Every experiment with the contents of one, or with those pooled from two to five of the normal stock of Rockefeller Institute strain of albino mice, 1 to 2 months of age, revealed the presence of a virus which, after intracerebral inoculation into normal mice, induced characteristic paralytic encephalomyelitis, indistinguishable from Theilerapos;s disease. No difference was seen in this effect of intestinal contents deriving from animals paralyzed during the course of spontaneous encephalomyelitis and from normal mice. The influence of age on carriage of virus, as well as on the persistence of the carrier state, is discussed.
The present, as well as previous work has shown that the virus found in normal (or paralyzed) mice is similar to that of Theiler's disease in all of its properties thus far investigated; among the strains of the latter now at hand it can be classified with those having a low degree of invasiveness after peripheral inoculation.
The virus has thus far been recovered from intestinal contents, intestinal walls, and mesenteric glands but not from the central nervous system of normal mice; from these sites, as well as from the central nervous system, in paralyzed mice. In order of concentration of virus, the contents have more, the walls less, and the glands least.