THE PROBLEM OF LEARNING 1 83 



propriately within a few hours after its removal. 

 As the brain regenerates, the worm exhibits in- 

 creased initiative, its behavior becomes less auto- 

 matic, more variable. Two months after the 

 removal of the 'brain,' during the last four weeks 

 of which period no training was given, the habits 

 had completely disappeared. Systematic training 

 of two weeks resulted in the partial reacquisition 

 of the original direction habit. The various facts 

 recorded in this investigation indicate that the re- 

 moval and the regeneration of the first five seg- 

 ments resulted in the development of a worm 

 strikingly different in behavior from the original 

 worm." * 



Before indicating the significance of this 

 method of training, we must examine the methods 

 employed in one of the lower vertebrates, the com- 

 mon frogs t and the racoon, one of the mammals. 



Frogs are like toads in their method of captur- 

 ing food. The tongue covered with a sticky 

 mucous is quickly thrown out striking the passing 

 insect which is captured just as a fly is caught when 

 it alights on fly-paper. Schafler constructed a 

 cage with natural conditions such as water, stones, 

 moss, etc., closely imitating the environment of 

 the animals to be experimented on. The common 



*Yerkes: The Intelligence of Earthworms, Jour. Animal Be- 

 havior, 1912, No. 5, Vol. II. 



tSchaffer: Habit Formation in Frogs, Journal Animal Re- 

 havior, 191 1, Vol. I. 



