Abstract: Apparatus for use in surgically removing tumorous neurological tissue comprises a handpiece in which a tool tip vibrating transversely to its long axis in the ultrasonic range, is mounted an irrigation fluid outlet for introducing fluid adjacent the tool tip to flush the operative site, and a fluid inlet adjacent the tool tip for withdrawing a fluid mixture from the site.

Abstract: A breath volume indicating system has a regulator controlling the flow of gas from a source of gas under pressure to a supply system delivering the gas under pressure to a patient as well as to a chamber providing a fixed volume to receive a supply of the gas. The regulator includes two valves respectively operatively associated with the supply system and the chamber, each valve being operable simultaneously between closed and open positions. In the closed position of the valves, generally coinciding with an inhalation period of the patient, the regulator provides a flow of the gas to the patient through the supply system and into the chamber, concurrently, and, in the open position, generally coinciding with the exhalation period of the patient venting of the supply system (and thereby the patient) and the chamber, concurrently.