The propagation of variola virus on the chlorioallantoic membrane of embryonated eggs was first reported by Torres and Teixeira (1935). Application of this finding was made by Lazarus et al. (1937), Buddingh (1938) and Markham and Bozalis (1939) who utilized embryonated eggs as a diagnostic medium. Nelson (1940, 1943), described the development and stability of variola virus in egg passage but ...

An assay capable of recovering individual viable rodent cells localized in various organs of the chick embryo is described. This assay is based on the differential sensitivity of chick and rodent cells to the cytotoxic drug ouabain. Utilizing this assay, the potential of the chick embryo as a model system for studying metastasis was examined. Several cell lines were characterized in three ways:...