ON AIR-BORNE INFECTION^*: STUDY II. DROPLETS AND DROPLET NUCLEI.

^* In 1931 an instrument for the bacterial examination of air was developed by the Department of Public Health Administration of the Harvard School of Public Health. The application of this instrument in the present studies has been made possible through the facilities and assistance of several Departments of Harvard University. The technical assistance of Mr. Stone, graduate student in the Department of Sanitary Engineering of the Harvard Engineering School, the use of the experimental chamber of the Department of Industrial Hygiene of the School of Public Health and the advice and cooperation of the Departments of Bacteriology and Preventive Medicine of the Harvard Medical School are here gratefully acknowledged.