154 



F. H. SCOTT. 



During the first three hours of this experiment the total duration of 

 movement from the severed root aggregated 37f minutes, and from the 

 unsevered 38 minutes. On the next day the numbers were 31| minutes 

 for the severed, and 40^ for the unsevered, while on the following day a 

 few twitches, aggregating about \ minute, were obtained from the 



Fig. 3. Fig. 4. 



Fig. 3. Upper line from cut root, lower from corresponding nerve in plexus. The 



numbers in the signal line indicate seconds. At end stimulation every 10 seconds. 



Fig. 4. Upper line from cut root, lower from nerve in plexus. Stimulation 1 minute, 



30 seconds and 20 seconds. The L indicates a change of level of lever. 



severed, and the unsevered gave 3f minutes at that time, and was still 

 effective afterwards, as the figure shows. 



One does not usually get numbers so large as those in the above 

 experiment, the total of 69 minutes being the greatest observed for a 

 cut root. As before stated it is usual to obtain about 15-40 minutes 

 from the cut root. Figures 6, 7, and 8 are from a frog which did not 

 yield even that amount because most of the time the responses were 

 little better than simple contractions. Fig. 6 is the first series obtained 

 and illustrates the irregularity often met with at first. The contractions 

 with a V over them are spontaneous, caused by some other irritation 

 than the stimulation. The commencement of the lower line illustrates 

 a phenomenon sometimes seen, namely, an inhibition of tone on stimula- 

 tion of the opposite root. Both lines contain a number of crossed 

 reflexes. These are marked in the tracings by a cross. Owing to 

 a slight misplacement the lower two levers were not exactly under the 

 upper two but the stimulation was alternating as in the other experi- 



