688 ORGANS OF DIGESTION. 



albuminous. These bodies are very large after digestion is completed, in well-fed 

 animals, and especially in those fed upon albuminous diet. In starved animals, 

 they disappear altogether. 



The splenic artery is remarkable for its large size, in proportion to the size 

 of the organ ; and also for its tortuous course. It divides into from four to six 

 branches, which enter the hilus of the organ, and ramify throughout its substance 

 (fig. 350), receiving sheaths from an involution of the external fibrous tunic, 

 the same sheaths also investing the nerves and veins. Each branch runs in the 

 transverse axis of the organ, from within outwards, diminishing in size during its 

 transit, and giving off, in its passage, smaller branches, some of which pass to the 

 anterior, others to the posterior part ; these ultimately terminate in the proper 

 substance of the spleen, in small tufts or pencils of capillary vessels, which lie in 

 direct contact with the pulp, teach of the larger branches of the arteries supplies 

 chiefly that region of the organ in which the branch ramifies, having no anasto- 

 mosis with the majority of the other branches. 



The capillaries, supported by the minute trabeculas, traverse the pulp in all 

 directions, and terminate either directly in the veins, or open into lacunar spaces, 

 from which the veins originate. 



The veins are of large size, as compared with the size of the organ, and their 

 distribution is limited, like that of the arteries, to the supply of a particular part 

 of the gland ; they are much larger and more numerous than the arteries. They 

 originate, 1st, as continuations of the capillaries of the arteries ; 2dly, by inter- 

 cellular spaces communicating with each other ; 3dly, by distinct cascal pouches. 

 By their junction they form from four to six branches, which emerge from the 

 hilus ; and these, uniting, form the splenic vein, the largest branch of the vena 

 portos. 



The lymphatics form a deep and superficial set ; they pass through the lym- 

 phatic glands at the hilus, and terminate in the thoracic duct. 



The nerves are derived from branches of the right and left semilunar ganglia, 

 and right pneumogastric nerve. 



