54 RUTLEDGE T. WILTBANK 



The trial-groups all effected a large saving in the first 

 three trials upon the resumption of the E maze. It may 

 be said, in other words, that while they were learning 

 the D maze following their two, four, eight or sixteen 

 trials on E, they were continuing the learning of E, for 

 on their return they showed both an improvement up- 

 on their earlier performances in E and a marked saving 

 as compared with the control-group. Even more, some 

 of the rats on their return to E ran that maze four times 

 in succession without an error. Of those whose learning 

 had been interrupted after two trials, three out of the 

 seven rats composing the group made a perfect score upon 

 their return to E, and none of these three had made an 

 errorless run on either of their two former trials in E. 

 Of those whose learning had been interrupted after four 

 trials, one rat out of seven made a perfect score, so far as 

 errors were concerned, and another made but one error 

 in five trials; and neither of these had made an errorless 

 run in its four previous trials. Of those whose learning 

 had been interrupted after eight trials, six out of ten made 

 a perfect score, and one made a single error in five trials; 

 and among these was one rat which had made one errorless 

 run, which was its first trial, and another which had made 

 two errorless runs, on its fifth and sixth trials respectively. 

 Of those interrupted after the sixteenth trial, two out 

 of eight made a perfect score, one of these having made 

 one errorless run, on its second trial, and the other no 

 errorless runs. 



If the general statement is justified that, while the rats 

 of all four groups were learning D after having begun to 

 learn E, they were continuing their learning of E at the 

 same time they were learning D, there is equal justifi- 

 cation for the statement that certain of these rats while 

 being taught D completed their learning of E. It would 

 be tempting to believe that these rats making errorless 

 runs on their return to E had learned to recognize a blind 

 alley at sight, if both their behavior in the maze and also 

 the results of the experiments which have been made 

 upon the rats' sensory control in the maze did not preclude 

 such a belief. The present experiment does not furnish 



