Force Exerted by a Single Cilium of Mytilus Edulis

Abstract

1. Angular velocities of the large abfrontal cilium of Mytilus beating in media of various viscosities were measured. 2. An equation for the force produced by a single cilium in free motion was derived by hydrodynamical methods. Expressing the force in terms of torque referred to the base of the cilium: Torque = angular velocity x viscosity x (length of the cilium)3 x constant. The constant appropriate to the effective stroke of the large abfrontal cilium was found by a model experiment to have a value of 1.1 . 3. The torque exerted by the cilium in normal sea water was 2 x 10-8 dyne.cm. Increase of viscosity resulted in increase in the torque. 4. The maximum power developed by the cilium was calculated to be 1.2 x 10-6 erg/sec. Assuming that a single cilium is made up of 20 subunits, the power developed by a single subunit is 6 x 10-8 erg/sec., which is of the same order of magnitude as the power developed by a single spermatozoon of a sea urchin (Carlson, 1959).