sentences:  His career-long interest in the manner of transmission of the influenza virus was first stirred by the great epidemic of 1932–33, the year in which he entered general practice.It culminated in a book, published in 1992 that questioned the theory of person-to-person transmission being enough to explain the simultaneous appearance of influenza in places far apart.His initial hypothesis proposed that the cause of influenza epidemics during winter may be connected to a seasonal influence.