278 HARVEY CARR 



were subjected to the ' variable route ' test and none were 

 affected. Five blinds were tested on variations of method of 

 handling without disturbing results. Two blinds were sub- 

 jected to the first test on uncovering the maze and no effect 

 was noticeable. 



3. In the third class 'fall those experiments in which both 

 blind and seeing rats were tested, but in which the disturbance 

 was limited to those animals with vision. 



Alterations in the position of the experimenter affected none 

 of the five blind animals tested, while every member of a group 

 of six normal rats was disturbed. 



A change in the position of the maze had no effect upon any 

 member of a group of five blind animals. In a group of six 

 normal rats, four were affected and these made an average 

 error record of 2.08. 



4. In the remaining experiments, both blind and normal 

 animals were tested and both groups were disturbed. The 

 comparative records will need to be stated in detail for each 

 experiment. 



Degree of Hunger. Two blind rats were compared with ten 

 normals. All members of both groups were disturbed. The 

 blinds made errors the more frequently; the percentages of 

 trials with error being 42 and 34 respectively for the blind and 

 visual groups. The average error records for the two groups 

 were 9.75 and 2.38 for the blinds and normals respectively. 

 The blinds manifested their maximum of disturbance on the 

 third trial while the normals gave the largest error record on 

 the fifth trial. The blinds also exhibited the greater error 

 record on a return to normal conditions. 



Cleansing Maze. Seven blinds were compared with ten nor- 

 mals. Fewer blinds were affected, the percentages being 57 

 and 80. They made errors in 75% of their trials as compared 

 with 61% for the normals. Their average error record was 

 6.00 as compared with 1.70 for the normals. Their greatest 

 disturbance occurred on the first trial while the normals made 

 their poorest record on the second trial. The time necessary 

 to effect an adaptation was the same for the two groups. The 

 blind animals exhibited the greater range of variability as to 

 number of errors per rat; the average and the average varia- 

 tion for the blinds were 24.0 and 18.6 respectively, while the 



