Indirect staining method of Weller and Coons [23] was applied to detect the presence of FISC and α-crystallin lens antigens in the embryonic and post-embryonic chick lenses. Specific antiserum against these 2 antigens was prepared by a method of immunological tolerance in new born rabbits. Earliest reactions against either of the 2 antisera were not restricted to few cells only as has been reported earlier. The central non-nucleated fiber area, the so-called lens nucleus, from a 6-week-old chick lens gave negative immuno-fluorescence reactions against both the antisera, but presence of these 2 antigens in the nuclear region could be detected by immuno-electrophoresis