On safari on the human skin, fellow-travellers are not just the bacteria, as numerous on your body as people on earth, but the worm-like demodex among your eye-lashes; the dust mite, living off the skin you shed; and the head louse which creeps in a million British scalps.
Our lives depend on this strange ecology; fortunately for us, all the perfumes and detergents of Arabia will not wash it away.
