Errare humanum est

In the erratum published in the issue of 13 February (p. 656), Tables 1 and 2 from the report "Mutagenicity of fly ash particles in Paramecium" by J. Smith-Sonneborn et al. (9 Jan., p. 180) were printed incorrectly. Significance lines missing in the original tables were also missing in the erratum. With determination, we again reprint the tables as they should have appeared (Table 1 above, Table 2 at right).