REFERRED PAIN AND IN PARTICULAR THAT ASSOCIATED WITH DYSMENORRHOEA AND LABOUR

Hunter demonstrated fhat an animal could eat its food with relish while its viscera were being cut or burned, and this remarkable insensitivity of the abdominal viscera, together with the visceral peritoneum covering them, has aroused increased interest since the advent of abdominal surgery. A neurologist, Ross of Manchester (1888), was the first to suggest that disease of the abdominal, organs occasioned two kinds of pain: a true splanchnic pain felt in the diseased organ, and an associated somatic pain felt in the body wall supplied by the cerebro-spinal nerves of the same segment of the cord. Mackenzie, who -was already at work on this problem, developed the conception of referred pain, and postulated a viscero-sensory and viscero-motor reflex. Head (1893) and Hurst (1911) provided convincing evidence in favour of Mackenzie's theory, although the latter writer believed in a true visceral pain. Lennander (1903) adopted a more simple explanation, and concluded that the sensation of pain associated with disease of the abdominal organs arose in the peritoneum, its subserous coat, and, in the presence of inflammation, in the root of the mesentery, all these structures being supplied with cerebro-spinal nerves. This hypothesis, although attractive, is untenable, because it cannot explain certain facts.