He was a long, thin old gentleman in his middle seventies with a faraway unseeing look in his eye, not unlike that which a dead halibut on a fishmonger’s slab gives the pedestrian as he passes. It was a look which caused many of those who met him to feel like disembodied spirits, so manifest was it that they were making absolutely no impression on his retina.

• P. G. Wodehouse, Cocktail Time