“…This is equivalent to lengthening the inflation part of the cycle and by inference from the work of Motley et al (1948), Coumand et al (1947, as reviewed by Watrous et al (1950), the cardiac output will fall. The better known examples of respiration pumps are, Pinson's Pulmonary Pump (Pinson and Bryce, 1944), Blease's (1946) Pulmoflator (Mushin andRendell Baker, 1953), M0rch's (1948) Automatic Machine, James's (1950) Respirator, the Beaver (1953 Respirator, the Radcliffe Respiration Pumps (Russell and Schuster, 1953) and Engstrom Universal Respirator (Engstrom, 1954). Some of these have means whereby the stroke volume can be adjusted readily to overcome the objection mentioned above.…”