1. An account on the experiment dealing with the "yellow tobaco mosaic" or " tomato aucuba mosaic " of tomato is given. 2. The symptoms of the virus disease under consideration are identical with those shown by tomato aucuba mosaic, and its various properties in general coincide with Nicotiana virus 1 C. 3. Datura stramonium, Nicotiana glutinosa and N. sanderae produce primary local lesions on the inoculated leaves ; and many other solanaceous plants form yellow mottlings on the new leaves. 4. The virus is very resistant to high temperature and chemicals, and retainjits infectivity for more than a year when kept in test tubes.