The Survival of Microbes in Modulated High‐frequency Voltage Fields

SUMMARY: Resting suspensions of baker's yeast, Bact. coli , tabacco mosaic virus, and a bacteriophage, were subjected to high frequency electric fields in cells which kept the temperature below 30°, very energetic cooling being necessary. The fields applied were of two kinds: (i) frequency 10 Mc/s., modulated with a half‐sine wave of frequency 50 c/s.; modulated at frequencies from 10 to 120 Kc/s. with rectangular pulses varied from 1/3 to 1/15 of the complete cycle. The voltage gradients used were up to 2,000 V/cm. and were applied for aggregate periods up to 12 min., but no significant kills were observed. It is computed that any specific lethal effect too small to be detected in these experiments could have little pracrtical value.