ABSTRACT
Formerly, many embryologists believed that the blastema cells in regenerating amphibian tails and limbs arose from a reserve of undifferentiated cells, but since the work of Hertwig (1927) and Butler (1935) few modern investigators would support this view. Others have suggested that blastema cells are of epidermal origin (Godlewski, 1928; Rose, 1948). However, this idea has largely fallen into disrepute following the investigations of Karczmar & Berg (1951), Chalkley (1954) and Hay & Fischman (1961). There is now abundant evidence that blastema cells arise by the dedifferentiation of some of the stump tissues, in particular the stump muscle and cartilage (Thornton, 1938 a, b;, Hay, 1958,1959, 1962; Hay & Fischman, 1961), and that contributions may also arise from fibroblasts when they are present.
