This instrument has been used by us for induction of pneumothorax in 30 cases of pulmonary tuberculosis and for refills of air on more than 553 occasions. It is preferred to the standard types of apparatus for giving artificial pneumothorax, which employ columns of water in bottles to displace air into the chest, because it is smaller, the operation is simpler, the air is under much more delicate control, the intrapleural pressure may be read more conveniently during the introduction of air, and the U-tube of the manometer is filled and refilled with water more easily. The pump can be used for various other clinical purposes as well, since it is capable of driving efficiently either gases or fluids.
The mechanical details of the pump have been described elsewhere,1 and it is necessary here to point out only the chief characteristics. The pump consists of a wheel 14 cm.