34° PARENCHYMA OF THE LIVER. [SECT. 159. 



is altogether peculiar in respect of the structure of the secerning 

 parenchyma, which prepares the gall. The parts which constitute 

 and belong to it are — the secreting parenchyma, consisting of 

 the lobules of the liver and the networks of the hepatic cells ; the 

 biliary passages which are formed in this, and the efferent bile- 

 ducts ; very numerous blood-vessels ; a considerable number of 

 lymphatics and nerves ; lastly, a covering of peritoneum. 



§ 159. Secreting Parenchyma, Hepatic Lobules, and Hepatic 

 Substance. — If the natural surface or a section of the human liver 

 be examined, it usually presents a spotted appearance, and mostly 

 in such a manner, that small red or brown spots, of a stellate 

 shape, are surrounded by a more yellowish-red substance — medul- 

 lary and cortical substance (Ferrein) — which colouring arises only 

 from the usually unequal distribution of the blood in the small 

 vessels and capillaries; and, in quite fresh and healthy livers, 

 gives place to a uniform reddish-brown colour. The human liver, 

 as E. H. Weber, 1842, first showed, has no insulated lobules, to 

 the assumption of which the often regularly spotted appearance 

 has led ; and so much the more, as they are found very well 

 marked in an animal often submitted to investigation — the pig ; 

 but in man, the secerning apparatus, as well as the most important 

 parts of the vascular system, i.e., the capillary networks, situated 

 between the portal and hepatic veins, are most intimately connected 

 throughout the whole liver. Nevcrtheless,we should be very much 

 mistaken, if we were to regard the secerning hepatic parenchyma 

 as being everywhere uniform. There exist in it certain ultimate 

 divisions, which, although by no means insulated from each other, 

 still possess a certain independence. These hepatic lobules, as they 

 may still be called, when the word is understood in a less strict 

 sense, or hepatic islets (Arnold), arise in the following way, viz., 

 1, the smallest trunks of the efferent and afferent blood-vessels, 

 the venoe inter- and intra-lobulares (Kiernan) are distributed at 

 pretty equal distances through the whole liver, so that a piece of 

 hepatic substance, of -\"'> V" to 1" in diameter, invariably gives 

 origin in its interior to a small root of the hepatic vein, and 

 receives from without, i.e., at its circumference, a certain number 

 of the finest branches of the portal veins and hepatic artery ; 2, 

 the commencement, also, of the excretory canals or hepatic ducts 

 are not irregularly scattered in the parenchyma, but are so 

 arranged that they always begin at a distance of \'" to £"' from 

 the commencement of the hepatic veins, and run with the finest 



