How FAR CAN PLANT 
IMPROVEMENT GO? 
THE CROSSROADS—-WHERE FACT 
AND THEORY SEEM TO PART 
HEN I first began this work,” said 
Mr. Burbank, “I was taught that a 
combination between two varieties of 
the same species was possible—that I might cross 
one plum with another plum, for example, to get 
a new variety—but that the species marked the 
definite boundary within which I might work. 
The science of that day was firm in its belief that 
a seed-bearing, self-reproductive cross between 
plants of different species was beyond the pale of 
possibility. 
“A little later on, when I succeeded in com- 
bining the plum with the apricot, and produced, 
thereby, a new fruit whose parents were of 
undeniably different species, the law, or rule, was 
moved up a peg; and I was fold that while it 
might be possible to effect combinations between 
different species, yet that must be the limit of 
[| VoLUME I—CxuHaprter VII] 
