"My old cat developed hypertension blindness across forty eight hours. After an evening of disorientation, he flatly accepted his condition and began to work on his new territory, setting off in random directions until he encountered something he knew. By the next day he had mapped his way to the food, the water, the litter box, the favourite chair. He had stopped bumping into things. He would approach a surface head on, then turn suddenly but smoothly (as if he had detected its temperature, or its smell, or some small air movement associated with it, a draught moving along the skirting board, say, down the steps from the hall, into the kitchen) and walk along it as quickly as he had before the lights went out."
