28 JOSEPH PETERSON 



and take note of external stimuli, but resembled automatic 

 machines in the quickness and uniformity of their responses. 

 This change appears more significantly in the results of most 

 of the individuals than in those of all averaged. Here are some 

 examples. Rat 18, of Group Mw made entrances to the first 

 bhnd alley (full length) in this order: 12c (complete), Ih (half), 

 Ic, Ih, 5c, Is (started), 4c, Ih, 2c, Ih, 5c, Ih, 4c, Ih, Ic, 4h, 

 2c, 3h, 3s, Ic, Ih (total 55 entrances). Rat lO's record, same 

 group, is Is, Ic, Ih, 9c, Ih, 7c, 2h, 3c, Ih, Ic, 2h, Is, 2c, Is, 2c, 

 Ih, Is, Ic, Ih, 2c, Ih, Ic, Ih, Ic, Ih, Ic, 3h, Is, Ic; the next time 

 on passing this cid de sac there was a momentary pause with 

 three very rapid in and forward vibrations of the head, causing 

 a confusion in which the animal made eleven errors in the other 

 nine citl de sacs none of which it had entered, with but one 

 exception, for twelve trials; then Is, 2c, Is, 2c (after another 

 such vibrating pause before the cul de sac), 2s, Ic, Ih, Is, 2c, 

 Ih, Ic, Ih, Ic, Is (total 70 entrances). These results are typical. 

 In numerous cases when the habit of avoiding the cul de sac 

 was nearly complete, so that the animal usually made the " s " 

 type of entrance, the peculiar rapid vibration of the head noted 

 above took place. The pause was, however, but for an instant. 

 This response seems to indicate that the impulse to go forward 

 at the critical place is still partly checked or impeded l:)y one 

 to enter, not quite eliminated. It is important to note, more- 

 over, that when finally the rat does succeed in passing the cid 

 de sac, even when this hesitant, vibrating behavior does not 

 take place, it very frequently runs headlong into some neighbor- 

 ing cul de sac which had long since been inhil:)ited, and thereby 

 gets considerably confused. Frequently, after such an experience 

 it makes a complete entrance into the cul de sac in question the 

 next trial, just as a child " speaking a piece " must bow again 

 and start over when she goes wrong. This is one reason why 

 a few complete entrances continue to occur. More than once 

 an animal which had successfully passed cid de sac 1 for several 

 trials would, without any hesitancy, run into it with great speed 

 and against the closed end with terrific impact. In one such 

 case the animal's whole maze habit, just on the finishing stage, 

 seemed to have been temporarily jolted wholly out of gear, its 

 next trial being much like that of a beginner. All this makes 

 it very plain that maze habits are not to be explained on the 



