MUCOUS GLANDS. 73 



diameter, and in the colon from the ^th to the 5 s th. He 

 estimates the whole number of follicles in the stomach and 

 intestines, at forty-six millions, nine hundred thousand, and 

 upwards. Of these there belong to the stomach, one million, 

 two hundred and ninety-six thousand ; to the small intestines, 

 thirty-six millions, and to the colon, nine millions, six hundred 

 and twenty thousand. And to the inch square, in the sto- 

 mach, fourteen thousand four hundred, in the small intestines, 

 twenty-five thousand, and in the colon, nineteen thousand, two 

 hundred. 



The mucous glands, compared with the follicles or cryptae, 

 are generally of considerable size, and visible to the naked eye;, 

 and in fact appear only to be compound cryptae. They are 

 little bodies placed in the submucous cellular tissue, appearing 

 slightly lobulated when examined with the microscope, and 

 containing minute cells, lined by a reflection of the mucous 

 membrane. These are found most abundant in parts of the 

 mucous membrane, where, from its exposure to acrid or irrita- 

 ting substances, the membrane would appear to need the most 

 protection from the mucous coating ; as in the mouth, the duo- 

 denum and the rectum. 



These glands have already been described in the trachea 

 bronchia, etc. They bear names in many places according to 

 their location, as labial, buccal, palatal, oesophageal, and duo- 

 denal. In the duodenum, of all places, they are most abun- 

 dant where the acrid and irritating biliary secretion first comes 

 in contact with the mucous membrane of the alimentary canal. 

 To these duodenal glands alone, properly belong the term of 

 glands of Brunner. This anatomist (Brunner) was the first 

 to point them out in the mucous membrane of the duodenum, 

 as a series of flattened glandular granulations, studding thickly 

 the upper half or two-thirds of this membrane, and being as 

 he believed analogous in structure to the granular acini of the 

 pancreas. He considered them also similar in structure to the 

 solitary glands ; but in this respect he has been proved wrong. 

 Cruveilhier has observed the analogy of these glands of Brun- 

 ner or duodenal glands, not only with the acini of the pancreas, 



VOL. II. 7 



