Two officer detailed to watch the mess kit washing line.  A medic is put on to guard the lister bag to see that all water that goes into it is chlorinated.  This is done by chlorine in a small glass vial which is broken and then the contents are dumped into the white lister bag, and it takes one-half hour before the water is thought to be purified.  The Halazone tablets do the same thing for water in the men’s canteens.  Before we had the Halazone tablets, men would carry the glass vials, and dump a little into the canteen.