The Action of Hexamethylenetetramine on Members of the Colon and Aerogenes Groups.

The presence of members of the aerogenes (Aerobacter) group of bacteria offers considerable interference in the positive identification of the members of the colon (Escherichia) group in waters. Many attempts have been made by research workers to find selective media by which the members of the above-mentioned groups might be differentiated. One of the most recent selective media for such a differentiation has been proposed by Wilson (1933), who used a broth containing hexamethylenetetramine (urotropin). This author claims that urotropin medium has the power of inhibiting strains of the Aerobacter group and, at the same time, of allowing the growth of the members of the Escherichia group. The following quotation from the publication of Wilson is of interest: