REVERSION TO THE WILD FORM. 209 
unequal (compare p. 17). All such relapses are to be 
brought under the law of interrupted or latent transmission, 
although the number of intervening generations may be 
enormous. 
When cultivated plants or domestic animals become wild, 
when they are withdrawn from the conditions of cultivated 
life, they experience- changes which appear not only as 
adaptations to their new mode of life, but partially also as 
relapses into the ancient original form out of which the eul- 
tivated forms have been developed. Thus the different 
kinds of cabbage, which are exceedingly different in form, 
may be led back to the original form, by allowing them to 
grow wild. In like manner, dogs, horses, heifers, etc., when 
growing wild, often revert more or less to a long extinct 
generation. An immensely long succession of generations 
may pass away before this power of latent transmission be- 
comes extinguished, 
A third law of conservative transmission may be called 
the law of sexual transmission, according to which each sex 
transmits to the descendants of the same sex peculiarities 
which are not inherited by the descendants of the other sex. 
The so-called secondary sexual characters, which in many 
respects are of extraordinary interest, everywhere furnish 
numerous examples of this law. Subordinate or secondary 
Sexual characters are those peculiarities of one of the two 
sexes which are not directly connected with the sexual 
organs themselves; such characters, which exclusively belong 
to the male sex, are, for example, the antlers of the stag, the 
mane of the lion, and the spur of the cock. The human 
beard, an ornament commonly denied to the female sex, be- 
longs to the same class. Similar characteristics by which 
VOL. I. P 
