116 PHYSIOLOGY AT THE FARM. 



system from the veins of the chylopoetic organs, and of the 

 venous blood formed in the liver itself, and supplied in the 

 lobules by the capillaries of the hepatic artery to the capil- 

 laries of the portal vein. Finally, the venous twig first re- 

 ferred to, descending through the lobule to the larger twig on 

 which the lobule rests, receives the residual blood after the 

 secretion of the bile within the lobule, and the twig of the 

 hepatic duct, which passes from the surface to the nearest por- 

 tal canal, carries away the bile so secreted, to throw it into 

 larger and larger ducts running in the larger portal canals. 



Secretion of Bile. Thus the bile is secreted within these 

 lobules from the venous blood collected from all the chylo- 

 poetic organs, not excepting even the liver itself; and after the 

 bile has been separated, the residual large quantity of venous 

 blood is conveyed by the hepatic system of veins to the veins 

 termed vense cavse hepaticae, by which it is poured into the 

 abdominal cava just as it is about to terminate in the heart 

 itself. 



Besides the blood-vessels and ducts connected with the 

 lobules, there are hepatic cells. These are nucleated cells 

 that is to say, minute closed cells, in the walls of which 

 severally there is a corpuscle or nucleus. These cells are of 

 extreme minuteness, their diameter being only two or three 

 times longer than that of the blood-corpuscles. These cells 

 are doubtless concerned in the secretion of the bile ; yet there 

 are none found to be contained in the bile when carefully exa- 

 mined. These cells, or hepatic corpusqles, occupy the inter- 

 stices between the blood-vessels and the commencement of the 

 biliary ducts in each lobule. The matter composed of these 

 corpuscles or cells is sometimes termed the hepatic substance. 



The bile of the ox has often been examined with much care 

 by chemists of the greatest eminence. According to the most 

 recent views, it may be considered to be a variety of soap, 



