I read a newspaper article some years ago which told about a horse who had shied when he came to a stump on the road. Subsequently, every time the horse came to that same stump, he shied. The farmer dug the stump out, burned it, and leveled the old road. Yet, for twenty-five years, every time the horse passed the place where the former stump was, he shied. The horse was shying at the memory of a stump.