Conceive a man, gifted with the keenest intellect, but not knowing from experience, that sucklings grow and become men, and imagine what he would say, if you were to tell him this:
“Know, that the little being you see here, is a suckling, that is, a developing human being, who by and by will become thicker and taller. The bones of his body will become firmer and longer. The muscles that animate these bones will likewise increase in size. The same will happen with regard to his eyes, ears, nose, mouth; to his head, body, and feet; every component part of his small body will be developed further and further, until the child will become a perfect man.”
There is no doubt, that he who does not know all this from experience, will shake his head at it.
But if you were to tell him: “This development and growth have their source in the baby’s sucking at the mother’s breast a white juice called milk, and out of this milk all the constituent parts of the child are manufactured within himself,”—certainly your hearer would laugh in your face, and perhaps call you a credulous fool.