461 



occurs in the gall-bladder, in the transverse fissure, and in the portal 

 canals. This disposition of the veins has the effect of ensuring free 

 circulation through them under different conditions, as when they 

 are stretched or compressed. 



The vasa aberrantia in the transverse fissure of the adult human 

 liver are nearer to the branch of the portal vein than to the hepatic 

 substance, and can be readily removed without any of the latter. A 

 few small straight branches are sometimes observed to come off from 

 the vasa aberrantia and to enter the hepatic substance. In the foetus, 

 on the other hand, the vasa aberrantia are fewer in number, their 

 course generally is more direct, they lie so close to the hepatic tissue 

 that they cannot be removed unless a portion of the latter is taken 

 away with them, and very many of the branches can be traced into 

 the hepatic substance. 



The author regards the vasa aberrantia in the adult liver in the 

 light of altered secreting tubes, and believes that at one time they 

 formed a part of the secreting structure of the liver. At the termi- 

 nation of intrauterine life the portal vein increases in size, and the 

 pressure thus produced may account for the gradual wasting and 

 partial disappearance of the hepatic substance closely surrounding 

 it. In the very thin edge of a horse's liver, which consisted prin- 

 cipally of areolar tissue, the gradual alteration of the ducts and 

 ultimate complete disappearance of the secreting cells was traced. 

 Upon the surface of the portal vein in the rabbit's liver the trans- 

 itional stages between the compact lobule of secreting structure and 

 the branches of the vasa aberrantia have been well seen. 



Function of the glands and vasa aberrantia. It has always been 

 considered that the office of the ducts was to secrete the mucus of 

 the bile, and a similar function was assigned to the vasa aberrantia 

 by Theile. It seems to the author that a cavity communicating 

 with a tube by a neck of less than 5 \, O th of an inch in diameter, 

 cannot be well adapted for pouring out a viscid, tenacious mucus. 

 If these cavities contained mucus, the injection would not enter 

 them so readily as it does, nor is it easy to conceive how the mucus 

 poured out by these little glands would become thoroughly mixed 

 with the bile as it passes along the ducts. Again, the bile of the 

 pig, in which animal these glands are very abundant, does not con- 

 tain more mucus than the bile of the rabbit, in which they are few 



