ON THE QUICK GROWING WALNUT 
compete with the dominant character. And 
whether in the end the new dominant character 
will prove itself and prevail, or whether the re- 
cessive character will re-establish itself, depends 
entirely on the value for the species of one char- 
acter as against the other. 
Mendelian heredity, then, is a_ testing out 
process for new characters. It is, as it were, the 
skirmish-line of the advance guard of evolution. 
So long as a character is subject to Mendelian 
transmission, showing the phenomena of domi- 
nance and recessiveness, it is a relatively new and 
unfixed character still on trial. 
And in proportion as any character has proved 
itself and has passed the trial stage, it becomes 
blended with the hereditary factors that have more 
stable position, just as conscious acts of the indi- 
vidual become instinctive or reflex when often 
enough repeated. 
In this view, then, the so-called unit characters 
that Mendelize are, as was said before, merely the 
fringe to the great fabric of heredity. They serve 
the plant developer an admirable purpose, and, 
indeed, it is with their manipulation that he is 
chiefly concerned. Their relative insignificance is 
evidenced in the fact that the plant developer 
cannot possibly produce major modifications in 
the organisms with which he deals. 
[225] 
