The possible functions of glutathione in the lens as well as in the rest of the body have been a matter of discussion since the discovery of this substance by Hopkins.1Although much experimental work has been done on the glutathione in the lens, its actual isolation from this organ was only recently accomplished by two of us.2That glutathione has an important function in the metabolism of the lens appears likely from the work of Adams,3who showed that the oxygen uptake of a lens extract became nil when glutathione was dialyzed out ; readdition of glutathione to the extract caused a resumption of its oxygen uptake. It was indicated that this substance is a constituent of an auto-oxidation system in which the sulfhydryl can act as a hydrogen donor, being oxidized to the disulfide form, which in turn can accept hydrogen from a "thermostable residue." It