THE SPLEEN. 1073 



with one of the ramifications of the main duct (Fig. 685). This interalveolar 

 connective tissue supports the blood-vessels, and in certain parts of it are seen 

 collections of cells, interalveolar cell-islets. They are permeated by a network of 

 capillaries, and are very characteristic of the pancreas. Their function is un- 

 known. The minute ducts are lined by short columnar epithelium, shorter than 

 that found in the salivary ducts, and with no striation. The alveoli are tubular, 



/ ' 



wavy, and convoluted, lined by columnar cells which presents two zones: an 

 outer one presenting the nucleus, clear and faintly striated ; and an inner granu- 

 lar one, next the lumen. These are the secreting cells ; after their activity the 

 granular zone occupies most of the cell, whereas, in the earliest stage of digestion, 

 the clear zone did this. The lumen of the alveolus is hardly visible, being filled 

 by spindle-shaped cells, the centro-acinar cells of Langerhaus. Piersol considers 

 these as imperfectly developed acini, and calls them bodies of Langerhaus. 



The pancreatic duct presents two coats, fibro-elastic and mucous. There is no 

 sign of muscular tissue. Fine intercellular canaliculi have been seen, compar- 

 able to those of the liver, passing from between the cells to the lumen of an 

 alveolus. 



Surface Form. The pancreas lies in front of the second lumbar vertebra, and can some- 

 times be felt, in emaciated subjects, when the stomach and colon are empty, by making deep 

 pressure in the middle line about three inches above the umbilicus. 



Surgical Anatomy. The pancreas presents but little of surgical importance. It is occa- 

 sionally the seat of cancer, which usually affects the bead or duodenal end, and therefore often 

 speedily involves the common bile-duct, leading to persistent jaundice. Cysts are also occasion- 

 ally found in it. which may present in the epigastric region, above and to the right of the umbil- 

 icus, and may require opening and drainage. The fluid in them contains some of the elements 

 of the pancreatic secretion and is very irritating, so that, if allowed to come in contact with the 

 skin of the abdominal wall, it is likely to produce intractable eczema. It has been said that the 

 pancreas is the only abdominal viscus which has never been found in a hernial protrusion ; but 

 even this organ has been found, in company with other viscera, in rare cases of diaphragmatic 

 hernia. The pancreas has been known to become invaginated into the intestine, and portions 

 of the organ have sloughed off. In cases of excision of the pylorus great care must be exer- 

 cised to avoid wounding the pancreas, as the escape of the pancreatic fluid may be attended 

 with serious results. According to Billroth, it is likely, in consequence of its peptonizing quali- 

 ties, to dissolve the cicatrix of the stomach. 



THE SPLEEN. 



The spleen is the largest and most important ductless gland. It is probably 

 related to the vascular system, yet its anatomical relations to the stomach and 

 physiological relation to the liver, may allow it to be described as an accessory to 

 the digestive tract. 



It is placed deep in the left hypochondrium, between the fundus of the stom- 

 ach and diaphragm, above the descending colon. 



In number there is but one, yet various observations show it may be congeni- 

 tally lacking, or may be multiple; as many as twenty-three in one body. These 

 are called accessory or supernumerary spleens (lienculi\ probably occasioned by 

 the deep notching of the anterior margin and separation of the included parts. 

 They may be connected with the mother-organ by thin bridges of splenic tissue 

 or only by a portion of capsule. They are generally wholly isolated, and situ- 

 ated in the gastro-splenic omentum, great omentum, transverse mesocolon, or 

 in the pancreas on a branch of the splenic artery. Frequently, one or two are 

 in the region of the hilus. They are of the size of a hazelnut, red to almost 

 black in color and of a rounded form. 



Xo organ varies more in volume than the spleen. In children it is relatively 

 well developed. In old age it is usually atrophied. It varies with the same 

 individual, w ith sex, degree of fulness of portal vein, state of health or of dis- 

 ease, and with the influence of certain drugs. It is hypertrophied in all infec- 

 tious diseases and in all depending upon malarial poison or leukaemia. It may 

 be so large as to reach the pelvis and weigh many pounds. 



Its average length in ten adult men was found to be 12 cm. (five or six 



