PHA RMA COL OGY. 289 



(<r) Why would you not use curare as an anaesthetic 

 if the poisoned animal does not react to painful 

 stimuli ? 



(5) Make two muscle nerve preparations as described 

 on page 56. Dip the nerve of one, and the muscle ol 

 the other into curare solution. The parts of the 

 preparations not immersed should be kept moist with 

 normal saline solution. After several minutes mount 

 specimens in the myograph. Stimulate the nerves 

 and note : 



(#) The relative reaction of gastrocnemii to indirect 

 stimulation. 



(b*) Does this bear a resemblance to any previous ex- 

 periment ? 



(V) How do results compare with those of previous 

 experiment? 



(6) Stimulate the sayne muscles directly. 

 (#) Relative reaction? 



(^) Taking this in connection with preceding experi- 

 ment, where have you proved that curare acts? 

 (V) How do experiments (5) and (6) compare with 



experiments (3) and (4) ? 



NOTE: Failure in experiments (5) and (6) may result 

 from insufficient immersion of muscle in curare solution, 

 capillary attraction resulting in curare reaching muscle 

 supposed to be free from poison, and drying of parts not 

 immersed in solution. Of thesethe first is by far the most fre- 

 quent cause of failure, the sheath of the muscle rendering 

 the absorption of poison a slow process. It may be over- 

 come by making a few slight incisions in sheath, or inject- 

 ing a drop of the curare solution directly into the muscle. 

 Failure of experiment (2), and consequently (3) and 

 (4), may result from ligature around thigh being not tight 

 enough to prevent diffusion of curare into gastrocriemius. 



