When the internal structure of the pancreas is exa mined, it is found to be composed of irregular, glandu lar masses or lobes, connected by loose cellular sub stance, and giving to the peripheral surface rather an unequal appearance, except when the gland is distended, when it appears smooth and even. The whole substance of the gland is perforated longitudinally by an excretory duct of considerable size, of a whitish colour, but of thin and transparent coats, called the pancreatic duct. This duct is very small at its origin in the left extremity of the gland, hut becomes gradually larger as it ad vances to the right, receiving in its course numerous transverse branches from the lobes that compose the substance of the gland, till it finally perforates the side of the duodenum, running a little obliquely between the coats of that intestine, and opening into its cavity gene rally at the same place with the common biliary duct coming from the liver and gall-bladder.
The pancreas, like the salivary glands, is situated in the midst of organs that are much exposed to motion, by which the excretion of its secreted fluid is promoted; like them it is of a grayish colour and soft consistence, it is penetrated on all sides by numerous blood-vessels, and it secretes a fluid whit it is e xtremely similar to sa liva.
Few morbid appearances have hoer) observed in the pancreas. It has been u.ccrated, scir rhous, or containing calculous c oncretions. In all these affections it resembles the salivary glands. Li-,:tuatid relates a case in which the pancreas was altogether wanting.
The fluid secreted by the salivary glands is limpid, tasteless, and inodorous like water, but rathe• more vis cid than that fluid. Its specific gran its is rather greater, being about 1.09. It is usually frothy, and always as sumes this appearance when agitated. It does not rea dily mix with water; has a great affinity for oxygen, but readily imparts that principle to other bodies. li appears to contain mucilage, albumen, muriate of soda. and phosphates of soda, lime, and ammonia, all which constitute about one-lifth of its bulk, the remaining fuur-fifths being water.
The pancreatic juice has not been chemically exa mined. In its physical properties it resembles saliva, but appears to have rather a greater proportion of saline ingredients.
2. Of the The liver is the largest gland in the human body, and occupies a considerable portion of the cat ity of the bel ly. It is situated in the atlantal part of the cavity, im mediately below the diaphragm, tilling up the whole of the right hypochondrium, and reaching across the epi gastric region into the left which it partly occupies. (See Plate MX. Fig. 9. L, L.) It is of a very irregular figure, convex on that surface which is next the diaphragm, concave on the opposite surface; very thick towards the right side, but becoming gra dually thinner towards the left ; has a thick round edge next the vertebrx,and on the right side, but terminates in an acute edge in its sternal part. It does nut lie in a
horizontal position, but its thick dorsal margin is con siderably more atlantal than its sharp sternal edge. It is divided by a fissure near the middle of its concave surface into two large unequal portions called its great lobes. Of these, that towards the right is larger than the other. There is also a smaller lobe than either of these, situated at its atlantal and dorsal part, called the lobe of Spigelius. The liver is inveloped in a peripheral coat, derived from the peritoneum that lines the cavity of the belly, and it is attached to the neighbouring- parts by doublings of the same membrane, which, Irom their office, arc called the /ig-wilen 's of the liver. Of these ligaments the most remarkable is that which extends from the fissure between the two great lobes to the dia phragm, and is called the or -cuviensGrij //gam -a% The convex surface of the right lobe is attached to the diaphragm by a production called the cormary ligament, and two other productions of the peritoneum, by which the sides of the liver are attached to the neighbouring viscera, are called the lateral ligaments ; and besides the-se there is a cord that extends from a doubling in the sacral part of the broad ligann ut to the navel, called the round ligament, Which we shall presently more par ticularly notice. The left lobe of the l iva r lies over the pyloric portion of the stomach, and is attached to the left side of the colon, while the right lobe is attached by the right lateral ligament to the right flexure of that intestine. The pancreas lies just stet sad of the great fissure.
The concave surface of the liver is very irregular, having se ;eral remarkable pi ominences and depressions. A little sternal and sorrel 01 the lobe ol Spigelius, there is a protuberance broader than that lobe, but less prominent, to which anatomists have given the absurd name ol lobules ammymnd, and from this lobule there frequently runs all arch over the passage for the round ligament to the left lobe, which is ca,lcd the bridge or isthmus of the liver. That part of the great fissure which is bounded on the right and left by the two great lobes, dorsad by the lobe of Spigehius, and sternal by the anonymous lobule. is called the transverse fissure, porta or .sinus and these two small lobes are called the porta. or gates. depression is pa•ticu larly deserving of notice, as it is that part by which the trunks of the great blood-vessels that supply the liver enter, and front which its excretory ducts pass out.