Abstract
Activated Hageman factor, when injected into the rabbit ear chamber, produces a delayed and prolonged inflammatory response characterized by prominent sticking and emigration of leucocytes. In contrast, preformed bradykinin evokes an immediate and more transient response in which leucocytic emigration occurs less frequently. It is concluded that either Hageman factor produces its inflammatory effects by mechanisms other than kinin release, or bradykinin released endogenously has effects quite different from those resulting from a single injection of the exogenous material.