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MANUAL OF HISTOLOGY. 



much divided owing to the obscurity of the subject. Many (as, for 

 instance, Andrejevic some years ago) supposed the bodies of the hepatic 

 cells to be always interposed between the blood and biliary capillaries, 

 so that these two could never come into contact one with another. 

 MacGillavry, on. the other hand, believed in the interlacement and 

 weaving together of both networks in such a way as to render this 

 possible. 



The discoveries of Her ing and Eberth, however, have since given sup- 

 port to the first view, which, from our own researches, we are also led to 

 believe to be the correct one. 



But in order to understand this fully, we must examine not only the 

 complex liver of the mammal, but the gland also in a simpler form, as it 



presents itself in, other verte 

 brate animals, among which we 

 would reckon for the case before 

 us not only fishes and amphibia, 

 but also birds. 



Let us take, then, first of all 

 the liver of the amphibia, which 

 is especially instructive. Here 

 we find as, for instance, in the 

 common ringed snake that the 

 bands of cells and networks of 

 these bands are made up (as is 

 shown in fig. 504, 1) of rouleaux 

 of gland cells, bounded exter- 

 nally by blood-vessels, and con- 

 vergent towards a line biliary 

 duct running through the axis 

 of each rouleau. One of the 

 latter is in transverse section 

 comparable to an ordinary tubu- 

 lar gland clothed with unlamin- 

 ated epithelium, and possessed 

 of a very narrow lumen, each 

 blood capillary being separated 

 from the bile ducts by the full 

 height of the hepatic cells (Her- 

 ing). The livers of the batrachia, 

 also, present a similar arrange- 

 ment of parts. A side-view (2) 

 discloses between each two rows 

 of hepatic cells a long bile-duct 

 holding the axis of the bands 

 formed by these rouleaux, while 

 external to the latter the blood- 

 capillaries are situated. Nearer 

 the circumference of the organ 

 biliary ducts of greater calibre 

 are to be found clothed with low 

 columnar epithelium which has taken the place of the hepatic cells. 



Among the lower orders of vertebrate animals lateral branches on the 

 bile ducts are seen, but sparely, and the existence of blind terminations to 



Vis. 504. Ultimate radicles of biliary ducts in the 

 liver. 1. From the common snake (alter Hering). 2. 

 From the salamander (after Eberth). 3. From the 

 rabbit, a, blood-vessels; 6, hepatic cells ; c, biliary 

 capillaries. 



