So they would fight their way down into the wet ground among the alders and willows, till they came to where their enemies were so thick and tall, that the acorns as they fell could not sprout in the darkness.

And so you would have at last, along the hill-side, a forest of beech and oak, lower down a forest of oak and alder, and along the stream-side alders and willows only.

And that would be a very fair example of the great law of the struggle for existence, which causes the competition of species.
What is that?
Madam How is very stern, though she is always perfectly just; and therefore she makes every living thing fight for its life, and earn its bread, from its birth till its death; and rewards it exactly according to its deserts, and neither more nor less.
And the competition of species means, that each thing, and kind of things, has to compete against the things round it; and to see which is the stronger; and the stronger live, and breed, and spread, and the weaker die out.
But that is very hard.
I know it, my child, I know it.

But so it is.

And Madam How, no doubt, would be often very clumsy and very cruel, without meaning it, because she never sees beyond her own nose, or thinks at all about the consequences of what she is doing.