XERVE3 AND LYMPHATICS OF THE LIVER. 249 



animals there is a distinct muscular coat, but a few scattered 

 fibres only are found in the human subject. The mucous 

 coat is of a yellowish color, and marked with numerous 

 very small, interlacing folds, which are exceedingly vascular. 

 Like the membrane of the ducts, the mucous lining of the 

 gall-bladder is covered with columnar epithelium. In the 

 gall-bladder are found numerous small racemose glands, 

 formed of from four to eight follicles lodged in the submu- 

 cous structure. These are essentially the same as the glands 

 opening into the ducts in the substance of the liver, and 

 secrete a mucus, which is mixed with the bile. 



Nerves and Lymphatics of the Liver. The nerves of the 

 liver are derived from the pneumogastric, the phrenic, and 

 the solar plexus of the sympathetic. The branches of the 

 left pneumogastric penetrate with the portal vein, while the 

 branches from the right pneumogastric, the phrenic, and the 

 sympathetic surround the hepatic artery and the hepatic duct. 

 All of these nerves penetrate at the transverse fissure and 

 follow the blood-vessels in their distribution. They have 

 not been traced farther than the terminal ramifications of 

 the capsule of Glisson, and their exact mode of termination 

 is unknown. 



The lymphatics of the liver are very numerous. They 

 are divided into two layers : the superficial layer, situated 

 just beneath the serous membrane; and the deep layer, 

 formed of a plexus surrounding the lobules and situated 

 outside of the blood-vessels. The superficial lymphatics 

 from the under surface of the liver, and that portion of 

 the deep lymphatics which follows the hepatic veins out 

 of the liver, pass through the diaphragm and are con- 

 nected with the thoracic glands. Some of the lymphatics 

 from the superior or convex surface join the deep vessels 

 that emerge at the transverse fissure, and pass into glands 

 below the diaphragm, while others pass into the thoracic 

 cavity. 



