CHANGES Or FOOD IN THE ALIMENTARY CANAL. 



41.5 



almost entirely composed of a multitude of parallel tubuli closely applied to 

 each other, their caecal extremities abutting against the submucous tissue, and 

 their open ends being directed towards the cavity of the stomach. The con- 

 formation of these tubuli is not the same, however, in every part; for whilst 

 they are usually straight and simple, especially in the cardiac portion of the 

 stomach, they are longer and more complicated in the neighborhood of the 

 pylorus, their deeper parts presenting a sacculated or somewhat convoluted 

 appearance (Fig. 122). Between the tubuli, bloodvessels pass up from the sub- 

 mucous tissue, and form a vascular network on its surface, in the interspaces 

 of which the orifices of the tubes are seen (Fig. 126). From the examination 



Fig. 122. 



Section of the Mucous 

 Membrane of the Stomach, 

 near the pylorus, showing 

 the Gastric Follicles: 1, 

 magnified 3 times ; 2, mag- 

 nified 20 times. 



Fig. 123. 



A. Horizontal section of a stomach-cell, a little 

 way within its orifice, a. Basement membrane, b. 

 Columnar epithelium. All but the centre of the 

 cavity of the cell is occupied by transparent mucus, 

 which seems to have oozed from the open extremi- 

 ties of the epithelial particles, c. Fibrous matrix 

 surrounding and supporting the basement mem- 

 brane, d. Small bloodvessel. 



B. Horizontal section of a set of stomach tubes 

 proceeding from a single cell. The letters refer to 

 corresponding parts. The epithelium is glandular ; 

 the nuclei very delicate ; the cavity of the tubes 

 very small, and in some cases not visible. 



From the dog, after twelve hours' fasting. Mag- 

 nified 200 diameters. 



of horizontal sections of the Mucous membrane at different depths, Dr. Todd 

 has ascertained that the tubuli are arranged in bundles or groups, surrounded 

 and bound together by areolar tissue; the size of the bundles, however, and the 

 number of tubules contained in them, vary considerably. The character of the 

 internal surface of the stomach, and the mode in which the tubuli open upon it, 

 are by no means the same in different parts of the organ. When a well-injected 

 preparation is examined with the microscope, it is seen that on the convex sur- 



