33° 



GLANDS OF THE SMALL INTESTINE. [sect. 1 54. 



one or more large globules of firm and of fluid fat, winch, according to 

 Bonders, arise from a separation of the fat which has penetrated taking 

 place after death. The smaller cells, described by E. H. Weber as being 

 under the epithelial cells, have no existence. 



§ 154. Glands of the small Intestine. — The small intestine con- 

 tains only two kinds of true glands, viz., 1. tubular, which exist 

 everywhere in the mucous membrane ; and 2, racemose, seated in 

 the submucous tissue. 



The racemose, or the glands of Brunner, form, at the commence- 

 ment of the duodenum, on the outer side of the mucous membrane, 

 a continuous glandular layer, which is most developed and dense 

 close to the pylorus, so that here they give rise to a glandular 

 ring, which extends as far as the opening of the gall-duct. If, in a 

 distended duodenum, the two layers of the muscular coat have been 

 dissected off, the glands are readily recognised as yellowish, rounded 

 angular, flattened bodies, -f~" to \\"' , or, on an average, £'" to \ m 

 in diameter, which, enveloped in some areolar tissue, are seated 

 close to the mucous membrane, and send off short excretory 

 ducts into it. With reference to their intimate structure, the 

 glands of Brunner, whose terminal vesicles measure 0'03'" to 

 o , o6'", or even o'o8'" in diameter, entirely agree with the racemose 

 glands of the oral cavity and oesophagus. Their secretion is an 

 alkaline mucus, without morphological elements, which exerts no 



digestive action upon coagulated protein com- 

 pounds, and probably subserves mere me- 

 chanical purposes. 



The tubular or Lieberkiihnian glands are 

 found distributed over the whole small intes- 

 tine and duodenum as very numerous, straight 

 and narrow tubes, extending through the entire 

 thickness of the mucous membrane. At the 

 extremity they are slightly swollen, but very 

 seldom bifurcated (but in animals, they are 

 frequently bifid or trifid). An idea of their 

 number may be best obtained when the mu- 

 cous membrane is examined in perpendicular 

 sections, or from above, by low magnifying 

 powers. In the first case, we see tube upon 

 tube, almost without any interspaces, arranged 

 closely together like palisades (fig. 141) ; in 



Fig. 141. 





Lieberkiihnian glands of 

 the pig; magnified GO times. 

 a. memhrana propria and 

 epithelium ; b. cavity. 



