New facts on neutralization of retinal induction.

Abstract

Physiological effects remaining within a retinal area and around it after exposure to colored light are designated direct induction and indirect induction respectively. 1. The indirect induction was shown to disappear when the same area was illuminated subsequently with colored light complementary to the pre-illuminating light. 2. The indirect induction was reduced or extinguished also when the direct induction was modified by an illumination with strong white light restricted to the pre-illuminated area. 3. The indirect induction pre-established by the first patch was extinguished when the direct induction was neutralized with the spreading induction from the second patch of the same color presented at a distance subsequently. 4. This fact cannot be accounted for in terms of the neutralization described by Motokawa, because Motokawa's effect could be observed only between two patches complementary to each other. Therefore, it was proposed to distinguish the present phenomenon from Motokawa's and to designate it “secondary neutralization.” It was meant by this term that the effect occurs secondarily following the neutralization of direct induction. 5. Some experiments supporting this interpretation were presented.