ABSTRACT
The methods appropriate to structural analysis of lung tissue depend on a number of factors, but perhaps the most critical, for several reasons, is the species to be studied. Species' size determines the feasibility of certain procedures. To determine their weight, the lungs must be excised from the chest. If this is done before fixation, as is often the case for autopsies, the lungs are weighed in the collapsed state after the heart is removed. Airway instillation of fixative at a head or pressure sufficient to inflate the lung is a simple way to achieve good preservation. Vascular perfusion of fixative while lung inflation is maintained at a given transpulmonary pressure requires that one choose the perfusion and inflation pressures. Determining peripheral air-space number is only possible late in fetal development when saccules appear. It depends on the lung being fixed at or close to full inflation. Autoradiography has been used to evaluate cell kinetics in the developing lung.
