1906.] Liver Cells to the Blood-vessels and Lymphatics. 481 



the lymphatics of the liver are, in our opinion, confined to the obvious 

 connective tissue which accompanies the branches of the portal and hepatic 

 veins ; the appearances described by MacGillavry are produced by artificial 

 rupture into the blood spaces. 



The parenchyma of the normal liver contains little or no connective 

 tissue ; fine fibrils, the " Gitterfasern " of Kupffer, have been shown to exist 

 by many observers, but they are extremely fine and closely applied to the 

 liver cells. We can find no evidence of the existence of any perivascular 

 connective-tissue cells in the lobules. The " Gitterfasern " are more evident 

 in man and the dog than in the cat and rabbit. In the two latter animals it 

 is often impossible to observe any indication even of an endothelial outline 

 between the blood and the liver cells, except where Kupffer's cells occur. 

 Minot has shown that the connective tissue appears late in the development 

 of the liver, and that it is accompanied by the appearance of true capillaries 

 which grow from the hepatic artery. To us it seems probable that the 

 lymphatics of the liver have a similar distribution, and are specially related 

 to the hepatic artery and its branches. As has already been stated, Minot 

 has shown that the blood spaces of the liver are originally sinusoids, and one 

 of the characters of a sinusoid is the non-occurrence of connective tissue 

 between its wall and the adjacent parenchyma. Under these circumstances 

 the wall of the blood space is closely applied to the (liver) cells and there is 

 no natural cleft between them, nor is there, as in other secreting glands, an 

 intervening lymph space. And if, as appears certainly to be the case in some 

 animals, the endothelial wall of the blood space is itself deficient or is only 

 represented by the isolated cells described by Kupffer, the liver cells must be 

 in direct communication with the blood and the blood plasma, and even 

 under some circumstances blood corpuscles may pass directly into the cells. 



It is known that a large amount of concentrated lymph comes from the 

 liver, and Eutimeyer (54) found solid particles of cinnabar in the efferent 

 lymphatics of the liver 35 minutes after a suspension of cinnabar in salt 

 solution had been injected into the external jugular vein of a dog ; a very 

 intimate relationship between blood-vessels and lymphatics must therefore 

 also exist in the liver. 



To explain this relationship, and the ready passage of injection material 

 into the liver cells, it is necessary to consider the structure of the walls of 

 the hepatic capillaries in some detail. 



The Structure of the Intralobular Blood-vessels. (Historical.) 



His (27), in 1860, described the, capillaries of the liver and remarked that 

 they differ from the capillaries of other parts of the body in that their walls 



