298 



RAYMOND PEARL 



ments with mice, and nature's experiments with the working- 

 men's population studied statistically by Elderton and Pearson. 

 The experiments here reported are being continued. 



XIII. APPENDIX 



In this appendix are given the frequency distributions of the 

 growth measurements, on which the constants of tables 11, 12, 

 and 13 in the text are based. 



TABLE I 

 Untreated cfcf X untreated ? 9 . Ages: 2 days and 5.5 days 



