Morphology of the Development of Type B Virus Particles in a Transplantable Mammary Tumor of ICR/Ha Mice

Summary

The electron microscopic appearance of virus particles is described in ICR/Ha mammary tumors and a sequence of development is suggested in which small particles become enveloped by a double-membraned structure to form a 6-ringed structure not before described. The possible sequence of events leading to the formation of walls of large sacs from the outermost membrane is traced through a diagram and counterpart electron microscope photographs.