468 Royal Society : — 



In the foetus, tlie cells are seen to be separated from the cavity of 

 the vessels by two lines separated by a clear space. One of these 

 lines is caused by the outline of the tube containing the cells, the 

 other is that of the capillary wall. 



'J'he author supposes that, originally, the liver is composed of a 

 double network of tubes (cell-containing network and capillary net- 

 work), the walls of which in most situations become incorporated, 

 so that the secreting cells are only separated from the blood by one 

 thin laj'er of basement membrane, which is very permeable to water 

 in both directions, but the greatest force which can be applied with- 

 out causing rupture is incapable of forcing bile through it. 



Of the contents of the tubular network of basement membrane, and of 

 the arrangement of the cells inithin it. 



Within the tubular network lie the hepatic cells, with a certain 

 quantity of granular matter and cell debris, and, in some instances, 

 free oil-globules and granules of colouring matter. The cells are 

 not arranged with any order or regularity. Some observers have 

 endeavoured to show that the hepatic cells are arranged in a definite 

 manner. Professor Lereboullet, one of the latest writers on this 

 subject (1853), describes the cells as forming double rows. The 

 two rows of cells may be separated by injection, and he gives two 

 diagrams to illustrate their arrangement. The author has never 

 seen anything like this in any liver which has been examined by 

 hira. In Mammalia, according to his observation, the cells are for 

 the most part arranged in single rows (human subject, pig, dog, cat, 

 rabbit, horse, seal. Guinea-pig and others), but in some situations 

 two cells lie transversely across the tube, and they may be forced 

 into this position by injection. The cells do not completely fill the 

 tubes, and are not always placed quite close together, being sur- 

 rounded with granular matter. Injection passes sometimes on one 

 side of the tube, and sometimes upon the other ; often it entirely 

 surrounds a cell. In the human foetus and in the foetal calf there 

 are two or three rows of cells within the tubes, and this is also the 

 case in the livers of most adult reptiles and fishes which have fallen 

 under the author's observation, and in many parts of the network of 

 the bird's liver. 



Of the Ducts of the Liver. 



The duct, like the artery, lies close to the portal vein ; usually 

 this vessel is accompanied by one branch of the artery and duct, but 

 not unfrequently there are two or three branches of these vessels 

 witli the vein. 



Anastomosis of the ducts near the trunk from which they come off. — 

 The author observes that the anastomoses between the larger ducts 

 and between the larger branches of the interlobular ducts are pretty 

 numerous in the human liver, but these communications take place 

 only near the origin of the trunks by means of intermediate branches. 

 Different interlobular ducts do not anastomose with each other, but 

 the branches resulting from the division of a small trunk are often 

 connected together. 



