A Complete Reconstruction of the Neural Retina of Chick Embryo Grafted Onto the Chorio-Allantoic Membrane

When dissociated neural retinal cells of 6-to 10-day-old chick embryos were grafted as a pellet onto the chorio-allantoic membrane and allowed to develop, complete retinal structures were reconstructed. Especially when the retinal cells of 6-day-old embryos were used, well orientated retinal structures, which possesed three nuclear layers and two plexiform layers, were formed. The fundamental steps in this complete reconstruction were as follows; rosette formation, formation of a fibrillar lumen, differentiation of receptor and ganglion cells, fusion of the fibrillar lumen, fusion of the receptor lumen and finally the formation of a three-layered neural retina. Reconstruction by the retinal cells of older embryos was less complete. This stagedependent difference in the capacity for reconstruction was due to a difference in the ability to form well developed rosettes at an early phase of the process of reconstruction.