SHORT ELECTRIC WAVE RADIATION 543 



to be the case. It is here, then, in the region of relatively short electric 

 waves and with special apparatus for the concentration of the waves, that 

 we find the biologist at work. He discovers at the very beginning of 

 his work that in this as in other regions of the electromagnetic spectrum 

 the waves exert a potent influence on living material. 



BIOLOGICAL EFFECTS 



The biological effects of high-frequency electric fields as generated by 

 the vacuum tube appear to have been first investigated by Gosset, in 

 1926, and his coworkers in France. Schereschewsky (27, 28), Christie 

 and Loomis (5), and McKinley (13) were the first American workers to 

 use the new three-electrode vacuum tube, while SchUephake (30, 31) 

 appears to have been the first in Germany. 



Gosset and his coworkers, Gutman, Lakhovsky, and Magrou, studied 

 the effects of very high frequency fields upon plant tumors caused in 

 Geranium by Bacterium tumefaciens. They reported that exposure of 

 the plants to this radiation brought about, eventually, a necrosis of the 

 tumors. 



Schereschewsky (27) seems to have been the first to subject animals 

 to the action of high-frequency fields as generated by the vacuum tube. 

 He found that exposure caused severe symptoms which might result in 

 death if the exposure was prolonged more than a few minutes. Some, 

 at least, of these symptoms he thought to be due to heat retention. 

 Besides this acute lethal effect, he found that exposure caused destruction 

 of tissue. After sublethal exposures, in many instances, small hemor- 

 rhagic areas were observed along the course of blood vessels of the ears 

 and within a few days the ears became necrotic and dropped off. This 

 was also true of the tail. 



Schereschewsky used mice in his work and found considerable indi- 

 vidual variation in response to the influence of the radiation and part 

 of his early work consisted in determining the average lethal time for 

 various frequencies. Differences in individual response to the radiation 

 made his later work difficult and have been a source of trouble to all 

 other workers in biology. This same individual variation was studied in 

 1930 by McKinley and Charles (15) using an insect (the parasitic wasp 

 Hahrohracon) and the coefficient of variability in a series of closely con- 

 trolled experiments at a constant frequency was found to be more than 

 56 per cent. 



Schereschewsky attempted to compare the effect of various fre- 

 quencies and to establish an optimal frequency for lethal action on the 

 mouse. He described such optimal frequencies, and came to the con- 

 clusion that the frequencies of highest lethality lay between 18,000,000 

 and 66,000,000 cycles per sec. He ascribed the phenomena at that time 

 to the specific action of the radiation in the form of electromechanical 



