We do not know, but observation has often shown the first two phenomena accompanied by that state, and that is enough for them to become signs in future';'' lastly, an operation which, beyond first appearances, scrutinizes the body and discovers at the autopsy a visible invisible: thus the examination of corpses has shown that in cases of pleuropneumonia with expectoration, the sudden interruption of pain and the gradual weakening of the pulse beat are signs of a hepatization of the lung.