MECHANICAL PROPERTIES OF PROTOPLASM OF SEA URCHIN EGG .I. UNFERTILIZED EGG

1. 1. A magnetic particle method is described for the study of the consistency of the protoplasm of the sea urchin egg. The principle of the method is to get a spherical iron particle into the egg and then to move this particle in the protoplasm by means of external magnetic fields. It is possible to determine mechanical properties of the protoplasm from the response of the particle to the application of the force. 2. 2. The protoplasm of the sea urchin egg is visco-elastic. The properties of the protoplasm are approximately represented by a visco-elastic model consisting of a Voigt element and a viscous element connected in series. Approximate values of visco-elasticity constants are presented. 3. 3. The bearing of the present results on the structure of the protoplasm is discussed. © 1969.