1. No difference in susceptibility to infection between splenectomized and non-splenectomized monkeys was observed when virus was injected intravenously in large amounts.
2. In a small series of animals, the results suggested that splenectomy decreased resistance to amounts of virus subinfective for non-splenectomized monkeys.
3. Splenectomy subsequent to intravenous or intrasplenic inoculation of amounts of virus subinfective for non-splenectomized monkeys did not render the animals susceptible.
4. Following vascular injection, the virus accumulates in the spleen, where it can be detected 24 hours after inoculation, but not at 3 or 5 days.
5. Evidence that splenectomy interferes with antibody formation is presented and discussed.
6. We were unable to demonstrate virus in crude extracts of poliomyelitic spleens but were successful with perfused spleen extracts. This may be due to removal of a neutralizing factor.
7. Attempts to immunize test animals with virus present in poliomyelitic spleens were negative.