THE CIRCULATION THROUGH SPECIAL ORGANS 439 



celiac axis, and from the portal vein. The former blood-vessel 

 conveys its contents to the framework of this organ and the latter to 

 the secretory cells. It is a well-known fact that the arterial terminals 

 eventually unite with the intralobular radicles of the portal vein, so 

 that both types of blood eventually attain the common collecting tube, 

 the vena hepatica. For this reason, it must be evident that the secre- 

 tory cells of the different acini cannot be rendered absolutely bloodless 

 by the ligation of the portal vein, because a certain amount of blood 

 will still be furnished them in an indirect way by the hepatic artery. 

 In agreement with the histological evidence, Burton-Opitz^ has found 

 that the influx through the hepatic artery is always increased if the 

 portal blood is prevented from reaching the liver by diverting it directly 

 into the inferior vena cava through a fistulous communication (Eck 

 fistula) . 



The manometric determinations of Burton-Opitz^ have shown 

 that the pressure in the hepatic artery of the dog is from 4 to 6 mm. 

 Hg lower than that prevailing in the abdominal aorta, and from 5 to 

 6 mm. Hg higher than that existing in the arteria gastroduodenalis. 

 The latter blood-vessel, as has been stated previously, forms' the con- 

 tinuation of the hepatic artery. Upon the basis of numerous quantita- 

 tive determinations of the blood flow in the hepatic^ artery, it has been 

 found by this investigator that the speed of flow is 300-350 mm. in a 

 second. This value is in close agreement with similar calculations of 

 the velocity of the blood flow in other systemic arteries. The portal 

 blood stream, on the other hand, progresses with a speed of only 60 

 to 80 mm. per second. 



In the coarse of the experiments just cited it has been found that 

 the pressure in the different tributaries of the portal vein amounts to 

 about 10-14 mm. Hg and at the hilus of the liver to 8-9 mm. Hg. 

 The latter value, therefore, indicates the pressure under which the 

 cells of the liver acini secrete the bile which is then transferred into the 

 bihary spaces and capillaries in which the resistance is practically zero. 

 Moreover, as the pressure in the inferior vena cava in the vicinity 

 of the hepatic vein is close to zero, it will be seen that the resist- 

 ance which the portal blood must overcome in its passage through the 

 liver, is very slight in comparison with the resistance offered to the 

 blood of the hepatic artery. Clearly, as the latter arrives at this 

 organ under a pressure only slightly below that prevailing in the 

 abdominal aorta and leaves it under the general venous pressure, the 

 loss is considerable. It must amount to almost 100 mm. Hg. 



Quantitative measurements of the arterial influx into the liver, 

 in a dog weighing about 15 kg., have given a value close to 3 c.c. in a 

 second. Moreover, as the portal influx in the same period of time 

 amounts to about 5 c.c, the total blood supply of this organ may be 

 estimated in round numbers at about 7 c.c. per second. If this value 



1 Quart. Jour, of Exp. Physiol., iv, 1911, 93. 



2 Ibid., iii, 1910, 297. 



