Nebulae and abundances in galaxies.

Some current problems related to abundances in H II regions are briefly reviewed. For H II regions with measured electron temperatures, the discrepancy in O/H between the sun and the Orion Nebula is stressed. Studies of abundance and temperature variations within H II regions in NGC 604 are summarized. These studies are yielding data on those line ratios which are sufficiently constant to be used as parameters characterizing an H II region as a whole and as potential abundance indicators. Attempts to model low-excitation H II regions are reviewed, and it is concluded that abundances in such regions will be obtained by such modelling in the near future.