ACTION OF CURARA 257 



EXPERIMENT LIIL 



Curara. (Frog: Heart and Vago-sympathetic Nerve.) 



1. Pith a frog and arrange to take a heart tracing. 

 Stimulate the vagus nerve and get a normal inhibition. 

 Drop on the heart a few drops of a saturated curara solu- 

 tion. What do you observe? Now stimulate the nerve 

 again and record the result. Has any change been pro- 

 duced! If not apply more curara and stimulate again. 

 Now stimulate the crescent and record the result. What 

 do you observe ? How do you explain this f Apply more of 

 the drug to bring out the later action on the heart. 



EXPERIMENT LIV. 



Curara. (Turtle: Heart and Vagus Nerve.) 



1. Repeat the above experiment on a pithed turtle. 

 How do the results obtained with this animal compare with 

 those from the frog? What is the innervation of the tur- 

 tle's heart? How does it differ from that of the frog? 



EXPERIMENT LV. 



Curara, Strychnine. (Dog or Cat: Blood-pressure, Respi- 

 ration, Urine, Sciatic Nerve. Dog: Salivary 

 Ducts and Nerves.) 



1. Weigh a medium-sized dog and give it by stomach 

 three hundred milligrams of chloretone per kilo of body 

 weight. Dissolve the chloretone in ten cubic centimeters of 

 alcohol (absolute) and dilute the solution as much as pos- 

 sible with water. Add a little alcohol to redissolve any pre- 

 cipitate formed. After ten minutes etherize the animal and 

 attach it to the operating board. Arrange to record blood- 

 pressure and respiration (stethograph). The injecting bu- 



