518 Drs. P. T. Herring and S. Simpson. [May 1, 



was recorded. In a curarised dog the maximum pressure attained was 

 146 mm. bile. In a rabbit a pressure of from 163 to 168 mm. bile was 

 recorded, in another rabbit 115 mm. bile was the maximum, while in a third 

 rabbit a maximum pressure of 242 mm. bile was reached. 



In Hermann's ' Handbuch der Physiologie,' Heidenhain (9) gives the 

 secretion pressure of bile in five dogs as varying from 110 to 220 mm. of a 

 solution of sodium carbonate. A simultaneous measurement of blood-pressure 

 in a branch of the superior mesenteric vein in each of these animals gave 

 figures varying from 50 to 90 mm. of a solution of sodium carbonate. From 

 these figures and those of Friedlander and Barisch, Heidenhain concluded 

 that secretion of bile is not a mechanical effect of blood-pressure in the liver, 

 but a vital act, and that the pressure of secretion is produced by the activity 

 of the liver cells. Heidenhain showed, moreover, that the maximum pressure 

 reached in any case is not an absolute measurement of the force that the liver 

 cells can exert in secretion, but is rather the pressure at which bile secretion 

 is balanced exactly by bile absorption. 



Most text-books of physiology give Heidenhain's figures. Afanassiew (1) 

 is stated to have recorded the maximum pressure in dogs as 275 mm. bile. 



Eichet(15) gives the maximum pressure in cats as varying between 

 158 and 264 mm. bile. These figures appear to be taken from the results of 

 experiments by Kowalewsky (12), who finds the pressure varies from 

 12 to 20 mm. Hg. in curarised cats. 



In 1905, Freese (3) measured the force of contraction of the gall bladder in 

 dogs. He introduced a cannula into the gall bladder through the common 

 bile duct and cystic duct, then tied a ligature round the common duct near 

 the duodenum. Stimulation of the splanchnic nerve caused contraction 

 of the gall bladder sufficient to support a column of Einger's solution 214"5 to 

 313 mm. high. The method does not appear to have excluded the secretion 

 pressure of bile. Ligature of the common bile duct near the duodenum must 

 have brought about a rapid rise of pressure in the bile passages which would 

 be transmitted to the interior of the gall bladder. It is possible that some 

 of the pressure changes in Freese's experiments, ascribed by him to the 

 musculature of the gall bladder, may have been due to changes in the rate 

 of secretion and absorption of bile in the liver. 



Methods employed in the Present Research. 



The animals were anaesthetised with chloroform. Tracheotomy was then 

 performed, and the anaesthetic subsequently continued by a tracheal tube. 

 In some cases ether was employed after the chloroform. In all experiments 

 the animals were kept deeply under the anaesthetic and killed by an overdose, 



