The importance of the apposition of the submucosal layers in healing of the intestinal anastomosis was examined. On 18 mongrel dogs, weighing between 8-15 kg, 4 anastomoses were performed on the small intentine. Two with a conventional anastomosis and 2 with rings of polyester-polyethyleneterephthalate, containing small Ticonal magnets. The force between the rings with the magnets varied from 0-3 N between, respectively, 15 mm and O mm distance. After 3-4 days, the rings cut through and disappeared from the anastomosis. Morphologic and microangiographic studies, undertaken at 10 days, revealed that in instances of good submucosal apposition, direct bridging of the defect in the submucosal layer was seen with rapid restoration of the villous epithelium and an undisturbed vascular pattern in the anastomotic area. This was called primary intestinal healing. In instances of bad submucosal apposition, an indirect bridging of the submucosal layer defect by smaller and longer strands of newly synthesized collagen tissue in the outer intestinal layers with a collateral circulation from the submucosal plexus to the arterial plexuses in these layers was seen. An epithelial defect still persisted at 10 days. This type of wound healing was called secondary intestinal healing. With the magnetic rings, a significantly better apposition of the intestinal layers was achieved.