THE WHITE BLACKBERRY 349 



devised word "allelomorph," although the less 

 repellant equivalent "determiner" is gaining in 

 popularity. He calls the body substance of an 

 animal or plant a "zygote," and he describes an 

 individual that contains factors of a single kind, 

 as regards any pair of unit characters (say only 

 for blackness in the case of our blackberries or 

 Professor Castle's guinea pigs), as a "homo- 

 zygote"; contrariwise a body having both types 

 of factors (blackberries or guinea pigs of the 

 second generation, for example) as a "hetero- 

 zygote." 



But these big words, while it is convenient to 

 know their meaning, need not greatly concern 

 us. It suffices to recall the convenient terms 

 "dominant" and "recessive"; to recognize that a 

 good many antagonistic traits may be classed as 

 unit characters; and to welcome the conception 

 of the division of the factors or determiners of 

 such a pair of unit characters in the germ cell, as 

 enabling us to form a tangible picture of the 

 modus operandi through which the observed 

 phenomena of heredity may be brought about. 



MIXED HERITAGE OF THE BLACKBERRIES 



It remains to be said that the case of our black- 

 berries is a little more complex than the case 

 of the guinea pigs just referred to, because there 



