Abstract
It has been reported that the two strains of mouse encephalomyelitis virus named GD VII and FA, respectively, accidentally discovered by Theiler and Gard (1) during experiments with yellow fever, have been shown to be immunologically related to each other. However, the differences in the biological properties, except hemagglutinating activities, between two viruses have not yet been demonstrated.In the hemagglutination, there is the evidence that the GD VII virus agglutinate human 0 type red cells at 4°C in saline (2), whereas the FA virus is unable to agglutinate human 0 type cells at 4°C in saline, but is capable of hemagglutinating chicken cells at 4.. in 1. 5% CaCl2 (3).In the present paper, some properties of the viruses, for instance, heat, ether and acetone stabilities which have not been reported are demonstrated.