GENERAL PHYSIOLOGY. 



69 



(c) Vary the experiment by the use of the ascending 

 current. 



(3) (a) Increase further the strength of the stimulus by 

 the use of a battery of three or four cells. 



Record effect of descending current, 

 (b) Record effect of ascending current. 



(4) Set up electrical apparatus with simple rheocord as 

 shown in PI. II. Fig. 7. Instead of making a tracing 

 tabulate the results. 



(a) Adjust for stimulation with the minimum descend- 

 ing current. Make the muscle circuit and record 

 whether the muscle contracted, or remained at rest. 



(b) Stimulate with minimum ascending current and 

 record. 



(c) Gradually strengthen the current, recording at 

 each position of the slider the results for both de- 

 scending and ascending currents, make and break. 



The following form of table should be used: 



(5) Sum up the day's work in a series of conclusions. 



