This morning, our oldest son was trying to convince Moses, our 10 year old cat, to play with a piece of string. Poor Moses had just curled up on the end of my bed for a nap and was totally uninterested in a way you could only expect a cat to be. I explained to him that, just as kids like to play but adults really don't play that much, kittens are playful but older cats can't really be bothered. Moses is older than even Pop Pop, I told him, and prepared to explain how some people count cat years and dog years, and even considered a lesson on 'ratio'. But Moses was watching us through one open eye and had a sudden urge to itch behind his ear. Chas didn't even miss a beat, 'yeah, but Pop Pop doesn't itch like that.'