In some cases of intracranial tumor epileptiform convulsions occur, and in other cases this symptom is entirely absent. Tumors involving the brain do not produce a clearcut sequence of cause and effect as seen in other pathologic processes. The symptoms and signs produced by tumor are extremely variable, inconstant to a marked degree and altogether inconsistent. Nevertheless, when approached with due caution and reserve, the problem is fascinating in spite of its bewildering inconsistencies.
From the records of patients who had come to the Mayo Clinic from Jan. 1, 1919, to Nov. 1, 1929, 313 cases of intracranial tumor were found in which complete clinical studies had been made and necropsy data had been assembled. It may be assumed that the group is fairly representative of the incidence of intracranial tumor in the general population. The criticism might be made that only cases in which death had occurred were taken;