Correspondence arising. Symposium of Microbial Metabolism and the Carbon Cyle, University of Minnesota, 13-16 July 1986. Evans spoke on 'Degradative metabolism of aromatic compounds in anaerobic environments'. The Proceedings were published in Microbial Metabolism and the Carbon Cycle, ed. S Hagedorn, R Hanson and D A Kunz (NY, 1988). 1986