Abstract
A comparative study of the biochemical reactions given by cultures of Enterobacter aerogenes and by members of the "Hafnia group" is reported. It is concluded that sufficient differences of taxonomic importance between the two warrant elevation of latter "group" from subspecies to species level. Further, it is shown that the correct name for the bacteria formerly called the "Hafnia group" or Enterobacter aerogenes subsp. alvei is Enterobacter hafniae(Moeller) Ewing.