OF THE INTESTINES AND THORAX. 493 



former originating in the subserous, and the latter in the submucous coat. They 

 follow the course of the bloodvessels, and may consequently be arranged into 

 three groups. The first group accompany the coronary vessels along the lesser 

 curvature, receiving branches from both surfaces of the organ, and pass to the 

 glands around the pylorus. The second group pass from the great end of the 

 stomach, accompany the vasa brevia, and enter the splenic lymphatic glands. 

 The third group run along the greater curvature with the right gastro-epiploic 

 vessels, and terminate at the root of the mesentery in one of the principal lacteal 

 vessels. 



The lymphatic glands of the spleen occupy the hilus. Its lymphatic vessels consist 

 of two sets, superficial and deep ; the former are placed beneath its peritoneal 

 covering, the latter in the substance of the organ : they accompany the blood- 

 vessels, passing through a series of small glands, and, after receiving the lymphatics 

 from the pancreas, ultimately pass into the thoracic duct. 



THE LYMPHATIC SYSTEM or THE INTESTINES. 



The lymphatic glands of the small intestine are placed between the layers of the 

 mesentery, occupying the meshes formed by the superior mesenteric vessels, 

 and hence called mesenteric glands. They vary in number from a hundred to a 

 hundred and fifty ; and in size, from that of a pea to that of a small almond. These 

 glands are most numerous, and largest, superiorly near the duodenum, and inferior ly 

 opposite the termination of the ileum in the colon. The latter group become 

 greatly enlarged and infiltrated with deposit in cases of fever accompanied with 

 ulceration of the intestines. 



The lymphatic glands of the large intestine are much less numerous than the 

 mesenteric glands ; they are situated along the vascular arches formed by the 

 arteries previous to their distribution, and even sometimes upon the intestine itself. 

 They are fewest in number along the transverse colon, where they form an unin- 

 terrupted chain with the mesenteric glands. 



The lymphatics of the small intestine are called lacteals, from the milk-white 

 fluid they usually contain ; they consist of two sets, superficial and deep ; the 

 former lie beneath the peritoneal coat, taking a longitudinal course along the 

 outer side of the intestine ; the latter occupy the submucous tissue, and course 

 transversely round the intestine, accompanied by the branches of the mesenteric 

 vessels: they pass between the layers of the mesentery, enter the mesenteric 

 glands, and finally unite to form two or three large trunks, which terminate in 

 the thoracic duct. 



The lymphatics of the large intestine consist of two sets : those of the caecum, 

 ascending and transverse colon, which, after passing through their proper glands, 

 enter the mesenteric glands ; and those of the descending colon and rectum, which 

 pass to the lumbar glands. 



THE LYMPHATICS OF THE THOEAX. 



The deep lymphatic glands of the thorax are the intercostal, internal mammary, 

 anterior mediastinal, and posterior mediastinal. 



The intercostal glands are small, irregular in number, and situated on each side 

 of the spine, near the costo-vertebral articulations, some being placed between the 

 two planes of intercostal muscles. 



The internal mammary glands are placed at the anterior extremity of each 

 intercostal space, by the side of the internal mammary vessels. 



The anterior mediastinal glands are placed in the loose areolar tissue of the 

 anterior mediastinum, some lying upon the Diaphragm in front of the pericardium., 

 and others round the great vessels at the base of the heart. 



The posterior mediastinal glands are situated in the areolar tissue in the posterior 

 mediastinum, forming a continuous chain by the side of the aorta and oesophagus ; 



