What happens when you eat a battery?

We got into a heated discussion at lunch today about what would happens if a person eats a battery. Obviously, if the seal on the battery is broken then very bad things happen. But what are the chances that the battery seal will stay in-tact and the battery will simply pass through your system?

One argument that was proposed was that the battery casing was designed to keep the battery acid in, so is it also enough to keep stomach acid out?

Perhaps some of you engineers-turned-med-students would like to chime in?

© Josh Staiger, joshstaiger@gmail.com