658 CANNON: A CYTOLOGICAL Basis 
with A characters are fertilized with other plants with the same 
characters, that is to say, if inbred, two sorts of hybrids will result : 
one portion will bear only the A characters, which may be demon- 
strated by inbreeding as before, and one portion, apparently also 
with 4 characters only, will be found to vary just as the hybrids 
of the primary cross varied, 7. ¢., this portion is really mixed or 
hybrid. The hybrids that bear the a characters are known as the 
“‘recessives” ; they do not appear in the first generation, and those 
with the A characters are called the “ dominants,”’ and they mask 
in the first generation the recessives. This general scheme may 
be better understood if tabulated as follows : 
Generations T ll , Ul iv 
Halide € BE ib scacd) seuenas thers G ccbcedgsansesave qeLicecccvevnccccves® ete. 
(male or : 
female). , 
TE. i csidevevessese YB SET: ele. 
4 
24 (a)... 
oe SA se 
3 
2 PA ests ervecsse Ao ee ete 
| [ 
naa 1A pe pe cstate pe en A, cee ett. 
(male or 
female). 
Fic 1. Explanation: 4: dominant character; @: recessive character ; A (a) 
a hybrid having both characters of which (a) is masked by 4. 
Not only do the hybrids vary thus in a regular manner but 
there is also a definite proportion of recessives (a), and dominants 
(A), as the table indicates. That is, referring to the table, in the 
second generation one fourth of the offspring is recessive (2), and 
three fourths apparently dominant (A) only, but really composed 4 
of the two sorts (A(a)) one third of these being dominant (pure), 
and two thirds mixed (A(a)). The latter continue in the succeed- 
_ ing generation to vary just as the hybrids of the primary cross 
varied, 7. ¢., one fourth of their offspring bearing recessive, see 
ee fourth bearing dominant characters, and one half being both domi- 
_ fant and recessive. : : 
The regularity in the variation as just described in the second 
_ and later generations is accounted for by supposing that = 
