When I've had a cat and a kitten, I get a collar with a bell to put on the kitten. This at least allows the adult cat to be aware that the little one is getting ready to pounce.

Other than that, I'd just make sure that you give Geourge a little quality time each day away from Milly.

Finally, did he really chase her, or just play a game of chase? My kitties chase each other all the time but I know they are just doing it for fun because they don't go at full speed or they are really noisy in the process.