The paper which follows gives the results of a study of a small outbreak of poliomyelitis occurring between Sept. 15 and Oct. 1, 1916, in a large apartment house, occupied by thirty families, situated in the outskirts of a large city. Wickman1 pointed out that the outbreaks of poliomyelitis in the small Swedish villages were the most fruitful sources of knowledge concerning the mode of transmission of the disease. The outbreak of poliomyelitis in the X house seemed to offer in a similar way an exceptional opportunity for study, for the children in it formed a small community of their own, fairly well isolated from the rest of the city.
The outbreak of poliomyelitis at the X house is, however, interesting apart from the standpoint of its epidemiology; for of the 8, possibly 10, children affected, all but 2 escaped paralysis; several furnished unusually good indications of the incubation period