In article <Pine.GSO.3.96L.980925085312.13407A-100000 at unixs5.cis.pitt.edu>, yaich+ at PITT.EDU (Lauren E Yaich) wrote: Lauren, I always use the cheapest grade of CO(2) available, without any detrimental effects on the flies. Go ahead, the flies won't mind the grade of CO(2) -- Greg Gloor Dep't of Biochemistry UWO