Abstract
Rhythmical spontaneous contraction of the external anal sphincter and bulbo-cavernous muscle in unanaesthetized spinal dogs is inhibited by quickly increasing internal pressure in the urinary bladder. From experiments of dividing and stimulating the pelvic and hypogastric nerves, the nervous pathways for this reflex were found to be as follows.(1) Afferent nervous pathways run through both the pelvic and hypogastric nerves, enter the spinal cord through the posterior root of the lumbar and sacral cord.(2) Efferent nervous pathways from the spinal cord run through the pudendal nerves.