60 THE MEANING OF EVOLUTION 
behavior of the animal world. It is difficult to prove 
that there is going on under our eyes a steady and 
real improvement in the adaptation of the animals and 
plants around us to the situation in which they are 
placed. As far back as man’s memory runs they 
seem to have been about what they now are; as far 
even as man’s historical record runs they seem to have 
suffered no great alteration. The Egyptian of the old 
tombs is much like the Egyptian of the same rank 
to-day. The African of the tombs has the African 
features of to-day. Under such circumstances it is 
hard to prove that there is a steady and undoubted 
advance. For the most part the balance of the ani- 
mal world is fairly even, and any species does not 
ordinarily change rapidly enough or migrate widely 
enough to show us its new features. It is difficult to 
see the struggle which we are so sure is going on. 
The life of animals is so hidden in many of its de- 
tails that their joys and sorrows, if such we may call 
them, scarcely fall under our observation. Now and 
then an opportunity comes to see the process of adap- 
tation work itself out. The struggle for existence be- 
gins anew and is carried on with special vigor, with 
victory, temporary or permanent, to one of the par- 
ticipants in the struggle. 
The opportunity to observe such a change is pre- 
sented in the United States by the introduction of the 
