LYMPHATIC AND LACTEAL SYSTEM. 



229 



the chyle is supposed to enter by imbibition. 

 This incipient net-work of lacteals terminates at 

 the roots of the villi in branches, which perforate 

 the muscular coats of the intestines, the trunks 

 of which may be easily distinguished under 

 the serous coat, taking a transverse course to 

 gain the cellular interval between the layers of 

 the mesentery. These are what may be termed 

 the deep-seated lymphatics of the intestines 

 which alone contain the chyle, but there are 

 superficial lymphatics belonging to the intes- 

 tines situated immediately under the peritoneal 

 coat, which take a longitudinal course and 

 join the deep-seated vessels. From the intes- 

 tine the principal branches pass in nearly 

 straight lines between the layers of the mesen- 

 tery, where they traverse the mesenteric glands 

 to accumulate from every portion of the small 

 intestine around the trunk of the superior 

 mesenteric artery. The lymphatics from the 

 ccecum, the ascending and transverse colon, 

 which have passed through their appropriate 

 glands and have accompanied more or less the 

 ilio-colic and colic arteries between the layers 

 of the meso-colon, now join the lacteal vessels. 

 The vasa efferentia from the mesenteric glands 

 form two or more trunks, which, conducted 

 by the root of the superior mesenteric artery, 

 reach the thoracic duct, into which they empty 

 their contents just above its commencement. 



The lymphatics of the stomach chiefly 

 accompany the bloodvessels. Those associated 

 with the vasa brevia and with the left gastro- 

 epiploic vessels, having passed through their 

 glands unite with the lymphatics from the 

 spleen. Those accompanying the right gastro- 

 epiploic vessels having traversed their glands 

 communicate behind the pyloric extremity of 

 the stomach and at the commencement of the 

 duodenum, with the lacteals, and with the 

 lymphatics from the liver. At the upper cur- 

 vature of the stomach, the lymphatics take their 

 course from the cardiac to the pyloric orifice 

 accompanying the branches of the coronaria 

 ventriculi arteries, they pass through the glands 

 there situated, and join the lymphatics descend- 

 ing from the liver in the capsule of Glisson. 



The lymphatics of the pancreas near the 

 head of the organ communicate with the lacteal 

 vessels from the duodenum ; the rest empty 

 themselves into the lymphatics coming from 

 the spleen. 



At the hilum of the spleen the deep-seated 

 lymphatics which have accompanied the blood- 

 vessels in the substance of the organ are joined 

 by the superficial vessels. The principal 

 branches having in their course received lym- 

 phatics from the stomach and pancreas, and 

 having traversed the splenic glands, accompany 

 the trunks of the splenic artery and vein, and 

 unite with the lymphatics of the liver in their 

 course to the thoracic duct. 



The deep-seated lymphatics of the liver 

 accompany the ramifications of the portal 

 vessels throughout the 'substance of the organ ; 

 they emerge with the hepatic ducts at the 

 transverse fissure of the liver, where they are 

 joined by the lymphatics of the gall-bladder 

 and by the superficial lymphatics from the 



under surface of the liver. They pass through 

 the glands situated in the capsule of Glisson, 

 receive free communications from the splenic 

 and gastric lymphatics, and ultimately termi- 

 nate in the thoracic duct either separately or 

 in conjunction with the lacteal trunks. 



The superficial lymphatics of the upper 

 surface of the liver form three or four fasciculi, 

 which enter the thorax without joining the 

 trunks of the deep-seated vessels. One set 

 streams from the upper surface of the right, 

 another from that of the left lobe to gain the 

 suspensory ligament of the liver, between the 

 folds of which the larger branches, six or eight 

 in number, pass upwards and enter the thorax 

 between the attachment of the diaphragm and 

 the ensiform cartilage to gain the anterior 

 mediastinum, where they join the large lym- 

 phatic vessels accompanying the arteriee mam- 

 marioe internee. From the right and left lobes 

 in the neighbourhood of the lateral ligaments, 

 and chiefly, though not entirely, from the 

 upper surface of the organ, two other streams 

 of superficial lymphatics tend towards the 

 lateral ligaments, between the layers of which 

 the principal branches pass. They perforate 

 the diaphragm to gain its upper surface, some 

 of them passing backwards to reach the thoracic 

 duct in the posterior mediastinum, while others 

 form a large vessel which creeps upon the 

 thoracic surface of the diaphragm under the 

 pleura and near the margin of the ribs, to gain 

 the anterior mediastinum, where on each side 

 it unites and terminates with those vessels 

 which have arrived at the same point from 

 between the folds of the suspensory ligament. 

 The lymphatics of the left lateral ligament 

 often, however, pass downwards to the abdo- 

 minal cavity, joining the lymphatics of the 

 under surface of the liver or of the cardiac 

 extremity of the stomach. 



The thoracic duct receives but four branches 

 during its passage through the thorax ; the 

 lymphatics of the lungs and of the heart, as well 

 as the large branches accompanying the mamma- 

 rise internee vessels, make their exit from the 

 thoracic cavity, to empty themselves into the 

 two lymphatic trunks in the cervical region. The 

 intercostal lymphatics accompanying the inter- 

 costal bloodvessels, traverse the little glands si- 

 tuated near the necks of the ribs, take their 

 course to and enter the larger glands in the pos- 

 terior mediastinum. These same glands also 

 receive the cesophageal lymphatics, and even 

 some communications from the bronchial 

 glands ; their vasa efferentia, four or five in 

 number, enter the thoracic duct at different 

 levels. 



The large lymphatics accompany ing the mam- 

 marise internee arteries collect their branches 

 from various sources; those from the liver have 

 been already noticed ; some pass through the in- 

 tercostal spaces close to the edges of the ster- 

 num : some have accompanied the intercostal 

 branches of the mammarise internse vessels; 

 others are received from the thymus gland and 

 pericardium and pleura. The greater part of 

 these vessels pass through the little glands si- 

 tuated in the anterior mediastinum before they 



