In a period of nine weeks, four private duty nurses at a municipal hospital developed viral hepatitis. As a result of the deaths of the first two of these, a state of near-panic developed among the employee population. A program of inoculation of personnel was instituted during which 1,900 employees received γ-globulin. A survey of 1,300 employees by means of serum glutamic pyruvic transaminase screening together with more intensive evaluation of those with abnormal levels proved useless in disclosing subclinical cases. Concepts of transmission of this disease are reviewed, including more recent studies which suggest the existence of a fecal-oral route in the spread of serum hepatitis.