X-Ray Microscopy

Injuries were made in rabbit corneas 4-48 hours before tritium-labelled thymidine were injected. Only the injured cells picked up the thymidine. Injured lens cells of rats, rabbits and frogs incorporated thymidine within 14-16 hours with increasing numbers up to 32 hours. Cysteine which stops mitosis for four days, was definitely found to protect lens cells from radiation damage, particularly when a lens was partially shielded. There are discussions of molecular structure in lens fibers with elaborate interlacing borders and of developing specific antigens in chick lenses beginning in the presumtive lens ectoderm. Apparently alpha-cristalin increases in amount with addition of new antigens during development. Immuno-electrophoretic analysis in many different vertebrate lenses show that components of lens specificity, common among different vertebrates, diminish down the phylogenetic scale into the invertebrates. There is also a review of the complicated subject dealing with factors which bring about ocular malformations. L. S. STONE