IMPROVING SMALL FRUITS 68 



"Whoever heard of a white blackberry?" de- 

 mands B, turning thus rather neatly the argu- 

 ment that the other elf used about the thorns. 

 "The thing is ridiculous/' 



"I represent a white blackberry,'' A replies, 

 let us hope with dignity. 



"Well, there isn't any way of blending white 

 paint and black and keeping things white, is 

 there?" B continues. And this argument is con- 

 clusive. The two color factors are assembled, 

 and it is conceded that the future plant will bear 

 black fruit. The black pigment overlies the 

 white like a double coat of paint, and a black 

 fruit is provided for. 



When the elfin architects have finished their 

 task, then the factors representing the materials 

 of the two germ cells have all been satisfactorily 

 paired, and provision has been made for a future 

 bramble that will have a thorny stem and will 

 bear black berries — a plant that is unlike either 

 parent, although built of no material except 

 factors drawn from the two parents. 



Recall, however, that the factors for thornless- 

 ness and for white fruit were not eliminated. 

 They were only overlaid by the opposing factors. 

 They go forward in the germ plasm, each pair 

 of factors being constantly multiplied through 

 division in the mysterious way that characterizes 



