CHAP. XXXIII.] PORTAL VEIN. 467 



Fig Ml. 



A small lobule from the pig's liver, showing a. the interlotralar branches of the portal ve'n, and b. a 

 portion of the lobular capillary network within the capsule injected. Each branch is seen to give off 

 small branches on either side to the adjacent lobules. After Dr. Beale. 



the name of Glisson's capsule, from its discoverer, has been stated 

 by many subsequent writers, to be prolonged into every part of 

 the gland, separating the lobules from each other, and forming an 

 investment for each, a description which we have failed to verify in 

 every mammalian animal which we have examined, except the pig, 

 where this areolar tissue is really prolonged between the lobules. 



Portal Vein. The large portal vein is formed by the union of 

 the veins of the stomach and intestines, the pancreatic and splenic 

 veins and the veins of the mesentery, omentum, and gall bladder. 

 The portal circulation has been described in p. 347, and we have, 

 therefore, only to describe the distribution of the vein in the liver. 

 The branches of the portal vein may be said, in general terms, 

 to be arranged round the lobules ; but the branches upon different 

 sides do not anastomose so as to encircle each lobule with a 

 venous ring, as many authors, following Kiernan's diagram, have 

 described and represented, but communicate with each other only 

 through the intervention of capillaries. Even in the pig there is 

 no vascular ring, although to the naked eye it might appear so. 

 In the liver of the human subject, and in livers allied to it, small 

 branches of the portal vein can often be traced from the inter- 

 lobular fissures into the lobule, breaking up into capillaries as 



