THE GALL-BLADDER. 537 



the blood now becomes venous, is believed to be returned into the 

 smaller portal veins, and in this indirect manner only, to reach the 

 hepatic lobules. According to this view, amongst the sources of the 

 portal blood, must be included, not only the stomach, intestinal canal, 

 pancreas, gall-bladder, and spleen, but also the non-secreting part of 

 the liver itself. 



The secreting portion of the liver is composed, in each lobule, first of 

 the lobular capillary network or venous plexus, already mentioned, as in- 

 terposed between the termination of the portal and the commencement 

 of the hepatic venous systems; secondly, of an intermediate gland- 

 substance or parenchyma, occupying the interstices of this capillary 

 network ; and thirdly, of the commencements of the hepatic or biliary 

 ducts. The gland-substance consists of roundish, or flattened, poly- 

 hedral, nucleated cells, having a delicate cell-wall, one or two bright 

 vesicular nuclei with riucleoli, and certain faintly yellowish, semifluid, 

 amorphous, granular contents, in which are commonly found larger or 

 smaller globules of oily matter. These very peculiar cells are named 

 the hepatic cells ; they vary from y^^th to gjoth of an inch in di- 

 ameter. They are the true secreting gland-cells of the liver, their 

 contents closely resembling the bile, which is secreted by them. The 

 relation of these cells to the finest commencements of the biliary 

 ducts, and the mode of commencement of those ducts, are difficult 

 points for investigation. The clusters of the hepatic cells occupy the 

 interstices of the lobular venous plexus, and, whatever may be their 

 relation to the finest commencements of the ducts, or in whatever 

 mode the bile, formed within these cells, passes into the ducts, the 

 hepatic cells themselves lie outside the venous plexus, and this has no 

 direct communication with the ducts. The hepatic cells, moreover, 

 are arranged in lines or rows, which radiate, amongst the bloodvessels, 

 from the centre towards the circumference of the lobule. By most 

 anatomists, these rows of cells are said to be supported on a thin 

 basement-membrane, which is continuous with the walls of the com- 

 mencing efferent biliary tubes or ducts, so that the liver might be 

 regarded as a complex gland, having ramified anastomosing ducts 

 (Beale and Retzius). According to another view, however, the hepatic 

 cells are merely arranged around the network of the lobular plexus, 

 and are unsupported by a proper basement-membrane (Kolliker). 



The G-all-bladder. The hepatic, cystic, and common bile ducts, 

 already described, are composed of a strong areolar coat, containing 

 a few muscular fibres, and lined by a mucous membrane covered with 

 a columnar epithelium ; in the finest ducts, the epithelium is squamous. 

 The walls of these ducts present generally minute racemose mucous 

 glands, the openings of which are arranged in rows within the ducts. 

 The cystic duct which leads to the gall-bladder has, in its interior, a 

 series of oblique crescentic projecting ridges or folds, following each 

 other closely, so as to present the appearance of a spiral valve. 



The gall-bladder, Fig. 96, g, is a pear-shaped sac, from 3 to 4 inches 

 long, about 1 inch across at its widest part, and holding rather more 

 than one fluid ounce. It is lodged in a fossa on the under surface of the 

 liver ; its larger end or fundus, projects beneath the anterior border 



