EXPERIMENTS WITH THE VIRUS OF POLIOMYELITIS.

1. Efforts to adapt the virus of poliomyelitis to the rabbit organism and to produce poliomyelitis in rabbits by testicular injection and by brain injection after testicular passage produced no evidence that the virus could be adapted in this manner. Suggestive symptoms produced in very young rabbits were duplicated in non-specifically treated and in uninoculated controls. The admixture of a vaccine virus, adapted to the rabbit organism, with the poliomyelitis virus in similar injections and passages did not aid the adaptation. The virus of poliomyelitis did not survive 24 hours in the rabbit testicle-whether alone or mixed with vaccine virus. Repeated intraperitoneal and intradermal injection of poliomyelitis virus and of poliomyelitis and vaccinia virus mixtures produced no disease in rabbits. Massive doses of concentrated virus by stomach tube in conjunction with meningeal irritation produced no symptoms in rabbits. 2. No neutralizing substances against poliomyelitis virus could be produced in rabbits by the repeated intraperitoneal and intradermal injection of poliomyelitis virus or of poliomyelitis-vaccinia virus mixtures. 3. Although attempts to infect monkeys by intrastomachic injections, after bile irritation of the mucosa, were entirely negative, evidence was obtained that repeated intrastomachic injection after bile irritation may produce an appreciable degree of immunity. 4. No evidence could be obtained that the cellular elements of the blood contain the virus in any greater proportion than the whole blood. 5. One attempt to immunize by neutral virus-serum mixtures was entirely negative.