THE CONTRACTILE MECHANISM OF THE GALL- 

 BLADDER AND ITS EXTRINSIC NERVOUS 

 CONTROL 1 . BY F. A. BAINBRIDGE AND H. H. DALE. 



(Eighteen Figures in Text.) 



(From the Physiological Laboratory, University College, London, and 

 the Wellcome Physiological Research Laboratories, Herne Hill.) 



Introduction. The experiments here recorded were undertaken as a 

 preliminary to a general consideration of the causes which lead to the 

 pouring of bile into the duodenum at the stage of digestion when its 

 presence is required. The investigation has proved more complicated 

 than was anticipated ; and it seems better to communicate at once our 

 observations on the contractile mechanism of the gall-bladder, reserving 

 for future discussion experiments on the actual process of secretion. 



Methods. All the experiments were made on dogs, fully anaesthetised 

 with the A. c. E. mixture, after a preliminary dose of \ 1 gr. of morphine. 

 Direct observation of the contractions of the gall-bladder was found to 

 be impossible, the movements being too slow to be accurately followed. 

 Various methods of mechanical recording were, therefore, given a 

 trial. To the obvious method of inserting a cannula into the common 

 duct and connecting with a water-manometer there are two fatal 

 objections : it is impossible to be certain that nerves coursing up the duct 

 to the bladder are not injured ; and the presence of valves in the common 

 duct makes it impossible to refill the bladder when once it has emptied 

 itself, so that a relaxation cannot be recorded. The record so obtained, 

 in fact, is merely that of the maximum pressure exerted by the gall- 

 bladder during the experiment. An attempt was made to avoid these 

 difficulties by passing a small gum elastic catheter up the common duct 

 into the gall-bladder : but, in this case, the viscosity of the bile and the 

 necessarily narrow bore of the catheter formed a combination fatal to an 

 accurate record. 



1 The expenses of this research were in part defrayed by grants from the Government 

 Grants Committee of the Eoyal Society, and the Scientific Grants Committee of the British 

 Medical Association. 



