XXIV.] THE STOMACH. 



fixing the cells of the glands of the mucous membrane (mount in 

 Farrant's solution). In sections of the fundus, the outer cells are 

 more deeply stained, and so are readily distinguished. The columnar 

 cells lining the ducts of the cardiac and pylofic glands may be 

 blackened by the osmic acid where they contain mucigen. 



6. Blood- Vessels of the Stomach. Make Y.S. of an injected 

 stomach embedded in paraffin. Mount in balsam. They must not 

 be too thin. Note the large vessels in the submucous coat, and 

 from them smaller vessels proceeding vertically upwards, splitting 

 up into capillaries between the tubules, and forming a capillary 

 network round the mouths of the glands. Beautiful plates by Mall. 1 



7. Pyloro-Duodenal Mucous Membrane. It is well to have a 

 section through the pyloric valve to include the mucous membrane 

 on its gastric and duodenal boundaries. To ensure this, the mucous 

 membrane or entire thickness of the stomach must be pinned out 

 on cork before it is hardened by any of the methods, e.y. t sublimate 

 (p. 267). It is treated like the sections of the stomach, and does 

 best when stained with eosin-hsematoxylin. On one side of the 

 thickened pyloric valve the increased thickness being due chiefly 

 to an increase of the circular muscular fibres one sees the pyloric 

 structure, and on the other that of the duodenum. The tubular 

 glands of the stomach are confined to the mucous membrane, but 

 the acini of Brunner's glands lie in the submucous coat of the 

 duodenum. 



8. Junction of (Esophagus and Stomach. Similar preparations 

 may be made. The transition from the cesophageal mucous mem- 

 brane with stratified epithelium and few glands in the oesophagus 

 to that of the stomach with its columnar epithelium and mucous 

 glands is sudden and abrupt. 



ADDITIONAL EXERCISES. 



9. Double-Staining the Stomach. Harden the stomach in Miiller's fluid, 

 and stain (24 hours) the sections in indigo-carmine (p. 67) ; afterwards extract 1 

 the excess of pigment by steeping them for half an liour in a saturated solution 

 of oxalic acid. Mount in Farrant's solution or balsam. The parietal cells aro 

 grey or blue, the central ones coloured, but with red nuclei, and the smooth 

 muscle blue with red nuclei. 



10. Ehrlich-Biondi Fluid. Stain in this fluid sections of the mucous meni' 

 brane fixed in sublimate (saturated in .6 per cent. NaCl). If the fluid be kept 

 for some time, an additional quantity of acid-fuchsin must be added to it. 

 The parietal cells are red and their nuclei bine ; the chief cells are scarce!) 

 stained at all, but their nuclei are faintly blue. Yacuoles may be seen in some 

 of the outer colls. 



11. Aniline-blue and Safranin. Sections of the cardiac end fixed in 



J Vessels and Walls of Dog's Stomach, John* 7/^>/.-///.v Ifosp. Rrp., vol. i. 1893. 



