Illustration of the Scottish anatomist and surgeon Sir Charles Bell (1774-1842). Bell is considered to be the father of modern neurophysiology. In 1804 He moved to London where he became a well-known surgeon and lecturer on surgery. From 1807 he showed that nerves are not single units but consist of separate fibres within a common sheath. He proved that a fibre transmits either sensory or motor stimuli, but not both, and that a muscle must be supplied with both types of fibre. He discovered the long thoracic nerve (Bell's nerve) and showed that lesions of the seventh cranial nerve produce facial paralysis. Illustration from 1859.