> A while back I heard about a short story about an atom which spent a
> while as part of a CO2 molecule, then as part of a person, then in a
> glacier, etc.  Sounds like something Azimov would write.  Anybody
> heard of something like this?  If so, I'd like to track it down for a
> conservation of mass lecture for a bunch of non-scientists (and I get
> to assign some background reading).  Thanks in advance.

> Tom Crute