274 THE OVARIAN EGG. 
its support in other ways. Another most inter- 
esting chapter connected with the maintenance of 
animals is found in the various methods and dif- 
ferent degrees of care with which they provide for 
their progeny : some having fulfilled their whole 
duty toward their offspring when they have given 
them birth, while others seek hiding-places for 
the eggs they have laid, and watch with a certain 
care over their development, and still others feed 
their young till they can provide for themselves, 
or build nests, or burrow holes in the ground, or 
construct earth mounds for their shelter, and by 
a variety of means secure them from possible 
dangers. 
But, whatever be the difference in the outward 
appearance or the habits of animals, one thing is 
common to them all without exception: at some 
period of their lives they produce eggs, which, 
being fertilized, give rise to beings of the same 
kind as the parent. This mode of generation is 
universal, and is based upon that harmonious 
antagonism between the sexes, that contrast be- 
tween the male and the female element, that at 
once divides and unites the whole Animal King- 
dom. And although this exchange of influence 
is not kept up by an equality of numeric relations, 
—since not only are the sexes very unequally 
divided in some kinds of animals, but the male 
and female elements are even combined in cer- 
