ORGANS ANNEXED TO THE ABDOMINAL DIGESTIVE CANAL. 433 



accumulates. When digestion commences again, this reserve of bile is thrown into the 

 ductus choledochus by the contraction of the muscular fibres of the cyst, and by the 

 pressure of the abdominal viscera ; it meets that which comes direclly from the liver, 

 and with it is carried to the duodenum. 



We will now glance at the particular arrangement of this viscus in each species. 



In the Ox, the liver is entirely confined to the right diaphragmatic region. It is 

 thick, voluminous, and scarcely notched at its periphery ; so that it is difficult, if not 

 impossible, to distinguish three lobes in it, the lobus Spigelii alone being detached from 

 the mass of the organ. The gall-bladder, fixed towards the superior extremity, is nearly 

 always floating ; near its neck it receives the insertion of several large conduits, which 

 come directly from the upper part of the liver. The ductus choledochus opens alone at 



Fig. 219. 



LIVER OF THE DOG, WITH ITS EXCRETORY APPARATUS. 



D, Duodenum and the intestinal mass ; P, Pancreas ; r, Spleen ; e, Stomach ; /, 

 Rectum ; R, Right kidney ; B, Gall-bladder ; ch, Cystic duct ; FF, Liver ; F', Lobe 

 of the liver, prepared to show the distribution of the vena porta and hepatic 

 vein ; VP, Vena portse ; vA, Hepatic vein ; d, Diaphragm ; vc, Vena cava 

 C, Heart. 



a great distance from the pylorus ; M. Colin has found it to be 24J inches in one cow, 

 and 29 inches in another. In the Sheep and Goat, the form and position of the liver 

 differs but little from that of the Ox. The ductus choledochus, however, unites with 

 that of the pancreas, and terminates at 12 to 16 inches from the pylorus. 



In the Pig, the liver has three well-marked lobes ; the middle carries the gall- 

 bladder. The ductus choledochus opens alone at 1 or 1^ inches only from the pylorus. 



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

 into five principal lobes. The middle lobe has 1he gall-bladder attached to it, and gives 

 it complete lodgment in a fossa. 



