THE LTVEK. 537 



special muscular coat. The gall-bladder has a layer of smooth mus- 

 cular fibres beneath its peritoneal covering. That of the ox may 

 be made to diminish its capacity one-fourth by a powerful galvanic 



Fig. 371. Fig. 372. 



Fig. 371. Narrowest portions of bile-duct, lined by its epithelium, continuous into the tubes con- 

 taining the hepatic cells. A venous capillary and a small branch of the artery are seen in section, 

 close to the narrow duct. The liver-cells have been destroyed by the reagents used in preparing 

 the specimen. (Human.) Magnified 215 diameters. (Dr. Beale.) 



Fig. 372. Terminal portion of interlobular duct, containing its epithelium, with four hepatic cells 

 to show the comparative size. 



battery. (Dr. Mayer.) Its mucous membrane presents many reticu- 

 lated, more or less prominent, folds, containing a capillary network 

 exactly like that of the foliaceous intestinal villi. It has also a 

 conoidal epithelium. Finally, the mucous membrane of the hepatic 

 ducts above T ^ of an inch in diameter contains a multitude of 

 small, racemose, yellowish mucous glands (KolliJcer) or sacculi (Dr. 

 Beale} ; while there are but few in the cystic duct, and usually none 

 at all in the gall-bladder. Dr. Beale finds these generally to be 

 simple oval pouches, arranged in two rows on opposite sides of the 

 duct, and connected with its cavity by a very narrow neck, often 

 not 50*00 of an mcn m diameter. In the larger ducts they are, 

 however, branched, and often run for some distance in the coats of 

 the duct. Occasionally the branches of one gland anastomose with 

 those of another. Fig. 373 shows the more simple, and Fig. 374 

 the complicated forms of these pouches in the pig; where they are 

 arranged completely around the duct. 



Many of the smaller ducts, about - of an inch in diameter, have 

 numerous caecal pouches, arranged pretty closely together, and 

 giving off branches of simple membrane only. These are very 

 numerous in the transverse fissure of the liver, where they form an 

 intricate network connected with the larger branches of the duct. 

 They were first noticed, and named vasa aberrantia, by Weber ; 

 and who also described the anastomosis between the right and left 



