548 SPECIAL HISTOLOGY. 



The investigation of the liver is best undertaken in the Pig, in which 

 animal the distinct demarcation of the lobules greatly facilitates the 

 comprehension of the relations of the secreting parenchyma, to the ves- 

 sels and hepatic ducts. The hepatic cells may be isolated with the 

 greatest ease in all animals, either singly, in series, or in reticulated 

 fragments ; but to comprehend rightly their collective arrangement no 

 better means exist than the making of fine sections in a fresh liver with 

 the double knife, for which, sections made off-hand with a razor, even 

 in a liver previously hardened in alcohol, pyroligneous acid, chromic 

 acid, &c., are by no means sufficient substitutes. We do not mean to 

 say that the hepatic-cell-network cannot be seen at all in this manner, 

 for it is visible even in opaque sections of liver by reflected light, but 

 merely that no complete view can thus be obtained. The finest hepatic 

 ducts are not readily found, though a careful search in nearly all sec- 

 tions which include many lobules, will almost certainly detect scattered 

 fragments of them, readily recognizable by their small polygonal cells, 

 at the edges of the lobules, and long examination may perhaps eventu- 

 ally discover such a fragment in connection with the hepatic-cell-net- 

 work, which, however, I have not yet succeeded in doing. The coarser 

 biliary ducts present no difficulties. Their glands are seen readily, 

 partly with the naked eye, partly by the use of dilute caustic soda. 

 Weber's anastomoses of the two hepatic ducts in the fossa transversa, are 

 visible in good injections. The vasa aherrantia, in the left triangular 

 ligament and in other localities, are readily perceived even without in- 

 jection, on the addition of acetic acid or of caustic soda. The nerves 

 and lymphatics of the liver are, except their finest portions, easily seen 

 in Man. The bloodvessels require good injections, for which purpose, 

 in the human subject, I especially recommend children's livers, in which 

 the distribution of the arteria hepatica in the serous coat, on the ves- 

 sels, &c., is beautifully distinct. The capillary network of the lobes 

 may readily be filled with fine injection, and a series of excellent pre- 

 parations of this kind, by various masters of the art, are everywhere 

 to be met with. 



. Liter-atwe of the Liver. — F. Kiernan, " The iinatomy and Physio- 

 logy of the Liver," in " Phil. Trans.," 1833 ; E. H. Weber, " Annotat. 

 Anat. and Physiol.," Prol. VI. VII. and VIII. Lips. 1841 and 1842, 

 and "Programmata collecta Fasc," II. Lips., 1851; " Ueber den 



and, that the first rucnment of the excretory apparatus is the gall bladder, whence ducts 

 extend on the one hand into the intestine, and on the otlier into the liver. He has not 

 traced the development of the liver in Mammalia. 



Vogt, however (Embryogenie des Saiimons, p. 175), states that in Cwcgonus palea, the 

 liver is at first a rounded, solid mass of cells, in contact with a diverticulum of the intes- 

 tine — the future ductus choledochus ; and that, in the course of development, the diverticulum 

 grows into and ramifies in the mass— its ultimate branches terminating in cceca. The gall- 

 bladder is not formed till very late. — Trs.] 



