SHORT ELECTRIC WAVE RADIATION 545 



difficulties to be pointed out later, but under strong dosage it was 

 evident that the animal body was subjected to the equivalent of a high 

 degree of external heat. MacCreight and McKinley (12) attempted 

 an indirect measure of the heat generated in the body of young rats when 

 subjected to a dosage which killed them in about 5 min. They found 

 that although the rectal temperature at death never rose higher than 

 46°C., the actual temperature to which the animal was subjected was 

 much higher. They compared the macroscopic picture as presented 

 by animals killed by high-frequency fields and those killed by various 

 degrees of external heat and found that only when external temperatures 

 reaching 160°C. were used, did the effects of external heat compare to 

 those of the high-frequency field. 



That the amount of heating in all tissues is not the same was pointed 

 out by Schliephake (31). Schliephake compared the action of short elec- 

 tric waves (2.8 meters) with the action of ordinary diathermic currents, 

 in the heating of particular tissues. He found that diathermy (fre- 

 quencies of 100,000 cycles per sec.) selectively heated the fatty tissue, and 

 that the short electric waves heated liver and bone to the greatest 

 extent, these data being obtained by the use of the rate of cutaneous 

 heating as a standard. McLennan and Burton (19) confirmed these 

 observations, and were in accord with Schliephake regarding the depth 

 of action of the high-frequency field. They were of the opinion that at 

 these high frequencies the so-called electrical "skin effect" in tissues is of 

 little significance, it being more probable that the radiation passes 

 directly through the living cell rather than around it in the intercellular 

 substance. 



Further heating-effect studies were made by several other workers. 

 Richards and Loomis (25a) found that the heating effect for electrolytes 

 in a high-frequency field has a maximum that depends on conductivity 

 and frequency. Kahler, Chalkley, and Voegtlin (11), working with a 

 protozoan, Paramecium caudatum, came to the conclusion from their 

 experiments that the lethal effect was due entirely to heat. They found 

 that death occurred at the same temperature whether the organism was 

 killed by an agent of external heat or by a high-frequency field. 



SYNTHETIC FEVER 



Another group of papers dealing with the temperature aspects of ele- 

 vated temperatures in general and in particular with those induced by 

 high-frequency irradiation has been adequately summarized by Carpenter 

 and Boak (3) and these workers themselves reported that high-frequency 

 irradiation (wave-length 30 meters) causes elevations of temperature and 

 prevents the development of experimental scrotal chancres in rabbits. 



Carpenter and Page (4), taking advantage of the very quick and 

 certain heating effect of exposure to the high-frequency field, were able 



