The MEF, strain of poliomyelitis virus has been adapted to suckling mice by giving each animal 2 intracerebral injections (each 0.02 mI) separated by 2-3 hours. Passages were carried out at 4-day intervals. By the 17th passage 100% of mice injected became paralysed on or before the 4th day after inoculation and by the 29th passage 100% were paralysed on the 2nd day. The virus reaches the maximum concentration in the brain and cord immediately before the onset of paralysis and persists for 2 days after the onset. The extent of the paralysis is not related to the concentration of the virus in the central nervous system. The strain adapted to suckling mice has been found to cause paralysis after intraperitoneal inoculation into 3-14 day-old mice.
It has been reported that subdmal effusions are common in certain types of meningitis. Two case histories of infants, in whom attacks of pneumococcal meningitis were complicated by subdural effusions, are presented. The technique of subdural taps is discussed briefly.