58S 



C. S. BACHOFER 



1.3 



1.2 



1.0 



0.9 



0.8 



0.7 



- »—<»—' 



-o Median Fibers 

 ■• Lateral Fibers 



Beginr)ing of 

 UV Irradiation 



A/Ao =0.01 

 at 114 min. 



A/Ao = 0.03 

 at 116 min. 



20 



40 



60 



80 



100 



MINUTES 



Fig. 12. Relative sensitivity to electrical stimulation during UV irradiation of giant 

 nerve fibers of earthworm, plotted as a function of time of irradiation. Dose rate: 

 7,200 ergs per cm" per sec. 



tive amplitude of the spike and the corresponding relative rate of spike rise 

 are shown in Fig. 15. From the beginning of irradiation there was an obvious 

 downward drift in the rate of spike rise, indicated by the dotted line, on 

 which was superimposed a secondary rise corresponding for the most part 

 to the increase in amplitude. This analysis of the rate of spike rise as a 

 function of amplitude of action potential shows that the highest spikes 

 tended to accompany the highest rates of voltage change. 



Figure 16 shows the results of UV irradiation on refractory period in 

 three sets of experiments. Only a part of the preirradiation period is shown 



