ACTION OF CURARA 1_ } .V) 



Sodium chloride. 

 Sodium iodide. 



Use great care in making the injections. Begin with 

 very small doses and inject more as the animal is able to 

 tolerate it. 



What conclusions can von draw with reference to the 



*/ 



diuretic action of these substances? How do they act? 



EXPERIMENT LIT. 



Curara. (Frog: General Action, Claud Bernard's 



Experiment.) 



1. Pith a frog (cerebrum only) and make a small incision 

 over the back of the right thigh (see Fig. 4-7). .Dissect up 

 a short length of the sciatic nerve. Do not cut or injure the 

 nerve. Pass a thread beneath the nerve and tie off the tis- 

 sues of the thigh tightly so as to completely stop all circula- 

 tion in the right (gastrocnemius) muscle and foot. With 

 single shocks stimulate the exposed nerve once or twice to 

 see how the muscles act in the isolated part of the leg. Also 

 stimulate the tissues at the back of the head over the upper 

 end of the cord once or twice to get the normal reactions. 

 Put a drop of acetic acid on the left hind foot and see if the 

 animal moves the limb. Brush off the acid. Count the rate 

 of lymph heart beats. 



Into the ventral lymph sac inject one cubic centimeter of 

 a saturated solution of curara. Wait three. minutes and 

 then begin to retest the reflexes from time to time as the 

 drug is absorbed. How is the rate of beat of the lymph 

 hearts affected? Will the animal jump when stimulated? 

 As the action of the drug becomes very marked stimulate 

 again the exposed sciatic nerve. (Keep the nerve moist with 

 salt solution where it is exposed.) Apply a drop of acetic 

 acid to the skin of the back. Is there any response? If so, 

 where ? Stimulate the upper end of the cord. What muscles 



