286 PRACTICAL HISTOLOGY. [XXVI. 



but always separated from the blood-capillaries by hepatic cells or 

 part of a cell, is a fine polygonal plexus of channels the bile 

 capillaries, which become continuous with interlobular bile-ducts 

 at the margin of the lobule. The smaller interlobular bile-ducts 

 unite to form larger bile-ducts, which are lined by columnar epi- 

 thelium, and in the walls of the largest of them are mucous glands. 

 The hepatic artery supplies chiefly the connective tissue between 

 the lobules, and accompanies the branches of the bile-duct and 

 portal veins, so that these three structures lie together in portal 

 canals. 



Methods. Harden portions of the liver of a, e.g., pig, rabbit, cat, 

 and man in Miiller's fluid or 2 per cent, potassic bichromate (10-14 

 days). If it be desired to retain the chromatin fibrils in the liver- 

 cells avoid the chromic acid salts. Use sublimate, and then 

 gradually increasing strengths of alcohol. Cut sections parallel to the 

 surface of the organ, and others at right angles to it, the latter to 

 include the capsule. The sections can be stained in haematoxylin 

 and mounted in balsam ; or picro-carmine, or picro-lithium carmine, 



and Farrant's solution 

 may be used. Staining 

 in bulk and cutting in 

 paraffin is also good. 



If unstained sections 

 are mounted, the out- 

 lines of the tissues will 

 be much better defined 

 if they be soaked in i 

 per cent, osmic acid (24 

 hours) previous to being 

 mounted in Farrant's 

 solution. 



1. Liver of Pig 

 275. Liver of Pig, showing Lobules. P.O. Portal (Hcematoxylin and .Ba/- 



canal, containing Me-duct, hepatic artery, and por- sam or PicrolitUum 

 tal vein (P. V.) S. Septa ; S. V. Sublobular vein ; /. V . . 



intraiobuiar vein. Carmine, or Methylene- 



Blue). 



(a.) (L) Observe the polygonal lobules (fig. 275) mapped out from 

 each other by a network of septa of connective tissue, or Glisson's 

 capsule (fig. 275, S). In the centre of each lobule a small thin- 

 walled vein, a rootlet of the intraiobuiar or hepatic vein 

 (I.V.). 



(b.) At the periphery of each lobule sections of branches of the 

 portal or interlobular vein ; if possible, find a transverse section of 

 the latter, and it will be found to be accompanied by similar sec- 

 tions of the bile-duct (one or more) and hepatic artery (fig. 277, 



