230 EXPERIMENTAL PHARMACOLOGY 



does this affect the convulsions, blood-pressure, respiration 

 and oxygen consumption! Inject more chloral from time 

 to time and observe its general action as fully as you can. 

 If the animal is still alive empty the chloral out of the 

 burette, then take the burette out of the clamp and place 

 the upper end of the empty burette in your mouth. Take 

 the bull-dog off the femoral vein and blow some air into 

 the vein. Replace the bull dog and watch the action of 

 the air on the animal. What is meant by air embolism ? 

 How may it be produced? How does it act inside the 

 heart chambers'? In the vessels? Blow more air into 

 the vein if necessary to kill the animal. What conclu- 

 sions can you draw from this? 



Caution. The alimentary canal of the dog contains large numbers of tape 

 worms and ilieir eggs. If these eggs are swallowed by other animals infection 

 may occur. 



If time permits, dissect out the nerves to the bladder 

 (and uterus if the animal is a female). 



EXPERIMENT XXXVI. 

 Strychnine. (Student: Reaction Time.) 



1. Test the acuteness of hearing of the student who is 

 to act as the subject of the experiment. Do this by allow- 

 ing the student to sit at a table (at complete rest) with his 

 ear or the side of his head against a heavy stand (which 

 must not be moved later). A watch is now moved away 

 from the ear of the subject until the ticking can just be 

 heard (note the position of the watch, i.e., which side is 

 toward the subject). Mark this distance on the table or 

 otherwise and then take the watch back to the point 

 where the ticking just fails to be heard. Mark this point. 



2. Xow refer to the arrangement of the apparatus 

 shown in Figs. 134 and 137 (also see Experiment XIII, 1, 



