198 CIRCULATORY SYSTEM. 



these spread their ramifications, in an arborescent form, upon the 

 upper and under surfaces of the stomach, and anastomose with 

 those of the right and left gastric. 



c. The hepatic artery, the largest of the coeliac divisions, pro- 

 ceeds in front of the pancreas to the right side of the cavity, and 

 winds forvrard over the pyloric end of the stomach. It gives off — 

 a. Divers small branches to the pancreas, as it passes by the 

 gland. /3. Near the pylorus, it sends a considerable branch to 

 the beginning of the duodenum, which, as soon as it reaches the 

 intestine, bifurcates: one division, the <fMoc?^//a/, retrogrades along 

 the gut, and ends in anastomosis with branches coming from the 

 anterior mesenteric; the other, the right gastric, crossing the gut, 

 proceeds to the great curvature of the stomach, where it inoscu- 

 lates with the left gastric. The hepatic trunk itself is continued 

 forward to the porta of the liver, where it divides into the right 

 and left hepatic: the right, the larger and shorter one, after giving 

 off a considerable branch to the portio media, turns back to reach 

 the right lobe ; the left also gives off a branch or two to the 

 middle portion, but they are but small, and then runs to the left, 

 along the left fissure, to penetrate the other lobe. 



2. The anterior or great mesenteric is the next 

 vessel to the coeliac, a little behind which it is issuing from the 

 under part of the posterior aorta. The trunk of this artery is ex- 

 tremely short; but it is of large size — aneurismal indeed in the 

 ass species — and is the parent stock of a numerous collection of 

 extensive ramifications. From its origin it passes directly down- 

 ward within the layers of the mesentery, detaching from behind 

 some slender twigs to the pancreas in its descent, and soon sud- 

 denly resolves itself into a set of branches, of very large size com- 

 pared with the trunk (commonly from eight to twelve in number), 

 varying in length and caliber, from which are derived — a. A 

 branch that runs to the duodenum, within the concavity of which 

 it divides into two small ones, which turn in opposite directions 

 and form arches ; one by union with the duodenal artery, the other 

 with the next mesenteric, from the convexities of which arise other 

 small transverse branches, which encircle the intestine and ramify 

 to great minuteness under its peritoneal covering, forming alto- 

 gether a beautiful vascular net-work. b. A collection of branches 

 of considerable length, more uniform than the rest, run backward 

 for the supply of the other small guts ; these in like manner run 

 in arches and inosculate, and furnish an abundant supply of 

 nutrient and secerning vessels, c. Two branches shorter than 

 the other proceed to the cxcum caput coli, whence they run 

 along the sides of the cacum, sending off numerous transverse 

 branches which encircle the gut and anastomose freely with each 



