An Apparatus for Fixation and Supravital Staining of Tissues by the Perfusion Method

An apparatus is described for the perfusion of the circulation which permits accurate control of the temperature, pressure and rate of flow of the perfusing fluids. Using this apparatus, the tissues can be perfused initially with saline and subsequently with a fixing solution or supravital stain without changing the cannula. The apparatus can be pre-set to any given requirement, and will thus give reproducible results. It is not suitable for the application of warm volatile fixatives, but these can be perfused cold after preliminary perfusion with warm saline. Perfusion is improved by the subcutaneous injection of heparin before death, and by the administration of amyl nitrite either in the perfusing fluid or as a vapor during anaesthesia.