Abstract
Studies have been made of the effect of ectromelia virus upon the Ehrlich mouse ascites tumor. It was found that the virus multiplied in the tumor cells. In the course of this work the appearance of two types of cytoplasmic inclusion bodies were recognized as it was the case with monocytes. In smears the first type stained azurophilic (A-inclusion) and the other type pale bluish (B-inclusion). From the view-point of morphological criteria with aid of the histological observation and electron microscopy of ultrathin sectioning specimens made at various intervals after virus inoculation, the azurophilic inclusions, appearing in the early stage, appear to coincide with DNA positive matrices which are synthetized by infected cells themselves and contain some developmental viruses. At the next stage, the second type (B-inclusion) appeared in a close relation with the azurophilic inclusion. The latter was classified in about 4 types by their internal structures which varied from one extreme of superficial attachment of viruses to another extreme of internal filling with viruses. The author discussed the mechanism of ectromelia virus multiplication through the formation of inclusion within the Ehrlich ascites tumor cell.
