We sought a technique to preserve lung tissue for micrography with air-space dimensions unchanged from the fresh state. In our hands, conventional techniques were problematical. Aware of the possibility that distortion might be caused by inadequate mechanical fixation of elastin, we dehydrated the still-inflated lung by intravascular perfusion with graded ethanols. Canine and rabbit lungs so prepared had straighter alveolar septa, greater air-space dimensions, and an improved correlation with light-scattering measurements. Bovine ligamentum nuchae (mostly elastin) was only partially fixed by glutaraldehyde or osmium tetroxide but was effectively stiffened by dehydration. We conclude that perfusion dehydration aids in the faithful preservation of parenchymal configuration, probably by mechanical fixation of elastin.