ACKROY/LEBGIffiNTS. 



Before entering upon the body of this presentation 

 I desire to express rny obligations to thoHe v/ithout v/hose co- 

 operation ny experinents would have been of less value. 



Above all r^rr. I indebted to Professor John E. \7atson, 

 Pirector of the Johns Hopkins Psychologicc.! Laboratory, who 

 has kept himself informed of the progress of my experimenta- 

 tion and who has been ready at all times with helpful suggest- 

 ions and encouragement. 



To Dr. Henry H. Ponaldson I owe much: for suggest- 

 ing the experiment; for placing the facilities and material 

 of the V.'istar Institute at my disposal; for much helpful ad- 

 vice as to the evaluation of my results. 



To Dr. Shinkishi Hatai for preparing the anatomical 

 data referring to the rats used in my experiments. 



To Dr. Helen D. King for keeping her sequences of 

 inbreeding moving so perfectly that, at any time, I was able 

 to procure inbred rats of the desired age. 



Gardner Cheney Easset. 



