218 



EXPERIMENTAL PHARMACOLOGY 



reaction and it is important to record the first manifesta- 

 tions of this effect. The drum is kept running and pres- 

 ently further results will be obtained. When the first 

 round is completed lower the drum and take a second 

 round. Blow against the frog and note the results. How 

 do the contractions obtained on the first round compare 

 with those of the second! After the two rounds are coin- 



Fig. 208. Arrangement of frog and apparatus for recording the contractions of 

 the gastrocnemius muscle during convulsions. The animal's brain is destroyed. 



pleted dissect out the sciatic nerve on the back of the right 

 thigh (see Fig. 47, page 54) and cut the nerve in two. 

 Now stimulate the frog (blow against it) and note the re- 

 sults on your records. What does this show? What can 

 you say regarding the action of strychnine? Pass a soft 

 copper wire down the spinal canal and destroy the cord. 



