Submicroscopic Morphology of Avian Neoplasms I. Studies on Erythroblastosis. ∗

Summary

Ultrathin sections of tumorous spleen and liver from chickens of the so-called line 15 with erythroblastosis have been examined in the electron microscope. In cells of these organs spherical or spheroid structures were observed, composed of a central dense core of about 260 A, surrounded by a less dense material and limited by an outer membrane, varying in diameter from 570 Å to 760 Å. The structure of these particles resembles that of particles described in other tumors of chickens and in other tumors of known viral origin. No particles of similar character were observed in cells of organs from control healthy chickens.