ON THE QUICK GROWING WALNUT 
their hitherto harmonious coalitions, are reassorted 
in the second generation, as united groups acting 
along Mendelian lines, so that part of the progeny 
of the second generation are giants, and part of 
them are dwarfs, and that all manner of inter- 
mediate forms find recognition in the case of dif- 
ferent individuals. 
In no other way known to us could such a dis- 
turbance of the coalitions of hereditary factors 
have been brought about. So the plant developer 
who thus brings together racial strains that have 
been long separated introduces a disturbing ele- 
ment that in its practical effects may produce such 
modifications as could only be produced otherwise 
through the aggregate influences of environment 
for almost numberless generations. 
But let it be repeated that even when the 
hybridizer effects such a disturbance as this, he 
can do no more than to enable subordinated her- 
editary factors to make themselves manifest. 
He is dealing with material that has been 
brought together through age-long experiments, 
and even though the new combinations that he 
effects may be striking ones, he may rest assured 
that even his most spectacular achievement is but 
a feeble replica of plant developments with which 
nature has experimented thousands of times over 
in the course of the long evolutionary ages. 
[237] 
