Abstract
Chick retinal cells of different stages of development, and of different areas of the retina, were stained with two vital fluorescent stains, reaggregated, and analysed for sorting-out. Sorting-out of cells within aggregates occurred if one cell sample was derived from the retinae before and the other after day 7 of incubation. No such cell-sorting effects were found in experiments performed on cells of different areas at the same stage. It is suggested that the sorting-out reflects either a change in cell population around day 7 (such as an increase in postmitotic neuronal cells), or the effect of a stage specific signal which changes the surface properties of a substantial part of most or all cell types.
