280 



EXPERIMENTAL PHARMACOLOGY 



this? Wait for the action of the drug to become well de- 

 veloped. If you are sure the dose was too small then inject 

 a second (but one cubic centimeter is usually sufficient for 



Fig. 247. Tracing showing the action of barium, adrenaline and atropine on the 

 blood-pressure and intestinal contractions in a dog. The barium had been given just 

 before this tracing begins. Its action on the intestine is quite evident but the contrac- 

 tions are checked, first by adrenaline (which stimulates the inhibitory endings) and. 

 second by atropine. How do you explain this latter action? 



