148 PHYSIOLOGY CHAP. 



fact that both proteins and fats excite the hepatic cells and 

 accelerate the secretory function. 



(/?) Stern's experiment on pigeons (1885) is more decisive. 

 After total occlusion of the liver in these birds, by ligation of 

 all the vessels that enter or leave it, including the bile-duct, 

 urinary secretion is arrested, and bile pigments do not appear 

 either in the blood serum or in extracts of the tissues, even with 

 Gmelin's highly sensitive test. When, on the other hand, Stern 

 confined himself to occluding the bile-duct only, the pigments 

 appeared in the urine after an hour and a half, and after five 

 hours they could be detected in the blood serum. This shows 

 plainly that the bile pigments in circulating blood are formed 

 exclusively in the liver. 



(y) The experiments of Minkowski and Naunyn (1888) on 

 geese are no less important. They destroyed a considerable pro- 

 portion of the erythrocytes of two geese, in one of which the liver 

 had been excised by inhalations of arseniuretted hydrogen, and 

 observed that after half an hour the goose with a liver gave off 

 urine containing biliverdin and bile acids, while the goose with 

 no liver gave urine which contained abundance of haemoglobin 

 with no trace of pigments or bile acids. On then removing the 

 liver of the first goose, and occluding all the vessels, including 

 the bile-ducts, they noted after some time that the serum of the 

 blood contained neither bile pigments nor bile acids. These 

 experiments are complementary to those of Stern, showing that 

 not only the bile pigments but also the bile acids have an 

 exclusively hepatic origin. 



(5) The same interpretation holds for the experiments per- 

 formed by v. Fleischl with Ludwig on dogs. Having tied the bile- 

 duct and inserted a fistula in the thoracic duct, he showed that the 

 lymph that escaped from the fistula contained the constituents of 

 bile, which are absent when the bile-ducts are not occluded. On 

 tying both the bile-duct and the thoracic duct on the other dog 

 at the same moment, he saw that the latter swelled from the 

 accumulation of lymph, while no trace of bile salts could be 

 detected in the blood. This result, which was subsequently con- 

 firmed by Harley, shows not only that bile is exclusively produced 

 by the liver, but also that after occlusion of the bile-ducts it is 

 reabsorbed exclusively by the lymphatic paths to the thoracic 

 duct. Both these experiments of Fleischl and those of Minkowski 

 and Naunyn with inhalations of arseniuretted hydrogen show 

 that the haematic or extra-hepatic origin of jaundice can, under 

 no circumstances, be admitted, even where the latter is confined 

 to the accumulation of the bile pigments in the blood. The 

 presence of bile pigments in the urine of a patient invariably 

 denotes reabsorption in part at least of the bile by the 

 lymphatics of the liver. Occlusion of the larger bile-passages is 



