III. METHOD FOR DETECTING POLIOMYELITIC VIRUS IN SEWAGE AND STOOLS.

1. The active agent in sewage and aqueous suspensions of human stools, capable of producing poliomyelitis in rhesus monkeys after intraperitoneal inoculation, can be precipitated by 50 per cent saturation with ammonium sulfate, and no loss of activity seems to occur during this procedure. 2. The precipitated virus is not consistently "redissolvable" in water. 3. By precipitation and subsequent dialysis of the precipitate, a preparation is obtained which may be smaller in volume, and is less toxic for monkeys, than was the original material. 4. The procedure can be applied in tests on the infectivity of stools, and sewage specimens.