SURGICA. EALINc is considered to have occurred when tissue continuity has been restored, following wounding, to a strength approximating normal tissue strength and when the wound defect has been appro-priately surfaced. Restoration of the organism's surface is accomplished by a complex activity of epithelial and connective tissues. Restoration of continuity and strength, whatever the tissue involved, results from fibroplasia. Biochemical understanding of fibrogenesis is increasing rapidly. Mechanisms regulating the proliferation of fibroblasts and their productivity remain largely unknown, however. The origin of these fibroblasts, the basic cells of wound repair, is still controversial. Recent investigations have supported both vascular and local origin of these cells.******* The present experimental study explored the question of the predominant site of origin of fibroblasts. Earlier experiments demonstrated the inhibitory effect of x-irradiation on proliferation of new connective tissue varying with