The present work deals with the question of the heredity of intracranial tumours, the twin method constituting hereby the basis for investigation.
1. In an unselected series of twins collected from the Psychiatric and Neurological Clinic of the university of Münster (Psychiatrische und Nervenklinik der Universität Münster) in the case of seven examined pairs of twins (3 monozygotic, 4 dizygotic: like sex and unlike sex) manifestation of cerebral tumours is dissimilar (table II).
2. This unselected series combined with previous casuistic reports published until now in world literature (table I) of twins with cerebral tumours has not yet brought a sufficient basis for definite genetic conclusion. The question of inheritance in cerebral tumours will only be elucidated by procuring and reviewing material from a larger unselected series of twin patients afflicted with cerebral tumours.