On the Inoculation of the HST (Hamazaki) Virus Isolated From Yoshida Tumor on Emb-ryonated Eggs

HST virus which was isolated in 1950 from the roshida ascites tumor by Hamazaki and his associates is a pantropic virus which creates a unique inflammatory granulation in mice. When virus of an acute infections disease was inoculated on embryonated eggs, not only the egg membrane but also the chick embryo were infected more or less, and when the number of virus increased the chick embryo died, terminating the development of the egg. However, the tumor inducing virus which represents the Rous virus does not cause heavy disturbances in the embryo and it is well known that chick hatched from this egg can long maintain health unless it is subjected to a provocative factor. HST virus is no exception to this example and though it is inoculated on an embryonated egg it does not cause any serious disturbance on the embryo. The tissue changes of the chorio allantois infected by the "Virus were the focal proliferation and necrosis of ectodermal epithelium, the proliferation of the mesenchymal cells of the mesodermal layer adjacent to these foci, accompaning infiltration of lymphoid cells and leukocytes with edema, especially eosinophilic leukocytes. By these tissue changes a terrace-shaped thickening of the membrane was the result. In the viscera of the chick embryo a special change in the liver was seen, i. e., along the edge of the liver greyish white nodules submacroscopic to miliary in size appeared. The principal pathologic change of the foci is the coagulation necrosis of the liver parenchyma and only a slight infiltration about the periphery of the foci was observed. Moreover, proliferation of mesenchymal cells occurred next to the walls of the large blood vessels of the liver (principally, the portal veins) and with the added infiltration of a small number of lymphoid cells and leukocytes sharply defined nodular foci were formed. Though this was a rare instnace, similar pathologic changes were seen also in the walls of the blood vessels of the cerebrum stem of the embryo and along the periphery local gliosis was observed.