“Boys and girls are only little men and women. And WE are much harder and hardier than they are--" (Peter liked the "we." Perhaps the Doctor had known he would.)--"and much stronger, and things that hurt THEM don't hurt US. You know you mustn't hit a girl--""I should think not, indeed," muttered Peter, indignantly."Not even if she's your own sister. That's because girls are so much softer and weaker than we are; they have to be, you know," he added, "because if they weren't, it wouldn't be nice for the babies. And that's why all the animals are so good to the mother animals. They never fight them, you know.""I know," said Peter, interested; "two buck rabbits will fight all day if you let them, but they won't hurt a doe.""No; and quite wild beasts--lions and elephants--they're immensely gentle with the female beasts. And we've got to be, too.""I see," said Peter."And their hearts are soft, too," the Doctor went on, "and things that we shouldn't think anything of hurt them dreadfully. So that a man has to be very careful, not only of his fists, but of his words. They're awfully brave, you know," he went on. "Think of Bobbie waiting alone in the tunnel with that poor chap. It's an odd thing- -the softer and more easily hurt a woman is the better she can screw herself up to do what HAS to be done. I've seen some brave women-- your Mother's one," he ended abruptly."Yes," said Peter."Well, that's all. Excuse my mentioning it. But nobody knows everything without being told. And you see what I mean, don't you?”