510 



THE DIGESTIVE APPARATUS IN MAMMALIA. 



In the Dog and Cat, the liver is very voluminous, 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 choledochus, joined to a small branch from the pancreatic duct, 

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

 animal, but usually between IJ and 4f incht s. In the portion comprised between the intestine 

 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 IJ 

 inches from the pyloric orifice; it opens immediately alongside the pancreatic duct, when it 

 does not join it. ■ u • 



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

 comprised between th.- layers of the mesentery, to the right of the great 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 the same general arrangement, but the excretory ducts 

 opens with that of 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 fiexure of the colon ; the other portion is lodged 



in the duodenal fraenum. The duct of 



Fig. 304. 



UNDER SURFACE OF THE HUMAN LIVER. 



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

 lobus Spigelii; 5, lobus caudatus ; 6, longitudinal 

 fossa ; 7, pons hepatis ; 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 inserteil at from 4 to 6 inches 

 behind the ductus choledochus. 



The pancreas of the Dog is extremely 

 elongated, and included between the layers 

 of the mesentery which sustain the duo- 

 denum. It is curved at its anterior ex- 

 tremity, beliind the stomach, to one side 

 of tlie median line. Its excretory duct — 

 usually single — pierces the intestinal mem- 

 branes 2 inches beyond the hepatic duct 

 (Fig. 290, m). Except in the mode of 

 insertion of the excretory duct, which 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, the spleen 

 is not supported by the great omentum, but 

 adheres to the left side of the rumen and 

 diaphragm. It is not falciform, and its 

 breadth is the same througliout its extent. 

 In the Camivora, 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 of the Abdominal Portion of the 

 Digestive Canal in Man with those of Animals. 



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

 of the lower face of the diaphragm. Its direction is nearly horizontal ; its shape is oval, 

 and its average weight from 49 to 53 ounces. The posterior border is thick and round; 

 the anterior border and extremities thin and sharp. The upper face, which in i-xpiration 

 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 longi- 

 tudinal, united by a transverse, resembling altogether tlie letter H. The traiisverse furrow 

 represents that on the posterior aspect of the liver of animals, and its destination is the same. 

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

 before and behind, lodges the gall-bladder in front, and the inferior vena cava behind. This 

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

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



