Another of the earliest strips in which Snoopy gets thought balloons. He becomes much more of a real character with them, instead of just a creature that does funny things and has funny things happen to him.
Snoopy refers to chasing the ball as a way of making a living. Is kind of a throwaway line, but it does imply that Charlie Brown must be feeding him, putting another point in the owner column.
I'm not sure why I'm fascinated by the symmetrical gasping and panting in panel six. Seems a bit overdone, though.
