The expe;iments reported here are part of a , larger study whose goal is to explore certain mechanisms involved in the mobilization of the organism's defenses against injury. This latter term is used to cover a wide range of trauma which result in pathology, extending from psychological stress to various kinds of bacterial, toxic, and neoplastic agents. In the studies in this paper, mobilization of defenses is isolated in the recovery processes following upon tissue damage in the form of surgical excision wounds. Recovery from this type of insult represents a basic adjustment of the organism and is a paradigm for the important physiological activities involved in repair of tissue damage. This repair process is essentially the same whether it be in tissue destruction secondary to tuberculosis, gastric ulcer, or mechanical injury. Previous studies ( 5 , 8, 9, 10) have demonstrated the effect of cortisone, antireticulo-cytotoxic serum (ACS) and somato-trophic hormone (STH) on wound-healing. The results indicated that the inhibition in the healing of a wound probably arises from common underlying mechanisms, one of which may be an alteration in vascular tone and capillary ,permeability. These findings suggested that the same changes might be produced by emotion-arousing situations, and thus the stress might affect basic physiological adaptive processes. Other studies point in the same direction. It is claimed by Fischer ( 1 ) that serum from schizophrenic patients in stressful situations shows increased toxicity to tadpoles. Physiological damage has also been found to occur as a result of emotional stress ( 14). It was decided to look for a specific, neurogenic stress stimulus of brief duration which would not produce any obvious gross alterations in the animal and to see whether this stimulus would alter such a basic biological process as wound-healing. Audiogenic shock seemed well suited for this purpose. Furthermore, this stimulus-situation has been the center of discussion as to whether its effects arise because of its specific action on the auditory nerve and associated mechanisms' or because of its conflict-arousing quality. Comparison of the effects of audiogenic seizures, tissue injury, and conditioned "neurosis" on biological repair processes could throw light on the controversy.