530 



THE LIVER 



[CH. XXXV. 



Pfliiger and Kupffer later discovered that the relation between 

 the hepatic cells and the bile canaliculi is even more intimate, 

 for they demonstrated the existence of vacuoles in the cells com- 

 municating by minute intra -cellular channels with the adjoining bile 

 canaliculi (fig. 365). 



/7im-cellular canaliculi in the liver-cells are not unique. Eecent 

 research by Golgi's method has shown that in the salivary and 

 gastric glands, and in the pancreas, there is a similar condition. 



FIG. 365. Sketches illustrating the mode of commencement of the bile canaliculi within the liver- 

 cells (Heidenhain, after Kupffer). A, rabbit's liver, injected from hepatic duct with Berlin blue. 

 The inter-cellular canaliculi give off minute twigs which penetrate into the liver-cells, and there 

 terminate in vacuole-like enlargements. B, frog's liver naturally injected with sulph-indigotate of 

 soda. A similar appearance is obtained, but the iutra-cellular canaliculi are ramified. 



Schafer has further demonstrated that the liver-cells contain not 

 only the intracellular bile canaliculi, but also intracellular blood canali- 

 culi passing into the cells from the capillaries between them. These 

 are too minute to admit blood-corpuscles. The liver-cells take certain 

 materials from the plasma and elaborate the constituents of the bile, 

 the bile-salts, and the bile pigments. There can be no doubt that 

 these substances are formed by the hepatic cells, for they are not 

 found in the blood nor in any other organ or tissue ; and after extirpa- 

 tion of the liver they do not accumulate in the blood. We thus see 

 that in the liver, lymph does not act as a middleman, as it does in 

 the formation of other secretions. 



The functions of the liver are connected with the general metab- 

 olism of the body, especially in connection with the metabolism of 

 carbohydrates (glycogenic function) and of fats; its relationship to 

 the metabolism of nitrogenous material (formation of urea, uric 

 acid, etc.), we shall discuss with the urine. Another function is the 

 formation of bile, which it will be convenient to take first. 



