The inhibition of luminescence by light—Dynamics of the reaction

Abstract

The luminescence of ctenophores is inhibited by light of a given intensity acting for a sufficient length of time. This is true for both the intact animals and for the luminescent substance obtained from them. The following experiments were made with a view to determining the dynamics of this photochemical reaction in the case of the luminescent granules of Eucharis multicornis.

A large specimen of Eucharis was shaken in a flask until all gross structures had disappeared, and the fluid remaining had the appearance of an opalescent emulsion. This was passed through a coarse filter, the resulting filtrate being a stable suspension of microscopic granules of photogenic material which, when subjected to the action of appropriate reagents, would glow with a blue-green light. In practice this was accomplished by pouring 50 cc. of the suspension into 200 cc. of tap water. The result was a bright light which lasted 5 to 7 seconds—an amount sufficient to produce deep blackening of an “extra rapid” photographic plate (Cappelli's).

In order to study the dynamics of the action of light on the luminescent granules, 300 cc. of the suspension were exposed in a broad dish to the action of a 200 cp. lamp at 50 cm. distance. At chosen intervals, 50 cc. of the suspension was removed, agitated, taken to the dark room, mixed with 200 cc. of tap water, and the photographic plate kept at a fixed distance. At chosen intervals, 50 cc. of the suspension was removed, agitated, taken to the dark room, mixed with 200 cc. of tap water, and the photographic plate kept at a fixed distance. After the exposure the plate was numbered, then 'carefully covered and kept until the end of the experimental series.