The ability to transmit signals in the retina in the absence of impulses was tested by means of two agents (tetrodotoxin and procain) blocking the impulse transmission of stimuli. The slow potential (SP) and impulse discharge were recorded simultaneously from the optic nerve of the frog. Tetrodotoxin (0.5 µg/cm3) and procain (0.5–1%) introduced into the eye cup completely blocked impulses but had little effect on SP. Therefore, signals from the photoreceptors to the ganglionic cells can be transmitted in the absence of impulses. These data confirm also a conclusion drawn earlier that the SP originates as a result of electrotonic spread of the postsynaptic potentials (PSP) of ganglionic cells along the optic nerve. The agents blocking the impulse transmission of stimuli broke down the lateral inhibition between the "slow bipolars." Consequently, lateral inhibition spreads by means of the impulse mechanism in the transmission of signals. It is supposed that the interneurons participating in this spread are amacrine cells which possess the ability to generate impulses.