Fulfillment by the lungs of their bellows function depends largely on their resiliency and elasticity. Unless the lungs can readily comply with the changes in the thoracic cage during inspiration and expiration, ventilation will be seriously impaired. Pulmonary compliance is expressed as the ratio of lung volume in liters to intraesophageal pressure in centimeters of water. The present study is...

Pressure measurement devices can be classified into two groups: those where pressure is the only source of power and those that require electrical excitation. The mechanical style devices that are only excited by pressure, such as bellows, diaphragms, bourdons, tubes or manometers, are usually suitable for purely mechanical systems. With these devices a change in pressure will initiate a mechan...

A spot that flickers at 16 Hz between two luminance levels (on a grey surround) has an appearance of metallic lustre, which we call 'monocular lustre'. Binocular and monocular lustre were measured in comparable conditions by a rating procedure, and both were reported only when the light and dark values of the flickering (or binocularly fused) spot straddled the surround luminance, so that the s...

A positive response from a metal detector when run over an area of the body is a strong positive indicator of the presence of a metallic object. If there is a possibility of a buried metallic foreign body this positive finding should not be ignored.