Between 1870 and 1884, as both a medical student and a member of the faculty, Sir William Osler performed approximately 1000 postmortem examinations at McGill University in Montreal. He conducted 786 of these examinations during his 7 years (1877--1884) of service as a pathologist at the Montreal General Hospital. The results of these were carefully recorded and catalogued either by him or by those who compiled the Pathological Report of the Hospital. Included in this material are many early descriptions of neurosurgical disease. Osler used this information for subsequent teaching in both Philadelphia and Baltimore. Osler's early and lifelong special interest in diseases of the nervous system not only led him to make seminal observations but also served to initiate his influence and relationships with the emerging leaders in neurology and neurosurgery.