FATIGUE IN NERVES. 



155 



ments. Fig. 7 illustrates the responses after 5 hours (3 stimulations in 

 between), and Fig. 8 after 25 hours (3 more stimulations). 



Fig. C. 



Fig. 7. 



Fig. 5. Upper line from cut root, lower from nerve in plexus. The upper lever was 

 raised at L. 



Fig. 6. Upper line from cut root, lower from corresponding cut nerve in pelvic plexus. 

 The contractions with V over are due to other causes than the stimulation. Crossed 

 reflexes are seen in both lines (marked A') and also an inhibition of tone (fall of lever 

 in lower line) on stimulation of opposite root. L change of level of lever. 



Fig. 7. Upper line from root, lower from nerve in plexus. V ' spontaneous ' contractions. 

 D = stoppage of drum, and L change in level of the lever. The momentary response 

 sometimes met with on stimulation of the afferent nerves is well shown, as it is also 

 in Fig. 6. 



It will be noticed the upper (cut) root gives a single small response 

 only. All the other contractions in the upper line marked X are crossed 

 reflexes. To make this clear the longer interval was allowed. The 

 uncut (ganglionated) root is still effective and remained so for another 

 24 hours, when the frog died, while the cut root gave only one more 

 twitch. During the first 6 hours of this experiment the two sides gave 

 practically the same total duration of movement, the numbers being 

 8 minutes for the cut root and 8^ for the ganglionated. On the next 

 day, however, the total amount for the cut root was only 1| minutes 

 during 3 hours when it ceased to give more contractions, while the 

 nerve had then given 4 minutes and as the tracing shows was still 

 effective. 



