UNIT CHARACTERS IOI 
is not a good one. They are latent only in the sense that they 
are not evident except as they outcrop in succeeding generations, 
when, with other blood lines, the new combinations become 
sufficiently strong or otherwise favorable to bring them out. 
They are not latent in the sense that their presence cannot be 
suspected. If we examine carefully all the unit characters in 
any race, we shall know positively what characters will be pos- 
sessed by the descendants, but as to which will develop and give 
visible evidence of their presence in any particular individual 
we cannot predict. We shall see later, however, that if both 
sire and dam are black, knowing nothing about other ancestry, 
the offspring will stand even chances of being black also. If all 
the grandparents, however, were red, the offspring, even of 
black parents, would stand one chance in four of being red; or, 
what is the same thing, one fourth of all such offspring would 
be red and one half black, with the other one fourth unknown. 
Characters dominant and characters recessive. Some charac- 
ters are dominant, that is, strong and easily seen, while others 
are difficult of detection or easily covered up and obscured by 
stronger ones. Thus, in flowers, pink is easily lost in red ; light 
blue, in purple; or yellow, in green. Small size is obscured by 
large size, and, in general, certain characters are much more 
readily seen than others. Those that are most evident are called 
the dominant, as distinct from the recessive, which are the less 
evident. Quite aside from mere visibility, too, certain characters 
seem more likely to appear in crossed forms than do their cor- 
responding but equally noticeable characters (see the discus- 
sion under Mendel’s law and the illustrations of guinea pigs 
in Chapter XI). 
Correlation of characters.! The relations between the many 
unit characters that make up any race are in many respects 
striking. Certain characters move together in the relation of 
cause and effect. Such characters are said to be highly corre- 
lated. Certain others seem naturally opposed, and here the 
1 Principles of Breeding,” chap. xiii. 
