474 MANUAL OF HISTOLOGY. 



membranes of this kind (p. 226) ; the muscular substance, consisting of 

 longitudinal, transverse, and oblique fibres, belongs to the involuntary 

 species (163). 



The mucous membrane of the stomach is clothed from the cardiac 

 orifice on (where the flattened epithelium of the oesophagus terminates 

 with an irregular boundary line) with columnar epithelium ( 91), which 

 is continuous from that point on throughout the whole extent of the intes- 

 tinal tube. The cells are of the long and narrow species (about 0-6323- 

 0-6226 mm. in length and 0-0045-0-0056 in breadth). In profile they 

 are seen to possess a cell-membrane, of which the free base of many of 

 them is probably quite destitute during life (Schulze). Younger and 

 smaller epithelial elements may also be seen between the undermost 

 pointed extremities of these cylinders. 



The surface of the gastric mucous membrane is by no means smooth, 

 but on the contrary very uneven, with prominences varying in height from 

 0-0751 to 0-1128 and 0'2 mm. The latter possess either a tuft-like form 

 or that of intersecting folds, bounding a multitude of smaller or larger 

 depressions into which the peptic glands discharge their contents. 

 Orifices at the summits of these eminences, on the other hand, never 

 occur. There is much variety, as regards these points, both in different 

 animals and localities. 



Still more considerable eminences of this kind are to be found at the 

 pyloric end of the stomach, where, as a rule, the mucous membrane attains 

 its greatest thickness, measuring up to 2 mm. in depth. Towards the 

 cardiac end, on the other hand, where the surface is smoother, the 

 membrane decreases greatly in depth, falling down to from 1-1128 to 

 0-5640 mm. 



The proper tissue of the mucous membrane is, owing to the enormous 



number of glands imbedded in it, 

 but very scanty. As a rule, it pre- 

 sents itself in the form of a soft 

 nucleated connective-tissue of loose 

 texture (fig. 454). It varies, how- 

 ever, considerably in different classes 

 of animals. Beneath the glandular 

 layer is situated a stratum about 

 0-0564 or 0-1128 mm. in thickness, 



Fig. 454. Transverse section through the gas- Consisting of fibrOUS Connective-tissue 

 trie mucous membrane of the rabbit. , an( J intersecting muscle fibres. Ill 

 tissue of the mucous membrane; 6, transverse . i 



sections of empty and injected biood-vesseis ; this two layers may be recognised an 



d.openingswherepepticglandsweresituated. internalj f ormed pr i nc i pa ll v O f trailS- 



verse fibres, and an external or longitudinal coat. The relative thickness 

 of these two layers varies greatly in different portions of the stomach 

 (Schwartz). Then from this laminated muscular substance there ascend 

 email bundles of contractile fibre-cells between the glandular follicles. 

 These musculares mucosce, whose beginnings we have already seen in the 

 oesophagus, persist now from this on, with certain variation of arrange- 

 ment as might be supposed, and form integral elements of the digestive 

 mucous membrane. 



This constitution, however, of the mucous membrane may give 

 way to another. There may appear, namely, between the bands of 

 connective -tissue a greater or smaller number of lymph -corpuscles, 

 pointing to an intermediate form of tissue between that of the gastric 



