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Show Keeping Up UmSciene ybcJenM er vice Science Service. WNU Service. Chemical of Sight Made to Rebuild Itself in Tube Visual Purple Now Is Regenerated VISUAL purple, a chemical compound in the eye, and necessary for seeing, has been made to rebuild itself in a test tube under controlled experimental experi-mental conditions, in the laboratory lab-oratory of Prof. Selig Hecht of Columbia university. , This is the first time that the process pro-cess has taken place under fully controlled conditions, which make its repetition possible. It is the first time since 1878 that visual purple has been regenerated at all, although al-though many physiologists have tried wihout success to repeat the experiment of Dr. W. Kuhne of Heidelberg university, who in that year reported having accomplished this very exciting biochemical feat Professor Hecht's associates in his present research are Drs. Aurin M. Chase, Simon Shlaer and Charles Haig. Found in the Retina. Visual purple is a pinkish-purple pigment or dyestufl of involved chemical composition, found in the rod-cells of the retina, or light-sensitive layer of the eye. Both in the living eye, and when chemically extracted ex-tracted into a glass vessel, it loses its color when illuminated, first turning yellow and then completely com-pletely colorless. In the glass vessel, it has never been turned back to its original color col-or again, except in the 1878 experiment ex-periment of Dr. Kuhne. But in the living eye the reaction is reversible, that is, if the light is shut oft the visual purple forms itself anew from the colorless product of its photochemical photo-chemical breakdown. Physiologists regard the success of Professor Hecht and his associates as-sociates in reversing the bleaching of visual purple at will as a very substantial forward step toward the ultimate understanding of the process pro-cess of seeing, because it is now possible to perform controlled experiments ex-periments in one very vital part of that process, where experiments have been impossible until now. Visual purple for the present research re-search was obtained from the eyes of frogs. The animals were kept in the dark for several hours; then they were killed quickly, and the pigment removed from their eyes by chemical extraction processes. |