The ancient procedure of cataract couching has, in more recent times, been superseded by removal of the lens. Most recently prosthetic lenses have been implanted into the aphakic eye, and there has been talk of transplantation of the lens and even of regrowth of the lens in man. Theoretically the best replacement of the lens, short of its regrowth, would be evacuation of the lens contents and replacement by a suitably transparent substance. The purpose of the present paper is to report such an attempt. The lens substance is evacuated through a small opening in the capsule and replaced with transparent material. The new lens is thus held in its normal position and retains its normal connections. With an elastic or viscid filler it might even be possible to preserve accommodation. Beef lenses have been evacuated and refilled in vitro by the following means. The lens capsule is punctured by