100 DOMESTICATED ANIMALS AND PLANTS 
Some of the units are present in a high degree, and these are 
strongly developed, giving the visible appearance of the indi- 
vidual; others are present in low degree, remaining undeveloped, 
and out of evidence, leaving us to assume their absence. 
The proof that every individual really possesses all the normal 
characters of the race is the fact that he will transmit them to 
his young, and that is why the offspring of two bay horses may 
be something else than bay. When such an offspring is, say, 
black, we assume that one and possibly both of the parents 
possessed unit characters of black as well as bay ; that is to say, 
that some of the ancestors were black. Not only that, but if any 
of the ancestors were black, we assume that black unit characters 
are present, that they will be certainly transmitted, and will one 
day crop out. 
The sire will transmit milking quality as well as the cow, 
though it is a character that develops only in the female. The 
truth is that he, as well as the female, possesses the character, 
but it is not functional in his case. It loses nothing by this fact, 
however, in transmission. People are often puzzled to account 
for traits of character that outcrop in children, but were notice- 
able in neither parent. The truth is that all ancestry is more 
or less mixed, and every parent can be counted upon to trans- 
mit many more unit characters than are present in his visible 
make-up. This is reversion, the so-called mystery of transmis- 
sion or “ failure of heredity,” as it is often erroneously denomi- 
nated. It is no failure at all, for real unit characters are all 
transmitted ; whether they ever develop and become evident 
depends upon a variety of circumstances, chief of which are 
their relative intensity and the conditions of life to which the 
individual happens to be subjected during development. 
Characters developed and characters latent. As has just been 
implied, the visible personality of the individual depends upon 
those particular characters that happen to have developed, and 
not at all upon that other and extensive possession of unde- 
veloped or, as they are called, ‘latent’ characters. The term 
