Injury and Repair Within the Sympathetic Nervous System

The postganglionic sympathetic nerve fibers can regenerate. First, Tuckett,¹in 1896, and later, Machida,²in 1929, demonstrated this clearly, with the fibers leaving the superior cervical ganglion for the eye. Observations on the return of vasomotor and sudomotor function after section and suture of a peripheral nerve, made in the experimental animal by Kilvington and Osborne,³in 1907, and on man by Head,⁴in 1920, and by Trotter and Davies,⁵in 1909, indicate that the postganglionic fibers are, indeed, among the fastest growing of the fiber components of such a nerve. Recently, however, a new method has become available by which the state of sympathetic function in surfaces relatively free from hair can be studied. By the determination of the presence or absence of action currents in the skin, either spontaneous waves in the electrical potential of the skin or the reflexly elicited galvanic skin