During the summer of 1936 we had an opportunity to study an epidemic of acute conjunctivitis in a boys' camp. The clinical appearance of the patients and the results of routine smears of material from the conjunctivas suggested that a pneumococcus was the causative organism. Cultural studies, however, resulted in the isolation of Streptococcus viridans from the inflamed conjunctivas. In view of the rarity with which this micro-organism has been thought to be of etiologic significance in conjunctivitis, it was considered worth while to report the observations made during this epidemic.
Relatively little importance has been given to Str. viridans as a normal inhabitant of the conjunctival sac or as a causative agent of acute conjunctivitis. In the older literature, moreover, this type of organism has often been referred to by the all-inclusive term "streptococcus," with little or no attempt to differentiate between hemolytic, green and indifferent species.