THE FOLLOWING data concern unpublished work done in 1965. We have been stimulated to document now our observations as they provide further evidence (Stewart et al, 19671) that support the belief that the herpes-type virus of the cultured Burkitt's tumor cells (Epstein et al, 1964, and 19652,3 and Stewart et al, 19654,5) has biological activity.
The data concerning our agent are given below. In brief, after intracerebral inoculation into Macaca mulatta babies there resulted a devastating malacic and liquefying panencephalitis which is indistinguishable from human herpetic encephalitis. The observation raised many issues.
Necrotizing encephalitis caused by herpes simplex virus in human beings, particularly in babies, is well known (see Pette, 19586 and Blackwood et al 19637). Because of descriptive detail, and because of the great similarity of the lesions to those in our monkeys, reference is necessary to Young et al, 19658 who