510 



THE DIGESTIVE APPARATUS IN MAMMALIA. 



In the Dog and Cat, the liver is very vohiminous, is deeply notched, and is divided into 

 five principal lobes. The middle lobe has the gall-bladder attached to it, and gives it complete 

 lodgment in a fossa. 



In the Dog, the ductus cho I edochus, joined to a small branch from the pancreatic duct, 

 enters the iulestiue at a variable distance from the pylorus, depending upon the size of the 

 animal, but usually between IJ and 4f inches. In the portion comprised between the intes ine 

 and the origin of the cystic duct, it receives several biliary canals of somewhat considerable 

 diameter. In the Cat, the ductus choledochus is most frequently inserted from about 1 to 1^ 

 inches from the pyloric orifice; it opens immediateiy alongside the paucreaiic duct, when it 

 does not join it. 



2. Pancreas.— In the Ox, the pancreas is not placed across the sublumbar parietes, but is 

 comprised between the lay* rs of the mesentery, to the right of the gieat mesenteric artery. 

 The excretory duct is single, and opens into the small intestine at from 14 to 16 inches beyond 

 the ductus choledochus. 



In the Sheep and Goat, there is tlie same general arrangement, but the excretory ducts 

 opens with that ot the liver. 



In the Pig, a portion of the pancreas is situated in the sublumbar region, between the 

 large tuberosity of the stomach and the last flexure of tlie colon ; the otiier portion is lodged 



in the duodenal frjenum. The du- 1 of 



Fig. 304. 



...ffilfSpP 



UNDER SURFACE OF THE HUMAN LIVER. 



1, Right lobe; 2, left lobe; 3, lobus quadratus ; 4, 

 lobus Spigelii ; 5, lobus caudatus ; 6, loruiitudinal 

 fossa ; 7, pons hepatic ; 8. fossa of ductus venosus ; 

 9, inferior vena cava; 10. gall-bladder; 11, trans- 

 verse fossa; 12, vena cava; 13, depression corre- 

 sponding to the curve of the colon; 14, double 

 depression produced by right kidney and supra- 

 renal capsule. 



Wirsung is inserted at from 4 to 6 i' jhes 

 behind the ductus cho'.edoclius. 



The pancreas of tiie Dog is extr nely 

 elongated, and included betwueii the j,yer3 

 of the mesentery which sustain th' duo- 

 denum. It is curved at its anter r ex- 

 tremity, behind the stomach, to oi • side 

 of tile median line. Its excretory uct — 

 usually single — pierces the intestins mem- 

 branes 2 inches beyond the hepa^ c duct 

 (Fig. 290, m). Except in the i .ode of 

 insertion of the excretory duct, wl ich has 

 been described in noticing the ductus 

 choledochus, the pancreas of the Cat com- 

 ports itself exactly like that of the Dog. 



3. Spleen. — In Ruminants, tiiespleen 

 is not supported by the gieat omentum, but 

 adheres to the left side of the rumt-n and 

 diaphragm. It is not falciform, and its 

 breadth is the same throughout its extent. 

 In the Carnivora, it is suspended to the 

 great omentum at a certain distance from 

 the left sac of the stomach. It is irregu- 

 larly falciform, its point is less acute than 

 in Solipeds, and is directed upwards. 



Comparison between the Annexed Organs op the Abdominal Portion of the 

 Digestive Canal in Man with those of Animals. 



1. Liver. — Like that of Ruminants, the liver of Man is situated in the right excavation 

 of the lower face of the diaphragm. Its direction is nearly iiorizontal ; its «hape is oval, 

 and its average weight from 4l> to 53 ounces. The posterior border is thick and round; 

 the anterior border and extremities thin and sharp. The upper face, which in expiration 

 ascends to the fourth rib, is divided into two portions or lobes — right .and left, by the falciform 

 ligament : it is smooth and convex. The inferior face has three furrows, or fossae : two lonjji- 

 tudinal, unite I by a transverse, resembling altogether the letter H. The transverse furrow 

 represents that on the posterior nspect of the livt'r of animuls, and its destination is the same. 

 The right longitudinal furrow hidges the obliterated umbilical vein ; tlie left, well marked 

 before and behind, lodges the gall-bladilcr in front, and the inferior vena cava behind. Tins 

 ftice has four lobes, the right nnd left, and two middle lobes. In front of the transverse furrow 

 is the lobus quadratus, and behind the same fissure is the lobus Spigelii. 



