ACKNOWLEDGMExNT 



The experiments herein described were carried on under the 

 general direction of Professor John B. Watson of the Johns 

 Hopkins University, who has been unsparing in suggestion, 

 assistance and criticism. Professor Knight Dunlap has ren- 

 dered valuable criticism as to method and apparatus. Dr. 

 Adolf Meyer furnished the two animals used throughout the 

 experiments in audition and in a part of the work described 

 in part two. Professors Angell and Carr placed the facilities of 

 the laboratory of the University of Chicago at my disposal in 

 the summer of 1911, at no small inconvenience to themselves. 

 Dr. Walter E. Dandy, Dr. Conrad Jacobson and Dr. Henry 

 Dick very kindly performed some necessary operations and 

 furnished other aid. 



