ROTATION TECHNIQUE IN ELECTRON MICROSCOPY OF VIRUSES.

Some of the features revealed by the rotation technique of examining electron micrographs may be artifacts. To avoid misinterpretation, "rotated" photographs should be compared with originals. The criterion of reinforcement of structures in the "rotated" photographs is not enough, and it cannot be presumed that all the structures reinforced are actually present in the object under study. Further tests for radial symmetry in the arrangement of elements in a pattern should be made.