set phrases, such as "Good bye" and "Oh, dear." In his youth Jackson had been interested in conceptual issues and it is believed that in 1859 he contemplated the idea of abandoning medicine for philosophy. Thus, an important part of his work concerned the evolutionary organization of the nervous system for which he proposed three levels: a lower, a middle, and a higher. At the lowest level, movements were to be represented in their least complex form; such centres lie in the medulla and spinal cord. The middle level consists of the so-called motor area of the cortex, and the highest motor levels are found in the prefrontal area. The higher centres inhibited the lower ones and hence lesions thereat caused 'negative' symptoms (due to an absence of function). 'Positive' symptoms were caused by the functional release of the lower centres. This process Jackson called 'dissolution', a term he borrowed from Herbert Spencer. The 'positive-negative' distinction he took from Sir John Reynolds. Continental psychiatrists and psychologists (e.g. Théodule Ribot, Pierre Janet, Sigmund Freud, Henri Ey) have been more influenced by Jackson's theoretical ideas than their British counterparts. During the 1980s, the 'positive-negative' distinction was introduced in relation to the symptoms of schizophrenia. He was one of only a few physicians to have delivered the Goulstonian (1869), Croonian (1884) and Lumleian (1890) lectures to the Royal College of Physicians. He also delivered the 1872 Hunterian Oration to the Hunterian Society. Methodology Jackson could not use modern sophisticated neuro-investigative technology (it had not been invented), but had to rely upon his own powers of clinical observation, deductive logic and autopsy data. Some of his eminent successors in the field of British neurology have been critical of many of his theories and concepts; but as Sir Francis Walshe remarked of his work in 1943, " ... when all that is obsolete or irrelevant is discarded there remains a rich treasure of physiological insight we cannot afford to ignore." In Otfrid Foerster's research on the motor cortex, he cites exclusively Hughlings Jackson for the initial discovery (although without evidence) of the brain as the spring of neurological motor signalling. Contributions Together with his friends Sir David Ferrier and Sir James Crichton-Browne, two eminent neuropsychiatrists of his time, Jackson was one of the founders of the important journal Brain, which was dedicated to the interaction between experimental and clinical neurology (still being published today). Its