112 PRACTICAL MICROSCOPY. 



will be seen to radiate more or less distinctly from focal points the 

 central or intra-lobular veins.) 



(H.) 



9. The portal veins. (Note the fusing of the wall with the sur- 

 rounding tissue it being extremely difficult to find the line of 

 demarcation.) 



10. The lymph spaces in the connective tissue of the portal 

 canals. (Note, in those which are better defined, the nuclei of the 

 endothelium. Do not confound these lymphatics with small veins, as 

 the latter present a tolerably defined wall, while the lymphatic chinks 

 appear like rifts in the connective tissue; it would 'be difficult to 

 make this distinction without the endothelial cells, ) 



11. Hepatic arteries. (On account of its solidity, the liver will 

 enable the student to secure sections of blood-vessels presenting the 

 typical structure more nearly than the specimens obtained from the 

 organs heretofore examined.) Note (a) the elongate nuclei of the 

 sarcous elements of the media ; (ft) the fusing of the adventitia 

 with the connective tissue surrounding the artery; (c) the sharply de- 

 fined outer boundary of the intima the fenestrated membrane, 

 which, from the action of the hardening agent, has contracted the 

 elastic fibres and detached (d) the endothelial cells. (Inasmuch as 

 the lining cells of small arteries are very frequently partly detached 

 in alcohol-hardened tissue, they may simulate columnar cells. A like 

 appearance is often presented when an artery has been sectioned 

 obliquely, by the projecting muscle-cells of the media). 



12. Hepatic ducts. Note: (a) The lining cylindrical cells. 

 (b) The nuclei of these cells (as a rule, perfectly spherical; and, in 

 transections arranged in a circle, affording an appearance perfectly 

 characteristic), (c) Mucous glands in the wall of the larger ducts, 

 lined with large nucleated columnar cells, precisely like those lining 

 the duct-lumen; and, hence, liable to be mistaken for small ducts. 

 (The tube carrying the mucus secreted in these pocket-like glands 

 does not pass directly into the lumen of the duct, but runs along ob- 

 liquely, much like glands in the bronchi. Not infrequently the 

 glands possess no proper efferent tube, but are mere depressions or 

 or diverticula in the thick wall of the bile duct.) 



13. The lobular parenchyma. (Single cells, partly detached, 

 may be found about the edges of the section.) Note: (a) The some- 

 what polygonal figure ; (b) the nucleus ; (c) nucleoli ; (d) fibril- 

 lated, mesh-like cell body ; and (e) an apparent cell wall. (The 

 arrangement of the lobular parenchyma will be noted in connection 

 with the human liver.) 



