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Hie Action on Bacteria of Electrical Discharges of High Potential 



and Rapid Frequency. 

 By Alexander G-. E. Foulerton, F.E.C.S., and Alexander M. Kellas, Ph.D. 



(Communicated by Professor* J. Bose Bradford, M.D., F.E.S. Eeceived 

 March 30,— Eead May 3, 1906.) 



(From the Laboratories of the Middlesex Hospital.) 



In the course of an investigation into the action of " high frequency " 

 electrical discharges as they are used in the practice of medicine, we have 

 inquired more particularly into the action of such discharges on bacteria 

 exposed to their influence under various experimental conditions. 



I. General Procedure in Experiments, and Electrical Apparatus 



Used. 



The bacteria used for the purposes of our experiments have included the 

 following species: — 



B. anthracis, B. diphtherial, B. typhosus, B. coli communis, B. dysenterim 

 (Shiga), B. pyocyaneus, and Micrococcus pyogenes aureus, together with some 

 saprophytic species, B. megaterium, B. prodigiosus, and Micrococcus agilis. 



In our experiments the bacteria have been exposed to the action of the 

 discharges under the following conditions : — 



(1) The discharges have been- sprayed on to the surface of distilled water, 

 tap water, and normal saline solution in which the bacteria were suspended ; 

 and with these circumstances the current has been discharged in different 

 atmospheres above the bacterial emulsion, experiments having been carried 

 out in common air, hydrogen, nitrogen, carbon dioxide and carbon monoxide. 



(2) The discharges have been sprayed directly on to the surface of cultures 

 of the several bacteria whilst growing on nutrient-agar and various other 

 solid culture media. 



(3) The discharges have been sprayed directly on to the surface of thin 

 films of the bacteria spread out on small slabs of plaster of paris. 



And, in addition, we have tested the action of rapidly oscillating electrical 

 currents of high potential when passed directly through bacterial emulsions 

 without interruption by discharge above the surface of the fluid. The 

 experimental conditions included under (2) and (3) above were soon found to 

 be unsatisfactory, inasmuch as a high degree of heat was quickly con- 

 centrated in the solid material on which the bacteria were exposed, and it 



