Abstract
1. Conditions are described under which the three types of live or formalin-inactivated poliomyelitis viruses can be concentrated 10–100 times in good yield, with elimination of approximately 90% of the extraneous protein normally present in poliovaccines.2. It was shown that 0·1–0·2 mg./ml. AlPO4almost quantitatively adsorbed the antigens, provided the adsorptions were carried out at a pH round about 5. Re-elution of the antigens occurred readily at pH 7–pH 8.3. No noticeable conversion of the ‘D-antigen’ to the ‘C-antigen’ occurred during the concentration.