Cyclic hemopoiesis and feedback control.

Hemopoiesis exhibits a variety of oscillatory phenomena. Since hemopoiesis is controlled by many feedback loops and since feedback loops are potentially oscillatory, it is possible that the observed oscillatory phenomena are the result of movement of hemopoiesis into an area of operation which favors stable oscillation. Although this hypothesis explains many of the observed phenomena and has had some predictive value, its important predictions have not yet been satisfactorily tested.