The Effect of Fluorides on the Echinoderm Egg.

Abstract

In the course of some experiments by one of us on the action of fluorides on coagulation of the blood it occurred to us to note the effect of fluorides on other cell structures. The arbacia egg, since it is reliable and convenient to work with, was chosen for study.

The eggs were placed in 70 cc. of sea water containing one cc., of an isotonic solution of NaF, KF, K oxalate, and K citrate respectively. An immediate flocculation of the eggs occurred in the sea water to which NaF, or KF were added. No similar phenomenon occurred with K oxalate or K citrate, or when artificial sea water was used in which Ca was absent. The flocculation, therefore, seems to be a direct effect of the fluorine ion and is not due to the removal of the calcium from the sea water. The flocculation was characterized macroscopically by the instantaneous clumping of the cells into large masses. Microscopically the groups of cells seemed to be enmeshed in a bed of gelatinous material. No such gelatinous material was noted except in the cases where NaF or KF were added. This phenomenon occurred both in the unfertilized and the fertilized eggs.

No change in the size of the cells was noted for a period of over two hours. The H-ion concentration of the solutions was followed potentiometrically and showed practically no deviation from the normal in all solutions.

Further observations were made on the time and rate of division in the fertilized cell. Isotonic solutions of KF, NaF, K oxalate, and K citrate were added within five minutes after fertilization and the time of the first division and the number of cells going through the first division each minute after this, was noted.