1906.] Liver Cells to the Blood-vessels and Lymphatics. 479 



in intralobular lymph clefts, largely because he could not find any other 

 connection between portal and hepatic lymphatics. Disse described large 

 lymphatic trunks lined by endothelial cells which run in connective-tissue 

 septa between the adventitia of the hepatic veins and the connective tissue 

 surrounding the branches of the portal vein, but he did not emphasise the 

 fact that the lymphatics also accompany the branches of the hepatic artery. 



The plexus of lymphatic vessels in the adventitia of the hepatic veins 

 follows them to their small branches, and lymphatics are present wherever 

 there is an appreciable amount of connective tissue in the wall of the vein. 

 In transverse section of the smaller hepatic veins several lymph vessels 

 (fig. 15) are seen in their walls. The number of these channels varies, as 

 Budge stated, according to the size of the vein they surround ; the larger the 

 vein the greater the number of lymphatics in its wall. 



We have employed Fleischl's method of injection in several experiments, 

 using the same apparatus as before, but removing the liver from the body 

 and introducing the point of a fine cannula, into the adventitia of one of 

 the hepatic veins. The injection mass causes a local distension of the wall 

 of the vein, and some extravasation takes place, but the injection gradually 

 finds its way into the lymphatics and appears at the portal fissure. The 

 extent of liver injected by this method is very small. Disse, in his 

 injections, made several punctures in different places, and noted the small 

 areas of liver injected. This is readily explained, and is what one would 

 expect. The lymphatics of the large branches of the hepatic veins have 

 frequent and large communications with the lymphatics of the branches 

 of the portal vein, and the injection mass has a ready means of escape and 

 soon appears in the large efferent trunks at the portal fissure ; it spreads 

 very little and simply follows the large lymph channels. The natural 

 flow of lymph from the hepatic veins in all probability takes the same course. 

 Very little spread of injection mass is seen towards the inferior vena cava, 

 and our observations point to the probability that most of the lymph of the 

 liver in the dog and cat emerges at the portal fissure. 



It has been mentioned already (p. 476) that after injection of the portal 

 lymphatics some of the lobules, especially those in the neighbourhood of 

 the portal fissure, contain injection mass, and present appearances similar 

 to those figured by MacGillavry. On careful examination of well-fixed 

 specimens in thin sections it is apparent that the injection is undoubtedly 

 inside the blood-vessels, not only in the intralobular vessels, but in 

 neighbouring interlobular branches of the portal vein as well. Sometimes 

 the periphery only of a lobule shows the injection, extending inwards a little 

 way from the portal space ; in such cases the interlobular portal vein nearly 



