

THE PARENCHYMA OF THE LIFER 167 



and the elements necessary to constitute the bile are selected and 

 carried on, to be drained away by the bile -capillaries and -ducts. 



PRACTICAL DEMONSTRATION 



It is best to begin with the liver from a pig. The amount of connective 

 tissue in the normal human liver is very small, and is mainly confined to the 

 support of the interlobular vessels; the boundaries of the lobules are, there- 

 fore, poorly defined, and without the previous observation of some well outlined 

 specimen the student frequently gets but an imperfect notion of the plan of 

 the human organ. 



Pieces of liver, say a centimeter square by half a centimeter thick, are 

 hardened by twenty-four hours' immersion in strong alcohol. Larger pieces 

 may be prepared with Miiller's fluid. Sections should be cut with a microtome, 

 care being taken to include some of the medium-sized portal canals. The 

 portal vein, with its accompanying vessels, may be easily distinguished from 

 the solitary and Jess frequent branches of the hepatic veins. The elements of 

 these canals, and especially the larger ones, are best kept intact by infiltration 

 of the tissue with celloidin; but very fine sections may, with care, be made 

 from the alcohol -hardened tissue. Even free-hand cuts, after some degree of 

 skill has been obtained by practice, will answer very satisfactorily. Stain with 

 hsematoxylin and eosin. 



SECTION OF LIVER OF PIG. CUT VERTICALLY TO AND 

 INCLUDING THE CAPSULE OF GLISSON 



OBSERVE: (Fig. 109) 



(L.) 



1. The capsule of Glisson, C. (Note the prolongations sent 

 into the organ, which divide the entire structure into irregularly 

 polygonal areas if divided transversely and elongated, verti- 

 cally-sectioned areas the hepatic lobules.) 



2. The central (intralobular) veins, C. V. (Note that the figure 

 formed by the division of the vein varies according to the direction 

 of the cut, a circle, oval, or elongated slit, as the lobules have 

 been sectioned transversely, obliquely, or vertically.) 



3. The hepatic veins, H. V. (Those shown in the section are 

 undoubtedly sublobular. It must be remembered that sub applied 

 to these vessels is misleading, as the lobules are situated on every 

 side, as well as above the sublobular veins.) 



4. The portal canals, P. C. (Even the smaller ones, I, I, are 

 reactily differentiated from areas containing hepatic veins, inas- 

 much as a group of vessels can be distinguished the hepatic 

 veins running alone.) 



