Abstract

Embryonic and adult field do not exhibit the same properties because they are formed by cell populations whose activities cannot be compared in all respects. Dominant cells are not distributed in the same manner; the same mechanisms are not involved for remodelling of the field, especially after an amputation.In adult organisms, cell equilibrium is disturbed a first time by elimination of differentiated tissues which provokes dedifferentiation and proliferation, and a second time by healing, which restores cell equilibrium of a distal end. Undifferentiated cells begin to differentiate immediately after their production and they reform the missing levels, following a sequence either basipetal or basifugal according to the place of their production . The differentiating regenerate temporarily exhibits embryonic field properties in various experimental conditions which suppress the dominance of the stump or supplies additional undifferentiated material