412 THE SOLIDS. 



Of the proofs of the existence of a lobular biliary plexus, 

 supposed to be derived from injection, it may be remarked, 

 that these are, in all probability, fallacious, the injection es- 

 caping from the extremities of the biliary ducts, and passing 

 into, generally, branches of the portal vein, from which it 

 extends irregularly into the lobular capillary plexus, and it is 

 this plexus filled with injection from the biliary duct, that 

 Mr. Kiernan, it appears to me, took for a lobular biliary plexus. 

 It still, however, must be regarded as a singular circumstance 

 that the injection should so generally pass, after its escape 

 from the ducts, into blood vessels, in place of becoming extra- 

 vasated around the apertures of the ducts from which the in- 

 jected material has escaped. 



Presuming it, then, to be concluded that there is no lo- 

 bular biliary plexus, let us next inquire in what manner the 

 biliary ducts do really terminate. 



From the further researches of Dr. Hanfield Jones, con- 

 tained in a recent paper communicated to the Royal Society, 

 and entitled " On the Structure and Development of the 

 Liver," it would appear that the biliary ducts terminate in the 

 vertebrate series of animals in the interlobular fissures and 

 spaces in closed and rounded extremities. (Plate LVIL 



fig- 1.) 



If a branch of the hepatic duct be taken up with the forceps, 

 it may, by delicate manipulation, be dissected out from the 

 surrounding parenchymatous tissue. A branch thus prepared, 

 when placed under the microscope, will be seen to be com- 

 posed of numerous ramified biliary ducts of various sizes : the 

 extremities of the majority of these are even broken off; but 

 several are evidently entire, and these are rounded, as repre- 

 sented in Plate LVII. fig. 1. 



These ducts are not simple tubes, formed of basement meni- 

 brane, but are lined by a regular layer of epithelial scales : 

 these serve to secrete the mucus, which partly occupies them ; 

 and their presence accounts for the great difficulty expe- 

 rienced in getting the injection to flow along the ducts. 



The experiment of dissecting out a branch of the hepatic 

 duct from the parenchymatous tissue of the liver is most readily 



