That the conjunctivitis of infants designated as inclusion biennorrhea is transmissible to the adult was first demonstrated by Wolfrum when he inoculated successfully 2 volunteers inducing what he considered to be trachoma. The diagnosis, however, based partially on the presence of inclusion bodies in the experimental disease and partially on his conviction of their specificity in trachoma, was not justified by the clinical manifestations. Gebb, on the other hand, also reporting successful transmission, concluded the condition resulting from the inoculation was not trachoma. There the matter remained until recently when Thygeson reported the results of his elaborately conducted and carefully controlled experiments in which material from infants with inclusion blennorrhea transferred to adults initiated not trachoma but swimming-bath conjunctivitis. During the course of experiments on inclusion blennorrhea in this laboratory, the opportunity was afforded to study the progress of an accidental transmission of this disease to an adult. While irrigating the eyes of an infant 11 days old, on the fifth day of suspected gonococcal conjunctivitis, some of the exudate was discharged into the left eye of the attending nurse. Despite immediate and vigorous lavage, a mild conjunctivitis was obvious on the following morning, when Dr. A. C. Lange was consulted. Because of the diagnosis in the case of the infant, optochine was prescribed, and on the fifth day the first appearance of small scattered follicles suggested a mistaken diagnosis in the case of the infant. Scrape smears of the conjunctiva stained by Wright or Gram showed neither inclusion bodies nor gonococci. On the sixth day, smears were repeated and numerous inclusions were found, but not gonococci. Smears made on the same day (11th) of the infant's conjunctiva likewise revealed inclusions without gonococci, thus justifying the diagnosis of inclusion blennorrhea.