A Study of the Ia and Oa Strains of the Shope Fibroma Virus with Special Reference to the Berry Transformation

Abstract

Studies were made of the survival of the IA and OA strains of the Shope fibroma virus on the chorioallantoic membranes of developing chick embryos. Although both strains survived for a period of 8-15 days in case of passage on the membrane, they apparently did not multiply. At no time was the IA virus detected in the organs of the embryo although it was detected on the chorioallantoic membrane 8 days after inoculation. An attempt to produce the Berry "trans-formation" phenomenon on both the chorioallantoic membranes of developing chick embryos and rabbits was made. It was not successful on the egg membrane but occurred in 7 of the 20 rabbits used. The Belgian hares showed a greater number of positive results.