Quotation by Friedrich Nietzsche

Man is at his furthest remove from the animal as a child, his intellect most human. With his fifteenth year and puberty he comes a step closer to the animal; with the sense of possessions of his thirties (the median line between laziness and greediness), still another step. In his sixtieth year of life he frequently loses his modesty as well, then the septuagenarian steps up to us as a completely unmasked beast: one need only look at the eyes and the teeth.