376 ULTRA-VIOLET LIGHT ON BACTERIA AND PRODUCTS 



Temperature has little effect, but the reaction of the substratum is important. In acid 

 media enzymes are more sensitive than in an alkaline medium. Salts and organic 

 colloids protect enzymes against the action of light. Previously Agulhon' had worked 

 with such enzymes as sucrose, emulsin, and rennet and noted the destructive action 

 of ultra-violet light. Some enzymes appeared to be acted upon only in vacuo; others 

 were destroyed both in the presence and absence of oxygen. In view of most of the 

 other work with light-waves, the oxygen effect may properly be questioned. 



Bacteriophages are gradually destroyed by ultra-violet light. Fisher and McKin- 

 ley^ have found that the resistance to this agent is proportional to the concentration 

 of the lytic principle. 



Two investigations have been made on the effect of ultra-violet radiation on 

 diphtheria toxin — one by Lowenstein^ and the other by Hortock, Schurmann, and 

 Stiner.t The latter conducted a series of experiments in which they recirculated a 

 toxin solution through an ultra-violet-light sterilizer and determined the effect on the 

 minimum lethal dose. Very long periods of recirculation (six to ten hours) were nec- 

 essary to produce any marked change in the toxic action. Direct exposure of toxic 

 broth to ultra-violet light also had little effect except after very long periods of time. 

 Their experimental data are somewhat meager. It is impossible to calculate the actual 

 time of exposure of any particle of toxin in the recirculating experiments on the basis 

 of data presented. In the medium in which bacterial toxins are found or are produced, 

 they appear to be relatively stable toward ultra-violet light. 



On the other hand, antibodies are undoubtedly sensitive to irradiation. Heuer's^ 

 claim that agglutinins produced against organisms of the typhoid-paratyphoid group 

 react differently has not been substantiated. He states that bacteriolysins are sensi- 

 tive to light rays. I can find no evidence in regard to the action of ultra-violet rays 

 on antitoxins. Tuberculin is probably affected. 



The antibodies to which particular attention has been paid are the so-called "am- 

 boceptors" or "sensitizers" against red blood cells. All investigators from Huber^ to 

 the present time agree that hemolysins are readily destroyed by ultra-violet irradia- 

 tion. Friedberger and Scimone^ also report that Wassermann positive sera become 

 negative after exposure to these rays. All investigators agree as to the sensitiveness 

 of alexin (complement) to ultra-violet rays. The work of Brooks^ in this connection 

 should be particularly noted as well as that of Hill and Schmidt.' The results obtained 

 by the latter indicate that alexin is less resistant than sensitizer and that both are 

 protected by proteins and certain amino acids such as tyrosin and phenylalanin. There 



" Agulhon, L. H.: Compl. rend. Acad, dc Sci., 153, 779. 1911. 

 ' Fisher, R., and McKinley, E. B.: J. Infect. Dis., 40, 399. 1927. 

 3 Lowenstein, E.: Zlschr. exper. path. Therap., 15, 279. 1914. 



''Hortock, O., Schurmann, W., and Stiner, O.: Zlschr. f. Immunitdtsjorsch. u. exper. Therap., 

 21, 643. 1914. 



sHeuer, G.: Centralbl.f. Baktcriol., Abt. I, 88, 3S0. 1922. 



^Huber, H.: Arch. J. Uyg., 54. 53- iQOS- 



7 Friedberger, E., and Scimone, V.: Zlschr. Immunildtsforsch. u. exper. Therap., 37, 341. 1923. 



* Brooks, S. C: J . General Physiol., 3, 169, 1S5. 1920. 



*< Hill, F. McC, and Schmidt, C. L. A.: J. Infect. Dis., 25, 335. 1919. 



