Abstract: In a dialysis system wherein blood is removed from a patient's vascular system and passed through a dialyzer system comprising an inlet arterial line, a dialyzer, and an outlet venous line, the blood being fed via the inlet arterial line to the dialyzer and returned to the patient via the outlet venous line, a material having a physical property differing from that of blood is injected at a point in the venous return line. The fluid in the dialysis system upstream from the injection point is monitored for the presence of the different physical property whereby direct recirculation from the venous return line to the arterial intake line is detected.

Abstract: A portable light-weight hanger for supporting a bow, rifle, or the like from a tree without damaging the tree. The hanger comprises a J-shaped elongated member having an upper rear portion and a lower front finger projecting forwardly therefrom. A relatively small hollow tube extends horizontally through the upper rear portion, and a flexible cord extends entirely through the hollow tube.