Nature will not, however, give in altogether to man’s foolish acts; for even when we cross the species we get a thing that cannot reproduce. The strict laws here step in and say: “So far shalt thou go, but no farther.” The mule is an example of what I mean. The mule is the result of breeding the ass to a mare. It is hybrid; it cannot reproduce its kind. So in order to have mules we must always use an ass and mare. The mule cannot reproduce its kind because it is a born eunuch. That is, it has no seed to give life to eggs. Now in some respects the mule is more useful to man than the horse. Again we see that the laws controlling our lives are often adjusted to our desires when these desires are for our benefit. So we can breed from a mare and stallion ass; but cannot go any farther with the species. It is about the same with the inbreeding of zebras and horses, although this has not yet been carried far enough to determine what the outcome will be. But don’t forget this fact: ass and horse, zebra and horse are all the same species――equines. You have seen how birds and hens lay their eggs in a nest, and how, if they have received the male germ, the eggs bring forth their young. In the higher forms of animals――those who nurse their young――exactly the same PROCESS takes place but under different details. In these higher animals, the dog, for instance, we have the ovaries making the eggs just as in the birds. At certain intervals in the year these eggs slip from the ovaries into a nest lying just down beneath the two ovaries――one on each side of the female dog. This nest we call the uterus――or, in ordinary terms, the womb. When these eggs slide into their nest they produce an inflammation of the parts; also a peculiar odor. This is another wonderful law of nature, for without these conditions life would soon cease to exist. The inflammation gives the female dog――bitch is the proper name――a longing to be a mother. It is nothing impure in her, nothing to be ashamed of, but a condition to be proud of and to cause reverence in those of pure minds. The odor is to tell the male that now he must do his share in keeping dogs on the earth. So they mate. When each little egg is vitalized by the dog’s sperm, they remain in the womb――the bitch’s nest――for nine weeks, growing day by day until they are ready to come into the world. Then did you ever see such a beautiful sight as the watchful and happy mother? Never, if you have all the real feelings of the genuine boy. There must arise that in you which we all feel but cannot explain. Kind words come to you as you watch the happy dog mother; gentle strokes as she cuddles to warm her little babies. And yet there are boys who have so little understood the beauty and wonder of all this act of reproduction that they sniggle and make sport of the desires of the innocent want-to-be-mother dog.