Galvanic currents are a direct electrical current. They need a closed circuit in order to function properly, which is why an individual must touch the volunteer when doing a half face application on him/her. If the circuit is not closed (the volunteer is not being touched during the application), the current will not be able to flow through them. Think of it like a string of lights on a Christmas tree, where if one light goes out the entire string is unable to work. Please note that we highly recommend that each individual performs their own galvanic application.