254 EXPERIMENTAL PHYSIOLOGY. 



The operation should be performed at least two or three hours 

 before the observations are to be made in order to permit complete 

 recovery from the ether. 



A decerebrate pigeon has no memory, therefore no sense of fear. 

 Tt is not conscious of painful stimulation. It sleeps unless stimu- 

 lated. It starves unless food is placed back in the throat so that 

 the swallowing reflex is started. 



Stimulate the pigeon in the following ways : 



1. Push it in order to get it to move. 



2. Produce a loud sharp sound near one ear. 



3. Allow it to smell strong ammonia. 



4. Stand it on a sheet of metal and gradually heat the latter 

 until too warm for your own hand. 



5. If the bird is not too weak, toss it into the air and it should 

 fly. 



Make notes of the behaviour of the animal in response to these 

 stimuli and explain the results. 



