HEREDITY. 27 



our protest against the too prevalent custom of denoting genes 

 which have a similar effect by similar symbols. If three genes 

 all tend to make the colour of a flower lighter, we do not think 

 it better to denote them by L lt L 2 , L 3 , than to use the symbols 

 A, B and C for them. Physiologically, or biomechanically, there 

 may be a very great difference in the way in which the pres- 

 ence of these genes tend to lighten the colour. Using the 

 denotation L x L 2 L 3 heightens the impression that somehow 

 these genes are components of one thing, that they have, at 

 some former period, constitued one single gene. 



