The house census in the City of Boston and the preparation of this monograph were made possible by the financial assistance of the Metropolitan Life Insurance Company. This organization has devoted a considerable sum of money to the study of influenza in its various phases.

The author is indebted to his chief, Dr. Milton J. Rosenau, for helpful advice and criticism and for the inspiration to carry on this investigation. Dr. W. H. Frost has made many valuable suggestions. Appreciation is also due Mr. Edwin M. Knights, who is responsible for all of the charts, and to Mrs. V. K. Davis, who aided in the tabulation of results of the Boston investigation.

The house-to-house census was carried out with the co-operation and assistance of the Federated Jewish Charities in Boston and individual members of the social service departments of the Massachusetts General Hospital and the Peter Bent Brigham Hospital.

The Author.

Department of Preventive Medicine and Hygiene,

Harvard Medical School, Boston,

September 17, 1920.

This monograph is one of a series of studies carried out under the supervision of the Influenza Commission of the Metropolitan Life Insurance Company. The Influenza Commission is investigating the etiology and prevention of the acute respiratory diseases, and the work is being carried on in Boston, New York City, Chicago, and Washington. The members of the Commission are Dr. M. J. Rosenau, Chairman, Dr. G. W. McCoy, Dr. L. K. Frankel, Dr. A. S. Knight, Dr. E. O. Jordan, Dr. W. H. Frost and Dr. W. H. Park, Secretary.

INFLUENZA.