During the course of research on the growth of virus-free plants by culturing apical meristems removed from infected plants (D. G. A. Walkey & J. Fitzpatrick, in preparation), it was necessary to determine whether the virus was present in the meristems before they were cultured. This was normally done by direct inoculation to test plants, but because of the small size of the tips the possibility was examined of making direct observations on them using the electron microscope. The results are reported herein.