In previous communications on the pathology of pulmonary emphysema, it was suggested that lungs should be fixed under a continuous pressure of 25 to 30 cm of aqueous formalin for 72 hours to prevent shrinkage and distortion (pressure fixation). In the present communication, details are given of an improved apparatus for this purpose, together with further reasons for the procedure and further evidence to suggest that the volumes are comparable approximately to full inspiration in life. If followed by barium sulfate impregnation of lung slices, pressure fixation enables the pathologist to detect emphysema of all varieties. Technical assistance is not essential.