THE CHERRY 133 



four, one BE individual, two Bb individuals, and 

 one bb individual. Being interpreted in terms 

 of our actual row of seedlings, as they stand in 

 our orchard in this, the fourth or fifth year of our 

 experiment, this means that in every lot of four 

 thousand seedlings one thousand are pure domi- 

 nants as regards large fruit, two thousand are 

 mixed dominants, and one thousand are pure re- 

 cessives, if we do not take into consideration the 

 fact of past mixed hereditary tendencies. 



But now comes a very tangible and very prac- 

 tical complication. As regards their external 

 traits, and as regards the fruit that they will 

 individually bear, the one thousand pure domi- 

 nants (BB) and the two thousand mixed domi- 

 nants (Bb) are identical. There is nothing in 

 their exterior appearance, and there will be 

 nothing in the appearance of their fruit, to indi- 

 cate which of them contain only the factors of 

 dominance (BB), and which contain the recessive 

 factor combined with the other (Bb). Yet for 

 the purpose of future experimentation, in which 

 we shall be obliged to call on succeeding genera- 

 tions, theoretically it makes a vast difference 

 which individuals are selected. 



We are well aware of this as we walk along 

 the row of our seedlings, but we are also aware 

 that there is no method by which we can fathom 



