For all this seemingly impractical sniffing about, Leeuwenhoek was a hard-headed man. He hardly ever spun theories, he was a fiend for measuring things. Only how could you make a measuring stick for anything so small as these little beasts? He wrinkled his low forehead: “How large really is this last and smallest of the little beasts?” He poked about in the cobwebbed corners of his memory among the thousand other things he had studied with you can’t imagine what thoroughness; he made calculations: “This last kind of animal is a thousand times smaller than the eye of a large louse!” That was an accurate man. For we know now that the eye of one full-grown louse is no larger nor smaller than the eyes of ten thousand of his brother and sister lice. But where did these outlandish little inhabitants of the rainwater come from? Had they come down from the sky? Had they crawled invisibly over the side of the pot from the ground? Or had they been created out of nothing by a God full of whims? Leeuwenhoek believed in God as piously as any Seventeenth Century Dutchman. He always referred to God as the Maker of the Great All. He not only believed in God but he admired him intensely--what a Being to know how to fashion bees’ wings so prettily! But then Leeuwenhoek was a materialist too. His good sense told him that life comes from life. His simple belief told him that God had invented all living things in six days, and, having set the machinery going, sat back to reward good observers and punish guessers and bluffers. He stopped speculating about improbable gentle rains of little animals from heaven. Certainly God couldn’t brew those animals in the rain water pot out of nothing! But wait.... Maybe? Well, there was only one way to find out where they came from. “I will experiment!” he muttered. He washed out a wine glass very clean, he dried it, he held it under the spout of his eaves-trough, he took a wee drop in one of his hair-fine tubes. Under his lens it went.... Yes! They were there, a few of those beasts, swimming about.... “They are present even in very fresh rain water!” But then, that really proved nothing, they might live in the eaves-trough and be washed down by the water.... Then he took a big porcelain dish, “glazed blue within,” he washed it clean, out into the rain he went with it and put it on top of a big box so that the falling raindrops would splash no mud into the dish. The first water he threw out to clean it still more thoroughly. Then intently he collected the next bit in one of his slender pipes, into his study he went with it.... “I have proved it! This water has not a single little creature in it! They do not come down from the sky!”