180 STELLA B. VINCENT 



trial and in the last five trials but looking at the average number 

 of errors for the first five trials and the total errors per animal 

 we see that the balance is in favor of X maze. 



Thus the error balance in the figures of the two mazes now 

 leans to one side and now to the other. These differences, also, 

 probably spring from the form and character of the cut de sacs. 



The lower final speed in the X maze is caused by one slow 

 animal. If we take the time for all of the runs in which there 

 were no errors in both series and from these records compute 

 the speed per foot for each maze we find it to be exactly the 

 same, 2.5 feet per second. This is not the final speed, however. 



The object here is not to go over these details item by item 

 but merely to show that, in general, these mazes are alike in 

 type and the reactions made in them are therefore approximate. 



COMPARISON OF EXPERIMENTS ON X AND Y MAZES 



We will now turn to a consideration of the experimentation 

 on the X maze, where the sides to the runways were on, and 

 the same maze, which we will call the Y maze, the open maze, 

 where the runways had no sides. 



The behavior in the X maze needs no description but that 

 in the Y maze showed essential differences. When the sides 

 were taken from the runways and the rats put on the maze 

 they showed a marked tendency to follow the edges of the 

 paths. They did this either by turning their vibrissae down 

 against the sides or by curling their toes over the edges of the 

 board. That this was a real control was shown by using rats 

 whose vibrissae had been cut on one or both sides of the head, 

 by using blind rats with and without vibrissae and rats in which 

 the branch of the fifth nerve which innervates the upper lip 

 and snout had been cut. The learning in all of these cases was 

 made more difficult except in one instance. In this case the 

 vibrissae were cut on one side only. As a result, the animals 

 were forced to keep to one side of the maze and by following this 

 side they made their way around the labyrinth almost imme- 

 diately. It is impossible here to go into all of the evidence and 

 readers are referred to the original monograph. 12 The work 

 conclusively showed that the tactual-cutaneous experience had 



12 Op. cit. 



