1907.] The Pressure of Bile Secretion, etc. 529 



in the other livers. There has been escape into the blood vessels at the 

 periphery of some of the lobules, and the carmine gelatine has been taken up 

 by Kupffer's cells, and appears in them in the form of small round drops. 

 Kupffer's cells are greatly distended with drops near the periphery of the 

 lobule, and contain carmine gelatine in decreasing amounts towards the 

 central vein, in the neighbourhood of which they are generally free. 



The most valuable injections are those in which the bile duct has been 

 injected at comparatively low pressures so as to avoid extravasation, and yet 

 fill the interlobular bile ducts. If the pressure is higher, rupture occurs as 

 stated, but there is also the appearance of injection mass having passed out 

 of the finer interlobular ducts into connective-tissue spaces. It is probable 

 that with a high pressure of injection most of the fluid passes out in this 

 manner and so reaches the lymphatics. Heidenhain was undoubtedly right 

 in assigning the site of rupture to the fine interlobular ducts leading from 

 the lobules. When a low pressure is employed there is no trace of such 

 rupture, although the ducts are filled, yet in this case bile is escaping from 

 the liver by the lymphatics. In the rabbit's liver, where injection penetrates 

 along the bile capillaries further into the lobules, one often sees a number 

 of cells in a column suffused with diluted injection mass, as though the 

 material were passing through them in the direction of the periphery of the 

 lobule. 



The readiness with which obstruction of the bile duct is recovered from, 

 the bile again following its natural course when the obstruction is removed, 

 and the observations of Heidenhain that the bile secreted after removal of 

 the obstruction contains the same relative proportions of solids to fluid, show 

 that no permanent damage is caused by the leakage, assuming it to be 

 a leakage. One would hardly expect so complete a recovery were there 

 a mechanical rupture of the wall of the bile ducts. One must rather assume 

 that there is some physiological explanation of the absorption of bile. It is 

 possible that the walls of the interlobular ducts are capable of allowing bile 

 to pass out without any physical damage resulting, and that such passage 

 cannot occur when the internal pressure is reduced, thus acting as a kind of 

 safety valve allowing escape into the lymphatics when required. Carmine 

 gelatine, however, does not appear capable of passing out in this wayjwhen 

 injected at pressures too low to produce extravasation, but high enough to- 

 turn the flow of bile into the lymphatics. 



Escape of bile into the lymphatics, if it occurs from the liver cells 

 directly, can only be from the cells at the peripheral part of the lobule. 

 Inside the lobule the only escape possible is by the natural channels, the 

 bile capillaries, or into the fine plasmatic channels which permeate the liver 



