o live the natural sort of life that was best for
him, the life of continuous struggle. He is, in short, a degenerate wild
duck; his wings are not so broad or so strong, the muscles of his breast
have grown puny and shrunken; he does not even want to fly far north in
spring or far south in winter. He is content with his farm-yard and
puddle. He has stopped _trying_, and so has stopped _growing_ too.

One more instance I will give you, boys, of the important place this law
of struggle plays in the lives of the very beasts. I was visiting some
time ago the museum in one of our universities. One of the professors
was with me, and we came to a case full of plaster casts of brains, the
brains of animals. While looking at these you could, of course, easily
compare their size and character, and form some opinion of the
intelligence of the animal itself. The professor pointed out to me one
very interesting brain cast. It was taken from the head of a rhinoceros
that had lived very long ago--lived at the same time as mammoths and
other antiquated animals. It was quite a large and well-developed brain.
We next went to another case and took out the cast of a common
rhinoceros, such a one as lived in our own times, and it was very
evident that the present-day rhino was not nearly so large or
intelligent as his progenitor of long ago. This seemed at first very
strange; for why should the rhino's brain have degenerated while they
are still struggling forward in the march of life? The answer is to be
found in the sort of battle they have to fight. When the antediluvian
rhino lived, the world was peopled with terrible monsters, brutes of
great strength and savagery. With these he had no easy time of it. He
had to match himself against them. Great strength alone was not enough;
he needed cunning as well. Struggle he must, and struggle hard or go
under; and he survived because he did struggle hard and did not go
under. When, however, most of the monstrous forms of life had gradually
passed away, the rhinoceros had no enemy he stood much in dread of. The
milder animals of a later day get out of his way. There is nothing to be
gained by contending with him. He needs no longer to strive; life comes
easily, and food is plenty. Thus it is that a perpetually "good time"
resulted in weakening his head and lowering his intelligence. He is,
indeed, the degenerate descendant of a noble parent.

So, boys, wherever we look, the same result is taught