. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 350 STOMACH AND INTESTINE. laries of the neighbouring villi. And the venous radicles of these latter processes usually unite with the branches formed by their con-. for the most part disappears ; and the villi, which are still more or less flattened, have about twice the length, and half the width, of those present in the upper part. But it is in the upper part of the jejunum that the}' attain their greatest number; being placed so closely together that their interstices scarcely Fig. 259. Capillaries occupying the surfa
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. 350 STOMACH AND INTESTINE. laries of the neighbouring villi. And the venous radicles of these latter processes usually unite with the branches formed by their con-. for the most part disappears ; and the villi, which are still more or less flattened, have about twice the length, and half the width, of those present in the upper part. But it is in the upper part of the jejunum that the}' attain their greatest number; being placed so closely together that their interstices scarcely Fig. 259. Capillaries occupying the surface of the mucous mem- brane of the small intestine; as seen on examining an injected specimen by reflected light, with a mag- nifying power of about 50 diameters. a, b, capillaries around the orifices of the intes- tinal tubes. At a their meshes are more numerous and complex than at b, where they are almost re- duced to single capillaries; c, calibre or cavity of the intestinal tube. flux in a small vein; that sinks vertically through the mucous membrane, to .join the sub-mucous plexus which gives origin to the portal vein. Villi. — The interior of almost all the small intestine presents to the naked eye a texture very like that of velvet. For it is soft and shaggy: yields readily to pressure : and, on close examination, is evidently composed of innumerable short filaments, which are placed more or less vertically to the general inner sur- face of the tube. These filaments, — the dense arrangement of which on a common surface causes this general velvety appearance,— are thence usually named villi. Their form, and their situation, or office, might also be denoted b}' the name of intestinal or chyliferous papillce. We have seen that, in the stomach, the con- fluent ridges intervening between the tubes are here and there raised into slight projec- tions. These are rendered more prominent by artificial injection of the subjacent vessels, or even by that afflux of blood which
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