38 journal of Comparative Neurology and Psychology. 



efficiency of these two possible modes of stimulation in determin- 

 ing the rats' behavior at the turns. If the animals run at full 

 speed against the ends of the shortened alleys at /, //, /Fand V, 

 evidently the assumption that they receive extraorganic stimu- 

 lation there of functional value to them is most improbable. If 

 the rats succeed in making the turns as correctly as usual, we 

 must conclude that such conduct is determined wholly by extra- 

 organic stimulations and is not influenced effectively by kinaes- 

 thetic ones. The experiment is decisive in estimating the relative 

 efficiency of the two possible modes of stimulation, because it 

 brings them into functional opposition. 



The results obtained from this experiment justify our assump- 

 tion that the turns are made in response to differences lying in 

 the kinaesthetic impulses themselves. Marked disturbances of 

 conduct were noticed in every rat. On the average sixteen trials 

 per rat were necessary wholly to eliminate these disturbances, ;. ^., 

 to secure accurate, automatic adjustment to the shortened maze. 

 Rats can often learn a maze of this complexity de novo in this 

 number of trials. This fact is evidence of the profound disturb- 

 ances eff^ected by the change. 



The time for running the maze was increased despite the short- 

 ened length. The increase of time was hardly proportionate to 

 the degree of disturbance as reflected in the nature of their be- 

 havior. Table I gives the avera'ge time in fractions of a minute. 

 The normal time for running the maze in its shortened form was 

 secured by averaging many individual records of trips made after 

 the reactions of the animals had become thoroughly automatic. 

 The records of the seven animals made after the maze was short- 

 ened were averaged for each trial. The time increases for the 

 first trials, and then gradually decreases toward the norm. 



The disturbances consisted of (i) running squarely into the 

 ends of the alleys at /, //, ///, IV and V:, (2) errors, such as par- 

 tial returns or entering into some of the cul-de-sacs; (3) slow, 

 hesitant and careful movements; (4) stopping here and there and 

 "nosing" around the sides of the alleys, and (5) compensatory 

 adjustments. By the last phrase, we refer to the fact that, after 

 running into the end of an alley for several trials, the rats often 

 attempted to make that turn too soon and would come in contact 

 with the inner corner of the turn. This tendency was most evi- 

 dent at IV. The alley IV in the shortened maze occupies the 



