The scientific work of Walther Birkmayer is grounded on his ability to turn what was often a mass of clinical details into the basis for a hypothesis for a new therapeutic approach toward solving the problems of a patient's illness. Birkmayer first became known when, during the Second World War, he built up a clinic for brain injuries in Vienna, in which over 3000 patients were treated. The study of changes in the autonomic functions of the nervous system in these patients as well as the problems of rehabilitation were published in a monograph, "Hirn- verletzungen". Consequently, this was his major scientific interest during the post-war years. His book, "Klinik und Therapie der vegetativen Funktionsstorungen" published with W. Winkler, brought Birkmayer recognition in the German-speaking world. In 1954 he took over the Neurological Department of the Geriatric Hospital of Vienna in Lainz, where he remained until his retirement in 1975. International acclaim followed his breakthrough with the clinical application of L-DOPA in Parkinson's disease. Birkmayer, as a strong adherent to the scientific interpretation of neurological and psychiatric disease, has encouraged multidisciplinary research. This is reflected in his establishment of the former Ludwig Boltzmann- Institute of Neurochemistry, in which pharmacological, biochemical and histopathological research into neuropsychiatric diseases was performed under one roof. Further to his initial work on L-DOPA, Birkmayer has been in the forefront of supplementary parkinsonian therapy using enzyme inhibitors: benserazide in 1967, unselective monoamine oxidase inhibitors in 1962 and deprenyl in 1975.

More than 150 years have passed since involvement of the nervous system in leukemia was first reported by BURNS, while the possibility of the primary brain tumor derived from the lymphoreticular tissue was recognized much later. BAILEY in 1929 described such neoplasms under the term perithelial sarcoma. Later these tumors of the nervous system have been variously designated as "Perivascular of perithelial sarcomas, reticulum cell sarcomas or microgliomas," as controversy has evolved and still exists on the definition of this group of neoplasms and on the nature of their cells of origin. Much of the unfortunate confusion concerning the neoplastic lesions attributed to "microglia" and other derivations of the RE system arose because their close relationship to extra neural cells has been ignored. On the other hand, communication in the field of malignant lymphomas has become increasingly difficult because of the termino logic maze and conceptual diversities of traditional morphological classifica tions that have limited valid comparisons. Although at present we are still far from a precise recognition of the basic features of lymphoproliferative processes and from a fairly general agreement on the terminology of non-Hodgkin lymphomas, there is encouraging evidence recently of some enlightment on the nature of tumor cells that provides the basis for a reasonable and generally acceptable lymphoma classification."