The volume of air at a transpulmonary pressure (PL) In infants and children, the ratio of VL minus lung weight to V25 averaged 1 -08 with a range of 0 58 to 1 84. The larger the lungs, the smaller the ratio, suggesting that fixation played a role in producing the small VL. In the emphysematous lungs, a significant correlation between the degree of emphysema and V25 was found. However, a statistically significant increase in V25 only occurred when the emphysema grade was greater than 5.Many studies have demonstrated a relationship between total lung capacity (TLC) and height, age and height, or height and weight in normal subjects.'-6 Since TLC is governed by the interaction of lung elastic properties, chest wall mechanics, and inspiratory muscle strength, it is of interest to document maximum lung volumes in excised lungs in which only lung elastic properties are a factor.In patients with emphysema, TLC has been shown to be increased in some studies,7-9 but not in others,'0-'4 and there is uncertainty as to what degree of emphysema is necessary to produce such a change.In morphometric studies of lung structure, it is common practice to inflate the lungs with a liquid fixative at a constant transpulmonary pressure (PL) of 25 cmH2O (2)(3)(4)(5)