ENCEPHALOMYELITIS OF MICE : III. EPIDEMIOLOGY.

1. In the feces of approximately two-thirds of normal mice 6 weeks of age an agent in all respects similar to the virus of mouse encephalomyelitis can be recovered. 2. In isolated mice, fed on sterile food and water, excretion of virus has been shown to persist up to 53 days after isolation. 3. In normal mice known to be virus carriers virus has been demonstrated in the gastro-intestinal tract but not in the central nervous system, thoracic or abdominal viscera, or any organs of the head. 4. The source of the virus excreted in the feces has been shown to be located in all probability in the intestinal wall. 5. Evidence is presented that the virus can invade the animal organism, as virus has been demonstrated in the mesenteric lymph glands.