ACTION OF PILOCARPINE AND ATROPINE 277 



tion of this drug on the heart and circulation? Is there 

 any action on the glands? Be sure no atropine gets into 

 the vein until you are entirely ready for it. 



When the animal recovers inject more pilocarpine. Be 

 sure you get in enough to bring out the action of the drug 

 well. The animal is not likely to die early if small doses 

 are used. Note the action on the pupils, salivary glands 

 and pancreas. How do you explain this? Inject one-half 

 cubic centimeter of adrenaline and see how this counter- 

 acts the action of the pilocarpine. Examine the pads of the 

 feet and see if any small sweat drops are forming. (Ke- 

 member the circulatory disturbance you have caused in the 

 hind limbs.) Inject more pilocarpine and try to get as 

 marked action on the heart as possible. In a good typical 

 case a long series of carotid tracings may be obtained in 

 which separate heart beats may have an amplitude of from 

 one-half up to three-fourths of an inch. When this stage 

 is reached quickly observe the rate of salivary and pan- 

 creatic secretion and then inject one cubic centimeter of 

 atropine. This will not reach the heart for some time. 

 Wait and see what happens. Explain all results observed. 

 On what structures does each drug act? If necessary in- 

 ject one cubic centimeter more of atropine. Now inject 

 one-half cubic centimeter of adrenaline to restore the ani- 

 mal. Stimulate the chorda tympani and the vagi. What 

 effect has this on the salivary or pancreatic secretion? 

 How does the vagus stimulation affect the heart, blood- 

 pressure, and respiration? 



Observe carefully your record of respiration just after 

 the pilocarpine was first injected. Is there a peculiar de- 

 crease in amplitude with some difficulty in either expira- 

 tion or inspiration? "What possible explanation can you 

 offer for this? How did the atropine affect it? 



Inject one cubic centimeter more of pilocarpine. Is the 

 heart slowed? On what structures does atropine antago- 

 nize the action of pilocarpine? What is the action of pilo- 



