068 



OF SECRETION. 



[Fig. 274. 



the pylorus. When the surface of the membrane, cleansed from mucus and 

 epithelium-scales, is examined with a sufficient magnifying power, it is seen 

 that from three to five perforations exist in the bottom of each pit ; and these 

 are the openings of the secreting tubes. The Gastric fluid, elaborated by this 

 apparatus, having been already made a subject of special consideration ( 664) 

 need not be here described. 



874. The whole Mucous sur- 

 face of the Intestinal canal is fur- 

 nished with glandular follicles of 

 a very similar character; of which 

 some approach those of the sto- 

 mach in complexity of structure; 

 whilst others evidently corre- 

 spond with the crypts of ordinary 

 Mucous Membrane. An innu- 

 merable multitude of pores are 

 easily seen, by the aid of a sim- 

 ple lens, to cover the whole in- 

 ternal surface of the large Intes- 

 tine ; and these are the entrances 

 to tubular follicles, closely resem- 

 bling those of the stomach, but 

 more simple in structure. Their 

 coecal extremities abut against the 

 sub-mucous tissue : towards the 

 end of the Rectum, however, 

 they are much prolonged, and 

 constitute a peculiar layer be- 

 tween the mucous and muscular 

 coats ; the tubes which are there 

 visible to the naked eye, being 

 erect, parallel, and densely crowd- 

 ed. These glands probably form 

 the peculiarly thick and tenacious 

 mucus of the large intestine. In 

 the small intestine, on the other 

 hand, the cceca are less deep and 

 their apertures are smaller. These 

 apertures are, for the most part, 

 situated around the bases of the 

 villi : in the fetus and newly-born child, they are so abundant as to be almost 



A section of the Ileum, inverted so as to show the ap- 

 pearance and arrangement of the villi on an extended 

 surface, as well as the follicles of Lieberkiilm ; the whole 

 seen under the microscope. A close examination of this 

 cut will show a great number of black points in the 

 spaces between the projections of villi : these are the 

 follicles of Lieberkiihn.] 



Fig. 275. 



Fit:. 276. 



One of the glandulrc majores sim- 

 plices, viewed from above at A, and 

 seen in section at B ; from the large 

 intestine. 



Mucous coat of small intestines as 

 altered in fever; the follicles of Lie- 

 berktihn filled with tenacious white 

 secretion. 



