THE VALIDITY OF THE CENTRIFUGE METHOD FOR ESTIMATING AGGREGATE CELL VOLUME IN SUSPENSIONS OF THE EGG OF THE SEA-URCHIN, ARBACIA PUNCTULATA

Abstract

Observations of the aggregate volume of Arbacia eggs, when centri-fuged in capillary tubes, as a function of centrifugal force, and of duration of centrifuging, were made. Data on the comparisons of such total cell volume contained in suspensions of Arbacia eggs as evaluated by 3 methods (counting in hemacytometers, centrifuging at 2700 and 7700 X gravity, and direct counts of diluted suspensions) are given. It is submitted that the centrifuge method is reliable, to within approx. 10%, for estimation of the total volume of cells in a suspension of unfertilized eggs of A. punctulata in sea water provided it be used with the necessary force and duration for sufficient packing of the cells. Cells so centrifuged remained viable, since, upon removal from the capillary, they cleaved and underwent considerable embryological development.