Rande's comments about the black slime or sludge that collects in tubes.
This is the infamous biofilm that plagues more than just waterbaths.  There
is a huge amount of research done on Biofilm to eliminate the stuff, in
disease processes (hip prothesis, cystic fibrosis, and shunts, etc),
contact lenses, gas tanks, teeth (plaque formation!)   Big corporations
spend millions on R and D of this slimy subject.

Have done frozen sections via a special technic on biofilms, slices of slime!
The term biofilm has now been transferred to any collection of sludge on
the porcelain throne in my house, I no longer scrub the loo, I remove
biofilm! and I know people on my campus who have volunteered their toilets
to study that particular biofilm formation, ah the joys of in the field
research and get paid for it.

Sorry, my sense of humor got the best of me to pass on some strange pearls
of wisdome,  must be the eclipse of the moon arriving tommorrow night that
is causing it.

Gayle Callis
Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303