Nervous discharge from small painless lesions in skin and muscle.

During an investigation of post-ischaemic paraesthesiae (Merrington and Nathan, 1949) it was noticed that during the period of ischaemia any small cutaneous lesions, such as cuts or scratches, made themselves felt, whereas they had not been noticed before. That this was no idiosyncrasy of the present author was shown by the case of a laboratory technician who had dermatitis due to formalin; he was surprised to find that shortly after the application of the cuff he felt every lesion on his fingers, although he had not previously noticed their presence. It was then considered that this phenomenon ought to be investigated at some later time. When Armstrong, Dry, Keele, and Markham (1951) published their method of producing fairly standardized blisters by cantharidin plaster, it was seen that these blisters could be used for the investigation of this phenomenon. The purpose of this study has been to investigate the pain that may arise from a previously painless lesion when the limb is rendered ischaemic, and to relate this phenomenon to other relevant knowledge.