THE LIVER. 535 



connection only takes place upon the surface of the hepatic islets and not 

 in their interior, and that, therefore, the bile which is formed here, must 

 be transmitted outwards from cell to cell. Such a process of transmis- 

 sion through closed cells, involves, as vegetable physiology teaches us, 

 no impossibilities; but it can hardly take place so rapidly as in those 

 localities where actual canals subserve this purpose. Since the bile, as 

 late investigations tend to show with increasing clearness, is not only 

 excreted from the blood, but absolutely formed in the liver, and is at the 

 same time by far the most complicated of all the secretions, it may be 

 presumed that the peculiar arrangement of the secreting parenchyma 

 in the liver stands in relation with these peculiarities. In fact, the 

 plasma of the blood, in passing through many cells and being subjected 

 to the metabolic influence of each before it reaches the efferent duct, 

 must undergo very different changes from those which it suffers when 

 it is separated from the glandular canals only by a single layer of cells 

 and one or two structureless membranes. The resulting necessary 

 slowness of the secretion is compensated by the size of the organ and 

 the elaboration of the product. 



If nitric acid be added to the hepatic cells, they assume a greenish- 

 yellow color, as was originally stated by Backer. Sugar and sulphuric 

 acid turn them red ; water produces an abundant precipitate of dark 

 granules in the cells, which are usually, readily and completely soluble 

 in acetic acid, so that they become more or less pale, often to a consi- 

 derable extent ; the same thing occurs if the acid be added directly. 

 If the liver be boiled, its parenchyma becomes hard and the cells ac- 

 quire a concentrated and wrinkled appearance. Dilute caustic alkalies 

 rapidly attack the hepatic cells in animals, and dissolve them ; in man 

 they resist somewhat longer, but from the very first swell up to about 

 twice their size, become very pale, and eventually also disappear. 

 Ether and alcohol render the cells smaller and granular, as do sulphuric 

 and nitric acids. The result of these and the above-mentioned facts is, 

 that the hepatic cells contain a considerable quantity of nitrogenous 

 substances, fat, coloring matter of the bile, and perhaps also its acids. 

 The nitrogenous compounds are of several kinds : albumen, which is met 

 with in the watery extract of the liver, and a substance which is preci- 

 pitated by water, is readily soluble in acetic acid and resembles the 

 casein-like matter found in the serum of the blood (Pannum in Virchow 

 and Reinhard's Archiv, b. IV. 1). The existence of the coloring matter 

 of the bile in the hepatic cells is not so much manifested by their re- 

 action with nitric acid, which is also exhibited by many other cells, as 

 by their general tint, and the frequent occurrence in them of precipated 

 coloring matter of the bile. The existence of the fatty acids of the bile 

 in the hepatic cells is not directly demonstrable, since both albumen and 

 fat become red by the action of sulphuric acid and sugar (Schultze), but 



