586 



C. S. BACHOFER 



/./ 



1.0 



0.9 



0.8 



0.7 



0.6 



0.5 



<»-<f-t3 



-o Lateral Fibers 

 -• Median Fibers 



10 



20 



30 



40 



50 



MINUTES OF X-IRRADIATION 



Fig. 10. Relative conduction velocity of giant nerve fibers of earthworm, plotted as 

 a function of time of x-irradiation, as in Fig. 8. (20 experiments). 



306 kr of x-rays. Figure 11, a composite graph in which the values obtained 

 from median and lateral fibers are combined, shows much the same pattern 

 as that observed in x-irradiation of mammalian nerve trunks. The refractory 

 period, not investigated in the experiments involving mammalian trunks, 

 showed a pattern of slight initial enhancement due to x-irradiation, followed 

 by a deterioration more rapid than that found in the other factors consid- 

 ered. Of particidar interest, in view of results to follow, is the fact that the 

 refractory period showed very slight enhancement. 



UV irradiation of giant fibers of earthworm. As in x-irradiation of giant 

 fibers of the earthworm, 90 minutes of stabilization preceded irradiation. 



