8 SEX-DETERMINATION 



genetic, theory was confirmed by the correlation that has 

 been observed between the distribution in inheritance of the 

 sex-chromosomes and of the sex-Hnked characters. Nothing 

 that has been encountered during the last fifty years has 

 required any significant modification of this theory. At 

 present it seems distinctly unlikely that this theory will be 

 at all seriously shaken in foreseeable time, but new dis- 

 covery in other scientific fields may, in its impact upon 

 biological science, necessitate its review and revision. 



