Abstract: A medical instrumentation electrode apparatus for use in connecting wiring from an external medical instrument, such as an electrocardiograph machine, with an area of a patient's skin. The apparatus includes a vacuum bell which is interconnectible with a resilient bulb for partially evacuating same and causing a pliable ring disposed on the open end of the bell to collapse against a patient's skin. In this manner, a disposable contact held in place within the vacuum bell by a core portion of the bell is held in electrical contact with the skin area. The core portion is integrally formed with the vacuum bell and includes an upper protruding end for connection with the resilient bulb, and is further provided with an air communication passage extending between the bulb and the interior of the vacuum bell.