The subject of this paper is not new, but it has not been given adequate attention, and because of its importance merits extensive study. Heimbeck1 in Norway, Ross2 in Canada, Shipman and Davis,3 and Whitney4 in this country have sensed the problem and have suggested corrective measures that are satisfactory only in part, because none of these writers has sought to prevent contagion, which in my experience is the essence of the question. Furthermore, as this inquiry progressed it appeared to me that this might be a study that would throw more light on the pathogenesis of tuberculosis.
The present investigation was undertaken because there seemed to be an unusually high incidence of tuberculosis among student nurses at the Ancker Hospital in St. Paul. This institution is the city and county hospital for St. Paul and Ramsey County. It has 975 beds, 215 of which are