Micro Mounts, Reverse and Converse

Abstract

Very young normal mice, injected intracere-brally with a virus obtained from mice showing flaccid paralysis of the hind legs, died without paralysis. Some adults showed no reaction. The percentages of mortality and of successful artificial infection increased with the decrease in age. The virus passed with ease through Berkefeld filters. No evidence of relationship with the virus of human poliomyelitis was obtained. Lesions were noted only in the nervous system.