what do you mean "Grounding the bath"

hello, very one, i m new in MEA, i m reading a manual for MEA, here is a problem, what does the bath mean? maybe "medium"? so that means i have to place a wire into the medium when i m recording, am i right? but why should i do that? wating for your answer... thank you very much!

Dear Adamyuan,
the bath is indeed the medium around the cells. For any electrical recording, there have to be two electrodes, the recording and the ground/reference electrode. If you have an MEA with a large internal reference electrode already integrated, you don't need the Ag/AgCl wire electrode to ground the bath, otherwise you do.

Best regards Frank MCS

thank you! problem solved