CONTENTS 



PAGE 



INTRODUCTION 1 



MATERIAL AND METHODS 2 



EXPERIMENTAL RESULTS 14 



A. General comparison of inheritance in the hybrid generations of both 



series 14 



B. Effect of age, frequency and number of tests on the lowering of the 



grade of wildness and savageness in the successive tests 23 



C. Results from crossing wild females with tame males in comparison 



with results from crosses of tame females with wild males' 38 



D. General summary of individual inheritance and the results of selec- 



tive breeding in the hybrid generations of both series 45 



OBSERVATIONS ON "SINGING" IN MICE 63 



SUMMARY AND CONCLUSIONS 66 



BIBLIOGRAPHY -. 68 



The writer wishes to acknowledge his indebtedness to Professor Robert M. 

 Yerkes, without whose valuable suggestions and aid this study would not have 

 been possible, and to Viola Hunter Coburn for assistance in the compilation of 

 the tables. 



