No. G43] STUDIES ON THE DURATION OF LIFE 



181 



days from generation to geiici'al inn in ili,. ra^c of iv- 

 prodiicing freely at random in >i(.ck Imtil,'^. ih.. int"i-\al 

 elapsing between the first and scfond tc-t^ w.mld cdvci- 

 roughly almost 18 generations. Tliis is a pnin,! 

 and affords abmidant opportunity for change in the a\ t r 

 age genetic constitution of the population. 



An examination ol' Tables \' and \'l and I-'iu'. - .-hows at 

 once, in a general wa\", that the c'liai'a('teri>iic feaTurt s of 

 the several lines in resjxer ol' dui-atidii «>r life did in fact 

 hold remarkably constant dni-iim- this pt'riod. A ni(»r(^ 

 precise comparison of the niean> i> made in Tahlc 



