522 



DIGESTION. 



Fig. 221. length from one-fourth of a line to nearly a line. They 

 are longer and more closely set towards the pylorus than 

 elsewhere, their length being equal to the thickness of 

 the mucous membrane of the stomach, which varies. 



The office of these tubular follicles, it has been thought, 

 is to secrete the gastric fluid, during digestion ; for in the 

 intervals they are at rest. They are formed by inflections 

 of basement membrane, with cylindrical epithelium rest- 

 ing upon it. One of them is represented in the marginal 

 figure, which exhibits the nucleated cells at the bottom 

 of the follicle; becoming more and more developed as 

 they approach the free surface. These cells prepare 

 the gastric fluid, and ultimately burst and discharge it 

 to become mixed with the aliment in the stomach. 



Besides these glands or follicles, small opaque white 

 sacculi, resembling Peyer's glands, are met with, which 

 Tubular Follicle of are fiHed with minute cells and granules. They are 



Pig s Stomach. . , . a , , ^ , 



(After Wasmann.) situate chiefly along the lesser curvature of the stomach 



Fig. 222. 



Fig. 223. 



B 



Vertical Section of a Stomach Cell, with 

 its Tubes. 



A. In the middle region. B. In the pyloric 

 region, a, a. OrificeB of the cells on the 

 inner surface of the stomach. 6, b. Different 

 depths at which the columnar epithelium is 

 exchanged for glandular, c. Pyloric tube, 

 or prolonged stomach cell. d. Pyloric tubes, 

 terminating variously, and lined to their ex- 

 tremities with sub-columnar epithelium. 



From the dog, after twelve hours' fasting, 

 Magnified 200 diameters. 



Mucous Membrane of the Stomach. 



A. Inner surface of the stomach, showing 

 the cells after the mucus has been washed 

 out. Magnified 25 diameters. 



B. Columnar epithelium of the inner sur- 

 face and cells of the stomach, a. Free ends 

 of the epithelial particles, seen on looking 

 down upon the membrane, b. Nuclei visible 

 at a deeper level, c. The free ends seen 

 obliquely, d. Deep or attached ends of the 

 same. The oval nuclei are seen near the 

 deeper ends. 



From the dog. Magnified 300 diameters. 



