288 PRACTICAL HISTOLOGY. [XXVI. 



2. Liver of Rabbit. It is convenient to study this liver, because 

 in some respects it shows a transition between that of the pig and 

 man, as it occupies an intermediate place with regard to the demar- 

 cation of its lobules. In it the lobules are not nearly so well 

 defined by connective tissue as in the pig or camel, while their 

 separation from each other is more definite than in man. 



3. Human Liver. Hsematoxylin, balsam. 



(L) Observe the greater fusion of the lobules. Practically, the 

 arrangements of blood-vessels and cells in other respects is the same 

 as in the rabbit's liver (fig. 278). If the liver is anaemic, the intra- 



Intralobular 

 vein. 



Bile ducts. 



Interlobular 

 veins. 



FlG. 278. Section of Human Liver, showing Liver Lobules and the Radiate Arrange- 

 ment of the Hepatic Cells from the Centre of each Lobule, x 20. 



lobular blood-capillaries are narrow, and the liver-cells appear to 

 compress and narrow them. 



4. Liver of Frog or Newt. Harden a small piece in absolute 

 alcohol or J per cent, osmic acid (24 hours). Stain the mass "in 

 bulk" in Kleinenberg's logwood or borax-carmine, and mount in 

 balsam. Mount the osmic acid sections in Farrant's solution with- 

 out staining, or stain them in safranin (48 hours). 



(a.) (L) Observe the anastomosing system of gland-tubes made 

 up of hepatic cells. Between them the narrower blood-capillaries, 

 many of them filled with blood-corpuscles. Here and there black 

 patches of pigment melanin especially in winter frogs (fig. 279). 



(/;.) (H) Each cell is polygonal, with a large spherical nucleus ; 

 the contents may be more or less granular, according to the phase 



