194 DIGESTION. [CHAP. xxiv. 



with that laxer stratum which separates the mucous from the mus- 

 cular coat. 



The stomach tubes have a basement membrane, and contain an 

 epithelium altogether different from that which has been just de- 

 scribed. Its particles are of the glandular variety, are rounded in 

 shape, without obvious walls; their contents are darkly granular, 

 often mixed with oil globules, and their nucleus is less distinct. The 

 tubes are so narrow that the particles seem to fill them, and oblite- 

 rate their cavity, except near their orifices, where they empty them- 

 selves into the cells. Towards their blind extremities they often 

 seem to be simply a series or pile of epithelial particles ; and this 

 has led some anatomists to deny that they are tubes. The existence, 

 however, of a basement membrane convinces us that they are to be 

 regarded truly as tubes, permanently laid down in the tissue of the 

 stomach, for the origination and discharge of the materials of their 

 peculiar epithelial particles on its inner surface. The tubes proceed 

 in sets, corresponding to the cells into which they open; those of 

 each set being enclosed in a common envelope of nucleated tissue, 

 like the matrix of the kidney and some other glands. This firm 

 investing structure is attached on the one hand to the dense layer on 

 which the compound membrane rests, and on the other to the ridges 

 between the cells ; and it sends delicate processes between the indi- 

 vidual tubules of each set, and between their branchings, so as to 

 sustain every portion in its proper place. Between the sets of 

 tubules the larger vessels run up to the ridges between the cells, 

 and every tubule is invested with capillaries, which take for the 

 most part an upward direction, and are cut across with the tubules 

 in a transverse section of the latter, (fig. 155, B, d.) We have met 

 with no tubular nerve fibres in the mucous membrane of the sto- 

 mach ; but it is highly probable that nucleated nerve fibres run 

 among the tubes, though their want of characteristic features ren- 

 ders it difficult to positively assert their presence. 



The description now given will hold good for the whole lining of 

 the stomach, except near the pylorus. Here, in many of the lower 

 animals which we have examined, for example, in the dog, and, it 

 may with probability be inferred, in man also, a change occurs in a 

 very gradual manner, but evidently of an important kind. The mem- 

 brane is of a paler tint, and its cells seem not to terminate at once 

 in the true stomach tubes already described, but are prolonged into 

 much wider cylindrical tubes, lined with the same columnar epi- 

 thelium, and descending nearly or altogether to the deeper sur- 

 face of the compound membrane. For the most part, these prolong- 



