ACTION OF STRYCHNINE 



22J 



canal. Arrange for taking heart tracings. Dissect out 

 the vagus nerve in the neck (Fig. 70) and record a nor- 

 mal inhibition at two places in the lower round on the 

 drum. Lower the drum and start a second round. Apply 

 strychnine solution (one cubic centimeter equals one milli- 



frr gating fluid 



Requlatina 

 screw clamp 



Fig. 210. Greene's method of irrigating the heart. 



gram) to the heart with a medicine dropper or according 

 to Greene's method (Fig. 210) for irrigating the heart. Do 

 you notice any immediate change in the appearance of the 

 heart beat? Might this be due simply to the fluid moisten- 

 ing the heart muscle (as normal salt solution would do) or 



