434 



THE DIGESTIVE APPARATUS IN MAMMALIA. 



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 1^ and 4| inches. In the portion comprised between 

 the intestine and the origin of the cystic duct, it receives several biliary canals of some- 

 what considerable diameter. In the Cat, the ductus choledochus is most frequently 

 inserted from about 1 to lj inches from the pyloric orifice ; it opens immediately along- 

 side the pancreatic 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 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 

 duct opens with that of the liver. 



In the Pig, this duct is inserted 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 duodenum. It is curved at its anterior extremity, 

 behind the stomach, to one side of the median line. Its excretory duct, usually single, 

 pierces the intestinal membranes 2 inches beyond the hepatic duct (Fig. 219, ra). Except 

 in the mode of insertion of the excretory duct, which has been described in noticing the 

 ductus choledochus, the pancreas of the Cat comports 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 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 irregularly falci- 

 form, 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 AND THOSE OF ANIMALS. 



1. Liver. Like that of Euminants, the human liver is situated in the right excava- 

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

 oval, and its average weight from forty-nine to fifty-three 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 



220. ligament; it is smooth and con- 



vex. The inferior face has three 

 furrows, or fossae : two longitu- 

 dinal, united by a transverse, re- 

 sembling altogether the letter H. 

 The transverse furrow represents 

 that on the posterior aspect of 

 the liver of animals, and its des- 

 tination is the same. The right 

 long tudinal furrow lodges the 

 obliterated umbilical vein; the 

 left, well marked before and be- 

 hind, lodges the gall-bladder 

 in front, and the inferior vena 

 cava behind. This fttce 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. 



On the lower face of the right 



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, Poiis hepatis ; 8, Fossa of ductus venosus ; lobe are three depressions : an 

 9, Inferior vena cava; 10, Gall-bladder; 11, Trans- anterior or impressio colica ; a 

 verse fossa ; 12, Vena cava ; 13, Depression corres- deep middle one, impressio vesicee ; 

 ponding to the curve of the colon ; 14, Double and a small posterior one, which 

 depression produced by right kidney and supra-renal receives the supra-renal capsules, 

 capsule. impressio renalis. 



2. Pancreas. This organ is 



very elongated transversely, like that of the Dog and Cat. It is closely applied against 

 the lumbar vertebrae, as in the Horse, but its anterior face is much more enveloped by 

 the peritoneum Its right extremity rests on the duodenum, while the left corresponds to 



