More than 1500 strains of aerobic cutaneous diphtheroids were characterised by morphological, biochemical, and nutritional tests. From the results of nine tests—lipophilic character, lipolytic ability, production of porphyrin, reduction of nitrate, and ability to decompose glucose, maltose, sucrose, fructose, and galactose—these strains could be divided into 15 groups: seven for the fluorescent strains and eight for the non-fluorescent strains. Distribution of the groups over the body surface varied, non-fluorescent group-I strains being particularly common in the nostrils.