Understanding of the biochemistry of fibrogenesis in wound repair has increased steadily. Recent advances in knowledge of this process have been reviewed by Grillo,21 Harkness,24 and Jackson,31 among others. Correspondingly little increment had occurred in comprehension of the mechanisms of cellular stimulation prior to beginning of fibrogenesis or of regulation of proliferation and productivity of cells thereafter. Recently there has been renewed interest in an early phase of this problem—the question of site of origin of fibroblasts in wound repair. New contributions are reviewed against the background of the ancient and continuing controversy over histogenous against vascular derivation of fibroblasts. Origins of Controversy Virchow's belief in the immutable lineage of cells found expression in the assertions by Marchand 38 and Aschoff 4 on histologic grounds that fibroblasts in wound healing were derived from the connective tissues of the wound. Maximow, however, studying fixed sections of inflammatory exudate