BURBANK PLUMS 



precisely alike, any more than any one of them 

 would be precisely like any individual ancestor. 



In a word, then, it seemed obvious to me that 

 the individuals of a species constitute a variable 

 and plastic race, in virtue of their diversified an- 

 cestral strains. 



And if such variations are the natural result 

 of the operation of the laws of heredity when 

 closely similar individuals, ranked as of the same 

 kind or species, are mated, it seemed reasonable 

 to expect that still wider divergences and diver- 

 sities must be brought about in the offspring of a 

 union between individuals so conspicuously dis- 

 similar as to be ranked as members of different 

 species. 



Part of this, to be sure, was matter of com- 

 mon knowledge; for certain examples of the 

 hybridizing of species in the animal world has 

 long been familiar, the case of the mule being 

 perhaps the most striking one under everyday 

 observation. But this particular case illustrates 

 the union of species that have become so widely 

 divergent that nature appears to put a ban upon 

 their union; permitting, indeed, the birth of off- 

 spring, but condemning the offspring to infer- 

 tility. The inference that this case typifies the 

 result of the interbreeding of species is utterly 

 misleading. 



