246 EXCRETION. 



the interlobular ducts. We shall see, further on, that the 

 ducts, in their course from the lobules to the intestine, are 

 provided with numerous small racemose glands, which prob- 

 ably secrete a mucus that is mixed with the bile ; but, in all 

 probability, the peculiar elements of the bile are formed in 

 the lobules, and the canals situated between the lobules and 

 leading from them to the larger ducts are merely excre- 

 tory. 



Between the lobules the ducts are very small, the smallest 

 measuring about -^-gVo" f an ^ ncn m diameter. They are 

 composed of a delicate membrane, lined with small, flat- 

 tened epithelium. According to Robin, the cells lining the 

 excretory ducts are ciliated ; l but this is not the view gener- 

 ally adopted. The ducts larger than 12 1 00 of an inch have 

 a fibrous coat, formed of inelastic, with a few elastic ele- 

 ments, and in the larger ducts there are, in addition, a few 

 non-striated muscular fibres. The epithelium lining these 

 ducts is of the columnar variety, the cells gradually under- 

 going a transition from the pavement form as the ducts in- 

 crease in size. In the largest ducts there is a distinct mu- 

 cous membrane, with mucous glands. 



Throughout the whole extent of the biliary passages, 

 from the interlobular canals to the ductus choledochus, are 

 little utricular or racemose glands, varying in size in differ- 

 ent portions of the liver, called, by Robin, the biliary acini. 

 These are situated, at short intervals, by the sides of the 

 canals. The glands connected with the smallest ducts are 

 simple follicles, from -g-J-g- to ^-J-g- of an inch long. The 

 larger glands are formed of groups of these follicles, and 

 measure from -g-J-^ to y^- of an inch in diameter. The glands 

 are only found connected with the ducts ramifying in the 

 substance of the liver, and do not exist in the hepatic, cystic, 

 and common ducts. They are composed of a homogeneous 

 membrane, lined with small, pale cells of pavement-epithe- 



1 LITTRE ET ROBIN, Dictionnaire de medecine, Paris, 1865, p. 611, Article, 

 Foie. 



