[Significance of the pleura in respiratory mechanics]

The spirogram and transpulmonary pressure curve have been registered, the work of breathing and its subdivisions, pulmonary compliance have been measured in 14 rabbits under intravenous thiopental anesthesia (1st stage). 60 minutes after death the dead bodies have been placed in the box with the pressure, imitating the breathing movements (2nd stage). The isolated lungs have been placed into the Donders beel (3rd stage). The specific work of breathing and active nonelastic part of total work of breathing have been increased during the 2nd stage. The work of breathing and all its subdivisions were significantly increased in the 3rd stage of experiment. Pulmonary compliance was invariable. The whole pleural cavity provided decrease of mechanical work of breathing.