Sixteen cases of acute anterior poliomyelitis in young fit adults are described. The differential diagnosis is discussed, taking into consideration cases of other diseases whom I have had under my care. The relative value of various symptoms and signs is discussed. Conclusions are drawn as to the value of signs with regard to immediate prognosis. The use of penicillin in the treatment of twelve cases is described. In these cases, penicillin was of no value. Sodium penicillin, when injected intrathecally, was not devoid of irritant effects.