Transfer of the primary induction stimulus by small numbers of amphibian ectoderm cells.
D000818:Animals; D001345:Autoradiography; D002454:Cell Differentiation; D004475:Ectoderm / Q000502:physiology*; D066298:In Vitro Techniques; D009417:Nerve Tissue; D009420:Nervous System / Q000196:embryology*; D014316:Tritium; D014981:Xenopus / Q000196:embryology*
D014316:Tritium