408 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



around the walls of the vein leaving but little room for other struc- 

 tures than the gall-ducts and hepatic arteries. In the finer interlo- 

 bular septa picrocarmine reveals very little connective tissue. 



The arrangement of the blood vessels in the liver is, on the whole, 

 the same as in the higher vertebrates. There are, however, minor 

 differences. The interlobular veinlets, before they pass into the 

 radial capillaries, are closely gathered together to form as it were a 

 wall to separate two neighbouring lobules which are thereby sharply 

 defined. The course of the radial capillaries from the central vein 

 outwards is very irregular. The spaces enclosed by two adjacent 

 radials and their transverse branches, instead of being uniformly 

 'quadrilateral as in higher vertebrates, are more or less rounded. 



The different gall-ducts are lined with an outer fibrous and an 

 inner epithelial coat. The fibrous layer is formed of connective tis- 

 sue fibrils and plain muscle fibres, the latter situated inside the for- 

 mer, which passes into the differently arranged scanty connective 

 tissue surrounding the duct. Staining with picrocarmine easily 

 reveals this arrangement. The inner or lining coat of epithelium 

 consists of a single layer of short cylinder cells. They are slightly 

 granular, and their nuclei are placed near the bases of the respective 

 cells. A peripheral wall is present. As the ducts become more 

 finelv branched these cells become columnar, then oval ; at the same 

 time the fibrous layer loses its connective fibrils, those of the muscu- 

 lar coat becoming much decreased in quantity and finally vanishing. 

 When the connective tissue is absent but the muscular fibrils still 

 present, the epithelium becomes scale-like, forming, when the muscle 

 fibres vanish, a thin wall for the lumen of the gall capillary. I 

 have not succeeded in following them to their terminations in the 

 hepatic cylinders, but believe that they terminate, as Hering and 

 others describe, by their epithelium becoming exchanged for liver- 

 cells, which here, however, do not possess a thickened border disposed 

 toward the lumen of the gall capillary. 



As already stated, very little if any connective tissue enters be- 

 tween the lobules, and thence the sole supporting stroma is formed by 

 the blood capillaries. There is a complete absence of those cells, other 

 than hepatic, which sometimes characterize the livers of higher ver- 

 tebrates. Kupffer's stellate cells, which are rendered remarkably 

 distinct in other livers by methylene blue, cannot be detected here. 



