Derived [N/Fe] abundances for M 2 stars in Table 4 as a function of the [C/Fe] abundances from our sample (filled circles). A C vs. N anticorrelation is apparent. For comparison we also plotted our previous results on a sample of MS and SGB stars in the cluster NGC 1851 (white dots). The red dashed line indicates the relationship, shown over its full range, that prevails in NGC 1851 from our earlier work.