66 PRACTICAL HISTOLOGY. 



STOMACH. 



PREPARATION. Open the stomach of a cat, dog, or rabbit, and wash away the layer of 

 mucus lining it with a stream of salt solution. 



(a) Harden small pieces of the pyloric and cardiac ends and middle of the stomach for 

 two weeks in the chromic acid and spirit fluid (p. xxxi). Complete the hardening in spirit. 

 Make vertical sections of each piece. Stain sections with logwood, and mount them in 

 dammar, and others with picrocarmine, and mount them in Farrant's solution. 



(b) After washing out a stomach of any of the above animals with salt solution, distend it 

 with and place it in absolute alcohol or merely small pieces may be hardened in absolute 

 alcohol. These show gland-structure well, and stain readily. 



(c) Very small pieces, not larger than a pea, are to be hardened in a quarter per cent, 

 osmic acid for twenty-four hours. Make sections and mount them in Farrant's solution. 



CARDIAC END OF STOMACH. 



Vertical Section. (Logwood and dammar.) EXAMINATION (L). Observe the mucous 

 coat with its gastric glands placed vertically. Trace a gland and note whether it branches 

 below or not. The bases of the gland rest on a small amount of connective tissue, which 

 sends up processes between the glands. Immediately outside this lies the muscularis mucosae, 

 which consists of two layers longitudinal and circular and sends processes upwards be- 

 tween the glands. (Indicate this general arrangement in PL XIII., Fig. 2.) 



The sub-mucous coat composed of connective tissue containing blood and lymph-vessels, 

 fat-cells, and nerves. The muscular coat, consisting of two coats, with perhaps a third. The 

 appearance of these coats varies according to the plane of their section ; and outside this, the 

 serous layer, or peritoneum. If the stomach of the cat be selected, a clear band of condensed 

 connective tissue will be observed lying immediately above the muscularis mucosae. This 

 preparation shows well the passage of the muscularis mucosae fibres upwards between the 

 glands. 



To see the finer details of structure study the preparation mounted in Farrant's solution. 

 (L). Observe the same general arrangement as before. (H). Study & peptic gland. Note the 

 clear, tall, narrow, columnar epithelium lining the stomach, and continued some distance into 

 it. The nuclei of the cells are placed near their attached ends. The cells appear in some 

 cases to be open at their free ends, especially if the animal be killed during digestion, and 

 are, in fact, mucus-secreting goblet-cells. Note that the lower part of the cell is always 

 granular, even though the upper two-thirds be quite transparent. In the middle and lower 

 part of the gland note the coarsely granular nucleated outer, ovoid, or peptic cells, which 

 frequently cause a bulging on the side of the gland ; and, internal to these, small ill-defined 

 inner or central cells, best seen at the lower part of the gland. A small narrow lumen may be 

 detected in the gland. The cells most deeply stained are the ovoid cells. Study the mus- 

 cularis mucosae, and note that it consists of two sometimes three layers of non-striped 

 muscle, and trace processes from it upwards between the gland. 



Transverse sections of the glands are to be met with in the same section. They are 

 usually in groups of four or five, and separated by a little connective tissue and a few non- 



