Science Shows How Eye Sees Without Light

Three University scientists can now demonstrate in a test tube how the eye sees in dim light, a meeting of the Society of Biological Chemists will be told today.

Experiments on the phenomenon, long an enigma, have been going on here for over a year. George Wald, professor of Biology, Ruth H. Hubbard, research fellow in Biology, and Paul K. Brown, reported to the Society last year that they could manufacture synthetic rhodopsin, a red pigment found in the retina which helps translate light waves into the sensation of sight.

In the first paper on the subject, Miss Hubbard told how four substances were assembled to produce the synthetic rhodopsin.

When placed in the dark, the mixture undergoes certain changes as the various ingredients inter-act. A yellow pigment is formed first, then the red rhodopsin.

Dark adaptation, the process whereby the eye slowly becomes more sensitive to dim light, is due to this synthesis of the four substances in rhodopsin.

A second paper explains how the rhodopsin transfers the chemical reaction to the optic nerve which carries the impression to the brain. The response of the nerve is known to lead not only to sensations of sight, but also to electrical changes.

With the use of silver salts, the team of three biologists formed an electrical cell with their solution which produced current, the strength of which depended upon the reaction in the solution when light hit it.