Abstract
Chiba sarcoma, a strain of the viral sarcoma of the chicken, produced in the chicken thymus by injection in loco of the causal agent, was studied by electron microscopy.
In some of the tumor cells examined 6 or 7 days after the injection some structures were seen containing a various number of virus particles and comparable to the gray bodies of Bonar et al. These structures were observed at all possible stages of their development-as mere gray bodies and as complicatedly indented spaces filled with virus particles, to mention their earliest and ultimate forms. The virus is likely to enter the gray body of the tumor cell by phagocytosis multiply within the body and, finally, to be discharged from the cell.
