STRUCTURE OF THE PANCREAS. 



229 



From the above considerations the intestinal juice must be 

 regarded as possessing some digestive action upon the food-stuffs, 

 its most marked property being its power of inversion. It is 



FIG. 124. A solitary lymph-nodule from the human colon : at a, is seen the pro- 

 nounced concentric arrangement of the lymph-cells (Bohni and Davidoff). 



not an abundant secretion, and one of its important offices is, 

 doubtless, to lubricate the mucous membrane of the small in- 

 testine. 



THE PANCREAS. 



Structure of the Pancreas. This organ is a gland of the 

 tubulo-racemose type, and, from its resemblance to the salivary 

 glands, is described as the abdominal salivary gland ; the pancre- 

 atic alveoli are, however, longer and more tubular. Its location 

 is in the abdominal cavity, behind the stomach and between the 

 duodenum and the spleen. Its length is from 15 to 23 cm., its 

 width about 4.5 cm., and its thickness 2.8 cm. The alveoli are 

 lined with columnar or polyhedral cells, which, in the fresh con- 

 dition, contain small granules in the protoplasm of their inner 

 two-thirds, while that of the outer third is clear. This clear 

 portion becomes larger, encroaching upon the granular part, when 

 the gland is active. 



The changes which these cells undergo may be more distinctly 

 shown by means of carmine, which acts as a staining agent. Thus 

 Fig. 125 represents the appearance of the cells of a pancreas 

 which was removed from a dog that had fasted for twenty-four 

 hours. 



