THE IMMEDIATE REALM OF NEUROLOGY 1 The Domain of Nervous and Mental Disease: Confounding Concepts In the nineteenth century, advances in social and economic conditions and in biomedical science encouraged physicians in Europe, England and North America not only to seek greater understanding of the organic basis of the most severe forms of mental illness or insanity but to increasingly attend to the whole domain of nervous and mental disease. This domain extended on the one hand from overt and obvious organic disorder free of mental or behavioral components, through organic cerebral disorders associated with severe cognitive and/or psychic disturbance, to disorders with clinical features strongly suggestive of organic cause but without detectable structural pathology, and to mild disorders clearly of psychic etiology on the other. In Germany and France particularly, gross anatomic and histopathologic studies were uncovering organic causes for an increasing proportion of the insanities; however, a very large and heterogeneous group of disorders remained, for which correlations with structural change could not be established. This included disorders now recognized as primarily organic (such as epilepsy and movement disorders) as well as disorders primarily psychic in origin, all of which came to be referred as "functional". At the turn of the nineteenth century, this group of disorders were conceptualized in "romantic-philosophic-psychologic" terms 23 implicating lifestyle and ideology in etiology. By midcentury, increased knowledge of nervous system anatomy and physiology encouraged a somatic view strongly espoused by Griesinger and Meynert among others, a view that was extended by some to all disorders with psychic symptoms. The approaches to the investigation and care of this vast domain of nervous and mental disease that now seem rational were seriously confounded by the very limited knowledge of disease mechanisms. In spite of the multiplicities of etiology and pathogenesis now recognized, which permit great precision in diagnosis, physicians concerned with the nervous system continue to experience difficulty in assigning somatic and psychic mechanisms to individual patients. Those whose disorders are of primary organic etiology continue to be mistakenly treated as though the cause was psychic and vice versa. This clinical challenge of distinguishing organic from psychic could only have been compounded many fold at the turn of the century, when neurology first appeared in Toronto. Contending Specialists In Europe, the British Isles and the United States, the evolution of systems for the care and investigation of this great domain of nervous and mental disease differed. Groups with different professional backgrounds began to contend roles in the management of the domain.