Studies on the Pathogenesis of Meningitis. I. Intrathecal Infection*

Meningitis was produced in dogs by inoculation with 10/sup 3/10/sup 6/ type III pneumococci via the subarachnoid space. This produced an infection lasting 48-96 hrs and characterized by cerebrospinal fluid (CSF) changes, including an increase of leukocytes and bacteria and a decrease in glucose concentration. This concentration was inversely related to the cell and bacteria counts of CSF. Pretreatment for 5 dogs with prednisolone did not alter the course of infection. When leukopenia was produced by 450 r whole-body irradiation, the number of inflammatory cells in the CSF was reduced in infected animals and survival was prolonged. This indicates that exudation into the subarachnoid space may have a harmful effect on the ventricular cavities where it may cause hydrocephalus. (H.H.D.)