Abstract
The role of the vagi in gall-bladder contraction was studied in conscious dogs with chronic biliary fistulae. The interdigestive periodic contraction of this organ was abolished by bilateral cervical vagal blockade, atropine or pentolinium, but neither methacholine nor carbachol initiated contraction when the duodenum was kept alkaline. The orthodox view that gall-bladder evacuation is primarily controlled by humoral mechanisms needs re-evaluation. Vagal blockade prevented the usual gall-bladder contraction in response to duodenal acidification.