THE DETERMINATION OF LUNG VOLUME WITHOUT FORCED BREATHING.

1. A method is described for the determination of lung volumes without forced breathing. 2. The method determined total capacity and its subdivisions coincidently. 3. The values obtained were independent of the length of time during which the subject rebreathed after gas mixture was once established. 4. The maximum error of the method is estimated at +/- 3 per cent of the lung volume determined. Considerably greater variation from the mean may be encountered, however, because of inconstancy in the lung positions assumed by the subject.