PANCREAS. 



81 



PANCREAS (n&yKpeas*, Gr. ; Pancreas, 

 Lat. ; /6> Pancreas, Fr. ; die Bauchspeicheldruse, 

 Germ. ; Pancrea, Ital.). The pancreas is an 

 azygous, non-symmetrical, glandular organ, 

 possessing a duct, and, therefore, belonging 

 to the category of true glands; connected 

 anatomically with the alimentary canal, and 

 physiologically with the function of digestion. 



On taking even the most superficial and 

 general view of this organ, two or three things 

 cannot fail to strike the attention : one is, the 

 close affinity and strong contrariety which it 

 at the same time displays to the salivary 

 glands f affinity in point of appearance and 

 structure, being, like them, a typical represen- 

 tation of a conglomerate gland, contrariety 

 in point of situation and function, the one 

 being placed at the very threshold of the ali- 

 mentary canal, the other at an advanced po- 

 sition in it ; the one acting on raw material, 

 and having in part at least a mechanical use J, 

 the other having to do with material far gone 

 in the process of assimilation, and possessing 

 a function, whatever it may be, certainly not 

 mechanical in any degree. 



Another striking circumstance is its wide 

 diffusion. It exists in all vertebrata ; mam- 

 malia, birds, reptiles, and most fishes, all 

 possess a pancreas, and that quite independent 

 of what the nature of their food may be, 

 animal, vegetable, or mixed ; a fact that one 

 would have imagined would itself have pre- 

 vented the adoption of the old views with 

 regard to its function. 



Another circumstance, not less striking, 

 is its constant relation to the duodenum : 

 whatever may be the other modifications of 

 the alimentary canal, from the straight and 

 simple tube of some carnivora to the volu- 

 minous apparatus of the vegetable feeders, 

 or whatever may be the modified form of the 

 pancreas itself, still, if the organ exists, its 

 relation to the duodenum is invariable ; if 

 there is a duodenal fold, it is placed in it ; and 

 if there is not, it makes the closest approxi- 

 mation to an analogous position that is pos- 

 sible : indeed the uniformity of this relation 

 is so invariable, even under circumstances 

 where it would appear to be indifferent, that 

 one cannot but regard it as one of those in- 

 stances of conformity to type in which uni- 

 formity appears to exist for uniformity's sake. 



The arrangement of the subject of this 

 paper that most naturally suggests itself, is 

 to treat first of the structure, and then of the 

 functions of the organ. I shall therefore 

 arrange my observations under the following 

 heads : 



1st. The descriptive anatomy of the human 

 pancreas, including an account of so much of 

 its structure as may be made out by a naked- 

 eye examination. 



2nd. Its minute or general anatomy. 



f, all flesh. 



This striking resemblance suggested to the 

 older anatomists the name of "salivary gland of 

 the abdomen," an appellation first given to it by 

 Siebold. Historia Systematis Salivalis. 



J See Bernard's experiments on the secretion of 

 saliva. 

 Supp. 



3rd. Its comparative anatomy, including 

 those modifications both of the form and ulti- 

 mate structure of the gland that the animal 

 series exhibits. 



4-th. The physiology of the pancreas, the 

 role that it plays in the function of digestion. 



Lastly. A short account of some of the most 

 striking pathological changes that the organ 

 is liable to. 



I. HUMAN ANATOMY. 



Situation. The pancreas is so placed that 

 for its display it is necessary to open the ca- 

 vity of the great omentum. This may be done 

 either by dividing the gastro-hepatic omentum 

 and depressing the stomach, or by detaching 

 the gastric layer of the epiploon and turning 

 the stomach up, or by dividing the transverse 

 mesocolon and turning up both transverse 

 colon and stomach. In either of these ways 

 the cavity of the omentum is opened, and the 

 organs concealing the pancreas are removed. 



Placed transversely across the upper part 

 of the abdominal cavity, and closely applied 

 to its posterior wall, the pancreas extends from 

 the duodenal fold on the right to the hilum 

 of the spleen on the left, across, therefore, the 

 epigastric into both hypochondriac regions. It 

 is not perfectly transverse, however, but ex- 

 tends from the right a little upwards as well 

 as to the left; it corresponds to the level of 

 the first and second lumbar vertebrae and to 

 the splitting of the two laminae of the trans- 

 verse mesocolon : it is post-peritoneal, being 

 invested by that membrane only on its an- 

 terior surface. 



Relations, By its right extremity it is 

 closely engaged in the curvature of the duo- 

 denum, to the inner border of which it is 

 intimately attached, and which it often re- 

 ceives into a groove more or less deep, formed 

 by a projection of the gland to a slight extent 

 on the anterior and posterior surface of the 

 intestine. Sometimes this groove is very 

 slight, and the relation of the margins of the 

 gland and intestine merely that of apposi- 

 tion ; at others, the inner margin of the duo- 

 denal fold will be deeply imbedded in the 

 gland substance, the projection both in front 

 and behind being considerable. More fre- 

 quently, however, the gland trespasses much 

 further behind the intestine than it does in 

 front, so much so occasionally as to separate 

 it in a great degree from its posterior rela- 

 tions. The structures on which the posterior 

 surface of the pancreas rests are, the vena 

 cava, the bodies of the vertebrae, the aorta, 

 the crura of the diaphragm, the left kidney, 

 its supra-renal capsule and renal vessels, the 

 lower part of the solar plexus with the com- 

 mencement of the plexuses thence pro- 

 ceeding, as the aortic and superior mesenteric ; 

 the splenic vein passing from left to right, 

 the superior mesenteric vein and artery, the 

 vena porlae, the common bile duct, many lym- 

 phatic vessels and glands, and the commence- 

 ment of the thoracic duct and vena azygos. 

 To all these structures it is intimately at- 

 tached by cellular tissue, and to the irregular 

 surface which they form it is, as it were, 

 moulded or modelled, so that when it is care- 



G 



