Morphogenetic Interaction between Embryonic Mouse Tissues separated by a Membrane Filter

IN analysing inductive interaction between parts of developing systems several investigators1 have interposed barriers of various sorts to distinguish between effects due to direct cellular contact and those due to diffusion. No morphogenetic effect has been demonstrable in particular cases through ‘Cellophane’, vitelline membrane or cigarette paper. In studies of epithelio-mesenchymal interaction in cultured mouse embryo rudiments we have, recently employed so-called membrane or molecular filters2 for similar purposes and have noted two morphogenetic effects across them. The present brief report is to record these results as a suggestion of possible broader usefulness of filters of this type in problems of embryonic induction.