[Hyperproduction of the epithelium and its vital rejection in the lumen of the small intestine outside the "rejection zone"].

Whole and histologically-treated biopsy material of the small intestinal mucosa of dogs with a full intestinal fistulae and of dogs with a portion of the small intestine excluded from digestion was studied. An intensive production of the surplus epithelial structures (protrusions, layers) was revealed in the areas of the crypts and the base of the villi. Rejection of these structures into the intestinal lumen occurred outside the "expulsion zone" with the preservation of the intactness of the villar surface. Less marked signs of this process were seen in control material. The data obtained testify to the fact of the existence of another way of development of the crypt cell leaving the crypt-villus system in the composition of the branching and rejecting epithelial structures.