"It is very wonderful, mamma," Elsie said, awed by the mystery, even though she was very far from grasping the whole of it. "And the birds, mamma, have they stamens, and eggs inside? I thought their eggs were outside, in a little nest. And some of them are, mumsey, because, you know, I have seen them lots of times."
"Yes, the eggs come out where you can see them, in time, as the frog's do, but at first they are inside the mother bird, as they are with the frogs and all animals. Only, it is not with the birds as it is with the frogs, for the bird's eggs must be fertilized by the male zoösperms while they are still within the mother bird. The zoösperms must enter the ovary as the pollen must enter the ovary of the plant. So the male bird, like most male animals, has a stamen which is a repetition of that of the flower, made of such a shape that it can reach the eggs in the mother bird's ovary and fertilize them there. Then they come out, they are 'laid' as we say, and we see them in the nest which the mother and father birds have prepared for them. And just as the seeds need to be covered and kept warm, when they have fallen from the ripe pods to the ground, in order that they may live and grow into baby plants, so the bird's eggs must be covered and kept warm and safe in order that they may grow into birdies. It is just here that you may see where the honey of the plants begins to become love in the higher species. For instead of leaving the eggs to be protected or not, according to chance, as is the way of the plants, the mother bird covers and warms and protects them herself. She sits on the nest and keeps them safe with her own body and feathers. Isn't that lovely! And the father bird goes to market in the woods and fields and brings her the daintiest and best food he can find."
"Isn't he _nice!_" said Elsie appreciatively.
"Yes, he is nice, and so is his wife, the mother bird. Just think! A bird is the most energetic and tireless creature in all animated nature. It is always on the move, urged by the force and overflowing life within its body, and to sit there quietly all alone on the eggs day after day and night after night--oh, it must be hard, so hard that we can scarcely realize the extent of the sacrifice she is making for her little children. That is what love is like. And the higher a creature is in the scale of life the more love it has, until, in men and women, the acme is reached and they not only give up their comfort for each other, and especially for their children, but even their lives themselves. With human beings one can tell how high a given one is in the scale of humanity by the amount of love he has. Some persons have very little, and they are nearer the animal plane: some have a great deal, and the more they have, the less selfish they are, the higher they have risen. For love is the real stamen that fertilizes the world and makes it grow, and the more one has of it the more life one gives to the universe."