Abstract
1. The ions of Ca and K condition general luminescence, and are therefore necessary to the conduction of the impulse. 2. In van't Hoff's solution from which Mg is omitted, Beroe shows hyperirritability with respect to luminescence. This is the result of the action of Ca and K ions unantagonized by Mg. 3. The luminescent material spread on filter paper does not show luminescence in sea water, NaCl, MgCl(2), or saccharose solutions isotonic with sea water. In solutions of CaCl(2), SrCl(2), BaCl(2), KCl, and K(2)SO(4) the indicator paper glows with a bright luminescence. 4. In dark adapted Beroe, luminescence is inhibited by a certain quantity of light. This quantity has an average value of 57,285 meter-candle-minutes, which is twelve times the value given by Mnemiopsis.