220 COMPARATIVE PHYSIOLOGY OF THE BRAIN 



morphisms which have characterised this field here- 

 tofore (4). But I am afraid that he went too far 

 and that he overlooked the fact that bees and ants 

 possess associative memory. Bethe assumes associa- 

 tive memory as the criterion for the existence of con- 

 sciousness, as I had done before. (He has evidently 

 overlooked, or at least does not mention, my work on 

 this subject.) According to him : " An animal that 

 is able to do the same things the first day of its exist- 

 ence which it can do at the end of its life, that learns 

 nothing, that always reacts in the same way upon 

 the same stimulus, possesses no consciousness." This 

 statement is not sufficient. It is possible that an ani- 

 mal at birth, or just after hatching, may not be fully 

 developed. In this case it may be able later to per- 

 form actions which would have been impossible 

 on the first day, without possessing associative mem- 

 ory. Yet according to Bethe's definition such actions 

 would indicate associative memory. 



It is a well-known fact that if an ant be removed 

 from a nest and afterwards put back it will not be 

 attacked, while almost invariably an ant belonging to 

 another nest will be attacked. It has been customary 

 to use the words memory, enmity, friendship, in de- 

 scribing this fact. Now Bethe made the following 

 experiment. An ant was placed in the liquids (blood 

 and lymph) squeezed out from the bodies of nest 

 companions and was then put back into its nest ; it 

 was not attacked. It was then put in the juice taken 

 from the inmates of a " hostile " nest and was at once 



