The Morgan Bacillus

Abstract

Many of the type culture strains labelled with the name of Morgan bacillus do not agree in significant cultural characters with the generally accepted criteria for this group. When widely variant strains are eliminated a certain residue of fairly uniform strains is left. Even among these there is far from being as close a correspondence as that between the strains of Salmonella enteritidis or of the Sonne type of dysentery bacillus. Antigenic uniformity is lacking. Freshly isolated fecal strains with "Morgan bacillus" characteristics have, in the authors'' experience, been isolated only from persons suffering from some form of gastro-intestinal derangement. The cultural and antigenic characters of Morgan bacilli seem to relate them nearly to Bact. coli. They may be reasonably regarded as an ill-defined division of the large and variable group conveniently known as Bact. metacoli. They possess perhaps somewhat greater pathogenic power for man than the "slow lactose fer-menters" or true Bact. coli strains.