Basing themselves on 149 cases, the authors describe the spinal neurophysiology of ejaculation in spinal man, and put forward certain hypotheses. They suggest that the reflex of seminal emission is a lumbar reflex, which may be dependent on conductive factor originating in the upper neurological structures, and that the orthosympathetic system, which leaves the spinal cord through the thoracolumbar junction, could provide a highway for the psychological nerve impulses inducing seminal emission.