ON THE QUICK GROWING WALNUT 
that “about one-third” of the second generation 
hybrids would revert toward one parent, while 
another third would revert toward the other 
parent, the remainder being intermediate in char- 
acter, and in this corresponding to the first genera- 
tion hybrid that was their parent. 
This implies a fair understanding of the com- 
bination of characters of the two parent species 
in the first generation hybrid, and the segregation 
and recombination of these characters in the sec- 
ond generation hybrid. It will be noted also that 
the distribution of these characters in the second 
generation (as predicted on the basis of my obser- 
vation of earlier seasons) was essentially that 
which has come to be familiar everywhere within 
recent years as the typical distribution of charac- 
ters among second generation hybrids in what is 
now known as Mendelian heredity. 
To be sure the figures given are only approxi- 
mate, nor have I in any of my experiments endeav- 
ored to keep accurate count of the precise 
numbers, the large scale on which I operate mak- 
ing this scarcely practicable—but the close approx- 
imation of the rough estimate that I made to the 
precise figures that have been determined by more 
recent investigations, sufficiently attests the accur- 
acy of the observations on which the estimate was 
based. 
[195] 
