ELECTRIC IMPEDANCE OF ASTERIAS EGGS Apparatus

Several years ago the absolute value of the al ternat ing current impedance of suspensions of Arbacia eggs was measured at frequencies from 1 to 15,000 kc. (Cole, 1928b). I t was concluded tha t the egg membrane capaci ty was not as near ly a static capaci ty as the capaci ty of the red blood cell membrane (Fricke, 1925 a, 1933), bu t was of the polarization impedance type, similar to tha t which could be att r ibuted to the cell membranes of tissues (Cole, 1932, 1933; Bozler and Cole, 1935). Recent measurements (Cole, 1935) of bo th the resistance and reactance components of suspensions of Hipponog eggs at frequencies f rom 1.1 to 2,300 kc. showed the membranes to have static capacities and suggested complicating phenomena at the upper end of the frequency range. I t was then obvious tha t more complete measurements should be made not only on Arbacia eggs, bu t also on the eggs of other echinoderms.