Morphology of lymphatics in the canine large intestine.

The finer distribution of lymphatics in the large intestine of adult dogs was morphologically examined by puncture injection of colored dyes, intra-arterial injection of silver nitrate mixed with India ink, and electron microscopy. In the lamina propria there was a double-layer of lymphatic channels - a shallow network (near the mucosal surface) and a deep compartment (just above the muscularis mucosae). Sparse lymph capillaries also extended vertically paralleling intestinal glands. Some lymphatics penetrated into the submucosa where they demonstrated prominent valves and formed collecting lymphatic trunks alongside blood vessels.