Spemann's organizer and the formative cells.
The events which happen after transplantation of organizer material into a Triton germ are explained by the action of formative cells. As example the first steps of in vitro mesonephrogenesis are filmed. The sequences show that the locomotion of the relatively sluggish epithelial cells is accomplished by the activity of fibroblasts.
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D000818:Animals; D002450:Cell Communication; D002465:Cell Movement; D002478:Cells, Cultured; D002642:Chick Embryo; D005314:Embryonic and Fetal Development; D005347:Fibroblasts / Q000502:physiology*; D008650:Mesonephros / Q000166:cytology / Q000196:embryology*; D009024:Morphogenesis; D009040:Motion Pictures; D010784:Photomicrography