WE HAVE selected 143 cases from the records of the Montreal Neurological Institute for analysis of the relation of spontaneous subarachnoid hemorrhage,1 intracerebral hemorrhage, and intracranial aneurysm. These cases cover a period of 10 years, from 1938 to 1948. The criteria for selection were as follows: The material is classified as follows: The data are discussed under three headings: (1) general systemic and local meningeal reactions to blood in the subarachnoid space; (2) statistical considerations and points of interest in the three conditions (subarachnoid hemorrhage, intracerebral hemorrhage, and intracranial aneurysms); (3) treatment. GENERAL SYSTEMIC AND LOCAL MENINGEAL REACTIONS General Systemic Reactions. —The presence of fever and polymorphonuclear leucocytosis of the blood is almost the rule. Patients have sometimes been admitted