Beet yellows virus

[Letter] Several plant viruses have been found to occur as elongated particles of variable length and 10–15 mµ in width. Leyon has published electron micrographs showing such rod-like particles with a width of about 10 mµ in sap from plants infected with beet yellows virus and in the specific precipitates produced by mixing the sap with its antiserum. We have also found rods in these two kinds of preparation. They do not occur in sap from healthy beet plants, and by analogy with other viruses which have been purified it could readily be assumed that the rods are the virus particles themselves. There are, however, other factors which make this assumption less tenable and suggest that the rods are not the only anomalous component in sap from infected plants.