In order to demonstrate the genesis of mutants in vitro, conditions were chosen under which a strong increase occurs in the number of necrotic lesions caused by the mutants on Java tobacco. Owing to this increase, the number of mutants multiplies 20 times over the original value in an area where the infectivity has decreased by only one half. This precludes selective processes. Nor may the rise be attributed to a higher degree of probability of the mutants assertiveness due to dilution or inactivation, as frequently noted Mundry 1957 a. Therefore the mutants were induced by treatment with nitrite.
Trans. of Zeitschrift fuer Vererbungslehre (West Germany) v89 p614-630 1958.