Investigators have long been intrigued with the idea that the sympathetic ganglia may constitute centers for integrative activity outside the central nervous system. For the most peripherally located ganglia, those in the viscera (the myenteric and submucous plexuses, the plexuses of the bladder and heart), the importance of this concept to an understanding of the activities of the organs is equaled only by its obscurity. Morphologic studies have contributed minute details of cells and fibers, and physiologic analysis, equally clearcut facts concerning function. But the two lines of work have not, as yet, come together. For dealing with the more centrally placed and isolated ganglia of the paravertebral and prevertebral chains, more complete data are, however, available. To begin with, only the thoracolumbar portion of the sympathetic outflow from the central nervous system enters these ganglia. The parasympathetic division has no recognized share. Furthermore, the synapses in these ganglia are