BLOOD-VESSELS NERVES LACTEALS. . 109 



in man, for the most part, a pretty large deposit of fat. The 

 ox has likewise around the great intestines the epiploic ap- 

 pendages of the same character as those known in man. 



Blood -Vessels. The arteries which supply the intestines 

 with blood are branches of the posterior aorta namely, the 

 anterior and posterior mesenteric arteries. The posterior mes- 

 enteric artery is small in the ox, owing to the close connection 

 between the small and the great intestines, so that the anterior 

 mesenteric greatly preponderates in size. The branches of the 

 anterior mesenteric which supply the intestines are : first, three 

 considerable branches which give blood to the commencement 

 of the small intestine ; then a large branch directed to the colon 

 and caecum ; then a last branch, which furnishes branches to 

 the small intestines as these pass backwards to the remotest 

 part of the mesentery. These branches do not form arches, 

 as in man, nor do they anastomose frequently with each other, 

 but proceed straight to the intestines. The small posterior 

 mesenteric in the ox carries blood principally to the rectum, 

 the few twigs sent to the colon being altogether unimportant. 



The veins of the intestines enter into the formation of the 

 portal vein. 



Nerves. The nerves of the intestines are derived from the 

 anterior mesenteric plexus, the posterior mesenteric plexus, and 

 the hypogastric plexus, all which are formed by the splanchnic 

 nerves of the sympathetic system. Like the blood-vessels, the 

 nerves reach the intestines by passing between the folds of the 

 mesentery. 



Lacteals. Between the laminae of the mesentery also are 

 lodged the lacteal and lymphatic vessels, and the glands con-' 

 nected with these, which bear so important a part in the 

 function of nutrition. 



The principal trunk of the absorbent system, termed the 

 thoracic duct, is traced running forward along the spine to 



