ULTRAVIOLET LIGHT MEIER 353 



general question as to whether they are enzymatic or chemical in 

 nature, or whether they are entirely bacterial. The bacteriophage 

 is maintained by one school of WHjrkers to be a living ultramicro- 

 scopic virus. Another school considers it to be an inanimate agent 

 developed by the microbe as a result of the reaction between the 

 invading organism and the tissue of the host, and that by the heredi- 

 tary vitiation of the organism a lytic or cell-destructive principle is 

 developed. 



An example of the bacteriophage is the filterable substance ob- 

 tained from patients recovering from bacillary dysentery which will 

 dissolve cultures of the Shiga bacillus. A few drops of the dis- 

 solved culture reproduces the same phenomenon on addition to an- 

 other culture, etc., indefinitely. The lytic property increases by dilu- 

 tion and retains its activity for several years. 



With ultraviolet rays, Zoeller (1923) accomplished the inactiva- 

 tion of the bacteriophage. Mizuno (1929), a Japanese worker, has 

 also reported the absolute destruction of the bacteriophage in the 

 ultraviolet. McKinley, Fisher, and Holden (1926) determined the 

 lethal effect of ultraviolet light on the bacteriophage and on two 

 filterable viruses : herpes and Levadti's so-called " encephalitis 

 virus ". 



Numerous workers have made experiments in which the inactiva- 

 tion of filterable virus diseases is accomplished by ultraviolet irra- 

 diation. Oblitsky and Gates (1927) studied vesicular stomatitis of 

 horses and found that the similarity with the response of this virus 

 to that of a common bacterium to ultraviolet suggests that the sub- 

 stance of the virus is similar in character and chemical constitution 

 to bacterial protoplasm. 



Rivers, Stevens, and Gates (1928), working with the inactivation 

 of vaccine virus by ultraviolet rays, found also that rabbit skin 

 treated for a few minutes with ultraviolet light and then inoculated 

 at once with vaccine virus is less susceptible to the action of the virus 

 than is untreated skin. 



Since bacteria retain their power to produce diseases and to ag- 

 glutinate blood even after they have been killed by ultraviolet rays, 

 an improved method for the sero-diagnosis of typhoid and para- 

 typhoid fever has been proposed by Lematte. Emulsions of these 

 disease-producing bacteria that have been killed by the ultraviolet 

 rays are added to test tubes containing the diluted blood of the 

 patient to see if agglutination will occur (Laurens, 1933). 



A potential side reaction of the ultraviolet effect on bacteria has 

 been reported by Eberson (1920). He exposed types of meningo- 

 cocci to ultraviolet irradiation and studied the power of stimulating 

 in animals the formation of defensive antibodies. He found that the 



