Although the somatic nerves are still regarded as the mediators of afferent impulses, there has been an accumulation of evidence to show that the sympathetic system possesses a sensory function and is concerned in the production of certain types of intractable neuralgia. It is the objective of this paper to outline the conclusions of certain experimental and clinical observations, illustrating the afferent associations of the sympathetic system, and to correlate these facts with the results of sympathectomy for severe neuralgic conditions. RESIDUAL SENSATION AFTER SOMATIC DENERVATION Surgical intervention has shown that in cases of intractable neuralgic crises in which there has been an extensive division of the posterior spinal roots the resultant anesthesia is often incomplete, and the pain has persisted. Foerster's1 results for the gastric crises of tabes dorsalis were 49 per cent cure and 51 per cent failure or partial relief only. In two of Thorburn's cases,