LuciferYellow:Afluorescentdyethatwasintroducedin1978.Itisbasedonthechemicalluciferindiscoveredin1888thatispresentinluminescentorganismssuchasfireflies.Ithasproventobeafiendishlyusefulproductwithmanyapplications.Inthisexperiment,itisusedinadissolvedformandinjectedintoaneuron,butithasalsobeenusedwithgoodeffectforimmunohistochemistry.LuciferYellowfluoresceswithbrightyellow-greencolorwhenstimulatedwithultraviolet(wavelength280nm)orblue(wavelength430nm)light.Becauseofthis,toviewthefluorescence,youneedanexpensivehalogenormercuryhigh-pressurelampandappropriatefilterstoblockoutUV,whichcandamageyoureye.Thisset-upwillcost$3,000ormore,inadditiontothecostofthemicroscope.