An artist had all his paintings in a gallery. One day he popped in to see how things were going.

Artist: How are my paintings selling?

Gallery owner: Well, there is some good news and some bad news. A man came in the other day and asked me if you were a painter whose work would become more valuable after your death. When I told him I thought you were, he bought everything you had in the gallery.

Artist: Wow! That's terrific! What's the bad news?

Gallery owner: He was your doctor...