578 



C. S. BACHOFER 



20 



20 



40 



MINUTES 



60 



80 



Fig. 2. Effect of x-rays on bioelectrical responses of rat caudal nerves irradiated 

 in vitro. Mean relative activities are plotted as a function of time of x-irradiation. The 

 values represent the ratio of the activity at a designated time relative to the activity at 

 the beginning of x-irradiation. In this and other graphs, irradiation continued until 

 nerves failed to respond, unless otherwise indicated. Dose rate: 6 kr/min. 



lation with those under stimulation at 50 per sec and 100 per sec shows 

 that the degree of stimulation influenced the response to x-rays. Higher 

 frequencies of stimulation reduce the enhancement of spike amplitude, have 

 a slight effect on sensitivity, and have no observable effect on conduction 



