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A TEXTBOOK OF PHYSIOLOGY 



necessary to kill if passed in one direction only, may be oscillated 

 without any contraction being produced, provided it be oscillated 

 frequently enough. The result of such a current is an agreeable 

 sensation of heat. This forms the basis of " high-frequency " treat- 

 ment, or " diathermy." When these high-frequency currents are 

 passed through the body, part of the electrical energy is transformed 

 into heat, which is produced in all parts, both superficial and deep, 

 in which the current flows. The effects of diathermy, so far as can 

 be seen, are produced through their thermal action, and the same 

 results can be obtained by the simple use of hot baths. 



