1906.] Liver Cells to the Blood-vessels and Lymphatics. 491 



The permeability of the vessel walls, which is so marked a characteristic of 

 the intralobular blood-vessels, is also a feature of the blood-vessels at the 

 junction of interlobular connective tissue and liver parenchyma. Starling (58) 

 pointed out that the capillaries of the liver are the most permeable of all the 

 capillaries of the body. He also showed that the lymph which comes from 

 the liver contains from 6 to 8 per cent, proteids, almost as much as the blood 

 plasma itself. 



We believe that the lymph is collected at the periphery of the lobules in 

 lymphatic spaces immediately surrounding the branches of the interlobular 

 veins as they enter between the columns of liver cells ; it passes into these 

 spaces from the cells at the periphery of the lobules. In all probability the 

 intracellular plasmatic channels of the liver cells act as an intermediate 

 system linking the blood-vessels in the lobules to the lymphatics outside. If 

 this is the case the plasma must flow from cell to cell on its way to the 

 periphery of the lobule. In the injection preparations there is evidence that 

 the channels do communicate from cell to cell, although it is difficult to wash 

 the injection out of the cells by the perfusion of large quantities of salt 

 solution through the blood-vessels. But injection of the lymphatics does not 

 favour the idea that the intracellular channels open into them, for even where 

 the interlobular connective tissue is full of injection material none passes into 

 the liver cells at the periphery of the lobules. 



How, therefore, the blood plasma passes from the cells into the commencing 

 lymphatics must be left for the present undetermined. Whenever colouring 

 matter which has been used in injecting the lymphatics is found in the liver 

 cells, there is not the slightest doubt that the injection has passed -into the 

 cells from the interior of the blood-vessels, into which it has entered by 

 rupture of their walls. 



The large amount and the concentrated character of the lymph which 

 comes from the liver must be ascribed to the peculiarities of the connection 

 between the blood and liver cells and the sinusoidal character of the circula- 

 tion in the lobules, the incomplete endothelium allowing the ready passage 

 through it of fluid and even of small solid particles both into the liver cells 

 and into the lymphatics. 



Whether the endothelium possesses the power or not of altering the degree 

 of permeability is uncertain. Mayer (44) believes that the walls of the liver 

 capillaries can alter their permeability for fluid and solid constituents of the 

 blood, and this quite independently of pressure changes or vaso-motor 

 influences. The question is one which has an important bearing on theories 

 of the formation of lymph, and requires further investigation. 



If, as we believe, the liver cells lie in the direct path between blood stream 



