147 



In Mammalia the subject of inquiry has been chiefly the follow- 

 ing, viz. to ascertain how far there was evidence that the secretion 

 of bile actually is effected in and by the hepatic cell, or whether its 

 presence in them is accidental, and the bile is really and necessarily 

 secreted by the ultimate ducts. 



It is remarked that the existence of a portal vein conveying blood 

 from the intestinal surface is coeval, not with the formation of a 

 bile-secreting structure (for many animals have organs which 

 secrete abundance of biliary matter without any portal vein), but 

 with the addition of a parenchymatous mass to the biliary organ, to 

 which mass exclusively the portal vein is distributed. It is known 

 that the parenchyma of the liver during, and for many hours after, 

 digestion of food, forms, from the blood supplied to it, abundance of 

 sugar, which thus appears to be its proper secretion ; and it is not 

 proved that the hepatic cells in a healthy state contain biliary matter, 

 though they often do in various morbid conditions. Extracts of the 

 hepatic parenchyma tested for bile by PettenkofFer's method, give 

 only very imperfect and doubtful traces of the presence of biliary 

 matter, and on the other hand the sugar formed by the parenchyma, 

 which is found so abundantly in the blood of the hepatic vein, is 

 absent from the bile. The case of fatty liver, as occurring either 

 pathologically or normally, seems also to require an explanation 

 consonant with the view to which the above facts point, for other- 

 wise it seems impossible to understand how perfectly formed dark- 

 green bile could be contained in the efferent channels of a gland 

 whose tissue is a mass of oil. 



The structural condition of the ultimate biliary ducts is compared 

 to that of the epithelium of the thyroidal cavities, and the nucleated 

 granular tissue surrounding the lacteal in a villus ; and it is shown 

 to be probable that the terminal portions of the ducts, — so far as they 

 possess the peculiar characteristic structure, exert an active elabo- 

 rating energy, by means of which bile is formed or generated out of 

 oily, albuminous or saccharine material which surrounds,— may be 

 said to bathe them. 



February 5, 1852. 



SIR JOHN F. W. HERSCHEL, Bart., V.P. in the Chair. 



The following papers were read :— • 



1. "Discovery that the veins of the Bat's wing, which are fur- 

 nished with valves, are endowed with rythmical contractility, and 

 that the onward flow of blood is accelerated at each contraction." 

 By T. Wharton Jones, F.R.S., Fullerian Professor of Physiology 

 in the Royal Institution of Great Britain, &c. Pveceived November 

 20, 1851.' 



The author finds that the veins of the bat's wing contract and 

 dilate rythmically, and that they are provided with valves ; some of 

 which completely oppose regurgitation of blood, others only par- 



