were probably the first to Show tha t light with short wave-lengths is virucidal also. More recent ly (2-7) other reports have appeared dealing with the effects of ul tra-violet irradiation upon bacteria, viruses, and enzymes. For the most par t , however, single wave-lengths have not been used in the investigations, nor have the workers determined or taken into consideration the amount of energy required to kill or to inact ivate these agents a t single wave-lengths in the active ultra-violet region. One of the present authors (Gates) is making a quant i ta t ive s tudy of the action of ul tra-violet light on certain active agents in the hope of obtaining addit ional information concerning their nature. In the present paper the results of the studies concerning the effects of ultraviolet irradiation upon one of these active agents, vaccine virus, will be presented. Methods and Materials.