[Induction of brain tumors with methylnitrosourea. Comparative study of 2 strains of rats]

For clarifying the question with respect to the different incidence in various animal strains of the formation of cerebral tumours 10 BD II and Wistar rats were given methyl-nitrosourea (a weekly amount of 5 mg per kg of life-weight over a period of 35 weeks). After an average of 398 and 367 days half the number of animals in each group showed cerebral tumours. These primarily seem to be isomorphous gliomas which then show an increase in malignity.