Since the introduction of leucotomy by Lima and Moniz in 1936 numerous authors have reported their experiences with this form of treatment in mental disorders (Freeman and Watts, Fleming, Mayer-Gross, Hemphill et al.). Although leucotomy has stood the test of time well, and all workers agree that in selected cases its application is well justified, so that it has become an established form of treatment, there are many obscure clinical aspects which require elucidation. It is obvious that the collection of observations from as many angles as possible is necessary in order to further research in this promising field. It is hoped that a report on the results of leucotomies performed in this Hospital will be a contribution to that end.