The Authers isolated the virus from young chiken group with nervous symptom in north district of kyushu, 1965 and investigated the certain biochemical properties of isolated virus. Several results of the experiments were obtained as follows: 1) Isolated virus multiplied, showing cytopathogenic effect in cultures of chikcken kidny and chick embryo cell, However, in puppy kidney and calf kidney cell culture neither multiplicyties and cytopathogenicity of the virus was observed. Inclusion bodies could be found by dyeing samples. 2) On primary isolation, cytopathogenic changes were observed from three days after inoculation. On the subsequent passges, cytopathogenic changes occurred usually within 48 hours, and the after several passages. ....