Archibald explains the effectiveness of cholecystec¬ tomy by hazarding the guess that the operation removes the only muscular force of any strength in the biliary system. But, unfortunately, the operation of cho¬ lecystectomy is followed by a general dilatation of the ducts, which must mean that there has been an increase of pressure ; therefore, if cholecystectomy is of value, it must be because Archibald is wrong. If he is correct,