Based on the sample of the toxin you provided for us, we think you will need the following: an arcane quickener, four ectoplasmic resonators, and four pieces of runecloth.  With the vitreous focuser in tow, acquire the resonators from wraith and ghostly undead here in the Plaguelands!$B$BOnce you have these items, you should be able to load the counter agent into that cauldron.