SCOPE OF GENETICS 39 



of them of an unpaired factor. This conclu- 

 sion appears to me to follow so immediately 

 on all that we have learnt of genetic physio- 

 logy that with every confidence we may accept 

 it as representing the actual fact. 



The question which of the two sexes 

 contains the unpaired factor is less easy to 

 answer, but there are several converging lines 

 of evidence which point to the deduction that 

 in Vertebrates at least, and in some other 

 types, it is the female, and I feel little doubt 

 that we shall succeed in proving that in them 

 femaleness is a definite Mendelian factor 

 absent from the male and following the 

 ordinary Mendelian rules. 



Before showing you how the Sweet Pea 

 phenomenon aids in this inquiry I must tell 

 you of some other experimental results. The 

 first concerns the common currant moth, 

 Abraxas grossulariata. It has a definite 



