356 MODE OF INVESTIGATION OF THE LIVER. [sect. 1 63. 



matter, there is only this difficulty, viz., that, according to Remak, 

 all the hepatic cylinders, even the largest, form anastomoses; 

 whilst, as is well known, the bile-ducts ramify without anas- 

 tomosing with each other. Here we are forced to assume that 

 the anastomoses of the originally largest hepatic cylinders do not, 

 in the course of development, keep pace with the other parts, but 

 are absorbed; an assumption supported by many analogous phe- 

 nomena of foetal development. There would appear, however, to 

 be an exception to this in man (and in some animals, L. Beale) ; 

 for it seems to me, that the above-mentioned anastomoses of the 

 right and left hepatic duct in the fossa hepatis, as described by 

 E. H. Weber, are satisfactorily explained by the observations of 

 Remak, and are nothing else than the embryonic anastomoses of 

 the rudiments of these canals, which have advanced to a certain, 

 though not considerable degree of development. According to 

 Remak, the gall-bladder in the chick is, at first, a solid outgrowth 

 of one of the bile-ducts, which subsequently becomes hollow, and 

 quickly enlarges. I observed the folds of its mucous membrane 

 in a human foetus of five months. - 



In the investigation of the liver it is best to commence with that of the pig, 

 in which animal the distinct separation of the lobules very much facilitates 

 the understanding of the relations of the secreting parenchyma to the vessels 

 and ducts. The hepatic cells can be isolated in all animals with the greatest 

 readiness, either singly, or in rows, or as fragments of the network ; in order, 

 on the other hand, to understand correctly their- general arrangement, there 

 is no better plan than to make fine sections uf a fresh liver with the double 

 knife, which are far superior to those made in the ordinary way with a razor, 

 even when the liver has been previously hardened in alcohol, pyroligneous 

 acid, chromic acid, etc. We do not, however, mean to say that the hepatic 

 cell-networks cannot be seen by the latter mode of preparation, for they can 

 be perceived even in opaque parts of the liver when viewed by reflected 

 light, only that such method does not afford a perfect view of the structure. 

 The finest bile-ducts are not easy to find, still, in sections which pass through 

 several lobules, fragments of them, which are readily recognisable by their 

 small polygonal cells, may be perceived, on careful examination, at the border 

 of the lobules, almost in every preparation ; and perhaps, after long-continued 

 investigation, such a fragment may be seen in connection with the hepatic 

 cell-network, though I have not, hitherto, been so successful as to observe 

 this. The larger bile-ducts present no difficulties. Their glands are readily 

 seen, partly with the naked eye, partly with a lens after the addition of caustic 

 soda ; and the Weberian anastomoses of the two hepatic ducts in the fossa 

 transversa, may be discovered in good injections. The vasa aberrantia, in the 

 lig. triang. sinistrum, and in other places, are perceptible without injection, 

 after the addition of acetic acid or caustic soda. The nerves and lymphatics 

 of the liver are also, up to a certain point, readily seen in man. The blood- 

 vessels require good injections, and for this I recommend the livers of chil- 



