FATIGUE IN NERVES. 



153 



the commencement of the experiment. Both sides are seen to be 

 practically identical, and the gradual loss of power is well seen. This 

 gradual loss of power is a typical feature, although often not as 

 regularly shown. Figs. 2, 3, 4, and 5 are parts of the record of the 



Fig. 2. Upper line from cut root, lower line from corresponding cut nerve in plexus. 

 Time of stimulation 30 seconds or twice (in middle) 1 minute. 



same frog. This frog had the greatest resistance to fatigue and the 

 greatest power of recovery of any frog met with. Fig. 2 is the first 

 tracing, finished, as the number above indicates, at 2.41 in the afternoon. 

 It was stimulated twice more during the afternoon, and once the next 

 morning before Fig. 3 was obtained. It will be seen that the lower one 

 (ganglionated) gives more prolonged contractions, although its power of 

 recovery at the end to rapidly repeated stimuli (every 10 sec.) is slightly 

 less than the one without the ganglion. One more series of stimula- 

 tions, in which the ganglionated root was much the better, was made 

 before Fig. 4 was obtained at 12.02 that is 22 hours after the 

 commencement of the experiment. It is now seen that the lower one 

 is undoubtedly the better, and it remained so till the end. The cut 

 root gave a little more response during the afternoon and a few twitches 

 the next morning, when it finally failed. Fig. 5 is a piece of tracing 

 taken 48 hours after the commencement of the experiment. It is seen 

 that the severed root is inactive, while the unsevered root gives fair 

 responses. 



105 



