It would seem that the lens is the ideal organ for transplantation because it is avascular and its antigen is contained in a membrane which probably does not allow protein molecules to pass. As long as the capsule is not damaged by the procedure, sensitization of the host is unlikely and consequently clear homo- and heterografts are to be expected unless the capsule itself sensitizes the host. That the normal lens capsule is an effective barrier against the passage of larger molecules follows from the fact that the eye does not become sensitized to its own highly antigenic lens proteins except under pathological conditions. Further, sensitization of experimental animals with homologous or heterologous lens proteins failed to produce cataracts, even though lens antibodies were demonstrated in the anterior chamber.1 Yet the capsule contains proteins and polysaccharides, and it therefore becomes a potential antigen when the lens is transplanted. If