THE GLANDS OF THE INTESTINE 



277 



as if cells of the mucous membrane perish in great numbers, even if, as in this 

 case, no food or anything of the kind comes into the intestine. Nevertheless, 

 this conclusion is not quite definitely established, for it cannot be maintained 

 that the isolated loop is in a perfectly normal condition. And, in fact, Klecki 

 has observed that if he washed the intestinal ring tolerably free of Bacteria 

 with boracic acid and artificial gastric juice before sewing it up, and if in the 

 further course of the experiment no pathological changes of any kind made 

 their appearance, he found after the lapse of more than two months only a 

 scanty deposit of yellowish, sticky, waxlike substance adherent to the surface of 

 the membrane. This, like the contents mentioned above, consisted mainly of 

 desquamated intestinal epithelial cells, 

 but was by no means so abundant. 



Histological studies of the glands 

 of Lieberkiihn have shown that their 

 fundic cells have the same morpho- 

 logical character as the cells of the 

 other digestive glands. Likewise in 

 these the preliminary stages of the 

 secretion appear in the form of gran- 

 ules which gradually increase in size 

 and finally pass over into the secretion. 

 These cells are very sharply distin- 

 guished by their properties from the 

 mucous cells (goblet cells) of the 

 intestinal epithelium (W. Holier). 



FIG. 111. Glands of the large intestine of 

 the rabbit, after Heidenhain. A, after 

 very active secretion; B, after a long 

 period of rest. 



B. THE GLANDS OF THE LARGE 

 INTESTINE 



The glands of Lieberkiihn in the 

 Jorge intestine do not secrete a digest- 

 ive fluid. The properties of their 

 secretion have been studied by mak- 

 ing an opening into the large intes- 

 tine and introducing various sub- 

 stances inclosed in small sacs of 

 network. It has been found in this way that neither fibrin nor starch is 

 digested. The secretion, which is but scanty, is a water-clear, odorless, thickly 

 gelatinous and sticky mass of neutral reaction, containing turbid flakes of 

 various sizes (Klug and Koreck). 



The secretion of the large intestine, therefore, plays no part in digestion. 

 The mucus contained in it probably serves to facilitate the passage of the 

 intestinal contents which have become thicker by the absorption of water. 



If the mucous membrane of the large intestine be studied under the micro- 

 scope, after injection of pilocarpine into the animal, the glands are seen to 

 be composed of cells which are strikingly like those of the glands in the small 

 intestine. In alcoholic preparations the cells of both are small, longitudinally 

 striated, and contain round or oval nuclei (Fig. Ill, A). After prolonged 

 rest the glands of the large intestine present quite another picture. The 



