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length, radiating from the axis of each lobule ; these unite at various 

 points with each other, so as to present a more or less decidedly 

 plexiform appearance. Each lobule, as described by Mr. Kiernan, 

 is separated from the adjacent ones by the terminal twigs of the 

 portal vein, and to a greater or less extent by a " fissure," though in 

 most animals the lobules are continuous with each other both above 

 and below the fissure. The elaboration of the secreted product 

 seems to be most completely effected in the cells adjoining the 

 margins of the lobules, which are often seen to contain a larger 

 quantity of biliary matter than those in the interior, and to be appa- 

 rently in the act of discharging it into the fissure ; the margin of 

 the lobule then presents an irregular surface with large globules of 

 the secretion clustering together all over it. The capsule of Giisson 

 surrounding the vessels in the portal canals gives a fibrous invest- 

 ment to those surfaces of the lobules which are towards the canal ; 

 but when it has arrived in the fissures, it forms a continuous mem- 

 brane lining the surfaces of opposite lobules ; this membrane is often 

 truly homogeneous, and closely resembles the basement tissue : there 

 appears occasionally to be a delicate epithelium on its free surface ; 

 but this, as well as the membrane itself, is often absent, when the 

 margin of the lobules is in that condition which has just been de- 

 scribed and which may be termed active. The minute branches of 

 the hepatic duct as they approach their termination undergo a re- 

 markable alteration in their structure ; they lose their fibrous coat, 

 which blends itself with the membranous expansions of the capsule 

 of Giisson ; their basement membrane becomes gradually indistinct, 

 and at last ceases to exist, and the epithelial particles no longer 

 retain their individuality, but appear to be reduced to mere nuclei, 

 set very close together in a faintly granular basis substance. The 

 mode of their termination is not uniformly the same; frequently they 

 present distinctly closed rounded extremities, between one and two 

 thousandths of an inch in diameter ; at other times they seem to 

 cease gradually in the midst of fibrous tissue, the nuclei alone being 

 disposed for some little way in such a manner as to convey the idea 

 of a continuation of the duct. These ducts can seldom be dis- 

 cerned in the fissures, but have several times been seen in the 

 " spaces," where several fissures unite ; they do not form anything 

 like a plexus between the lobules. From the anatomical relation of 

 the ducts to the parenchyma, and from the circumstance that a 

 distinct vessel conveying a different kind of blood is distributed to 

 the hepatic duct, as soon as the liver assumes the parenchymal form, 

 it seems probable that the mode in which the secreted bile is con- 

 veyed out of the organ, is by its permeating the coats of the minute 

 ducts in obedience to an endosmotic attraction, which takes place 

 between the bile in which the ducts may be said to be bathed, and 

 a denser (perhaps mucous) fluid formed in their interior. The 

 large quantity of oily matter frequently existing in a free state in 

 the secreting parenchyma of the liver, which must be regarded as a 

 product of secretory action, seems to suggest the idea, that a cer- 

 tain quantity of the biliary secretion may be directly absorbed into 



