BEHAVIOR OF VERTEBRATES 447 



behavior of No. i is closely observed and recorded. The beha- 

 vior of No. 2 will rarely be identical repetition. We may be 

 fairly certain, then, that No. i will have furnished to him by 

 No. 2 or vice versa, an example or act to imitate." 



Porter states that he found satisfactory evidence of the pres- 

 ence of imitation in most of the birds tested except the blue 

 jays. There was some evidence that members of the same 

 .species imitate each other more closely than members of differ- 

 ent species. 



HABIT FORMATION 



Mammals. Glaser '^° succeeded in obtaining the rapid for- 

 mation of habits in the white rat by a rather ingenious method. 

 A zinc tank about two feet square and six inches deep was 

 covered with coarse wire netting and filled with water. A cir- 

 cular opening was made in the center of the wire gauze and 

 fitted with a cylindrical shoot. Each of the four corners of the 

 cover was supplied with a small opening covered with a hinged 

 door. Any one of these openings, at will, could be made the 

 true exit from the maze. The time record of the escape from 

 the labyrinth was taken and a plot made of the animal's path. 

 In addition to the data obtained upon habit formation under 

 these novel conditions interesting comparisons are made between 

 the adults and the young with respect to the rapidity of habit 

 formation. The facts obtained on the rat's use of its senses in 

 the maze support in the main the work of other investigators. 



