Eric French contributed greatly to the early Australian studies on Newcastle disease virus, producing the foundations on which subsequent Australian studies were based. In 1964 he conducted the first major serological survey for Newcastle disease in the Australian poultry flock, and showed that the pathotypes of the virus recognised at that time were not present. After the isolation of strain V4 in 1966, he initiated some of the first studies on the nature of this stain. In particular, he demonstrated the avirulence of this virus, its ability to infect chickens when delivered orally with food and its potential utility as a vaccine. Subsequent studies by other workers included the development of strain V4 as a conventional vaccine and as a vaccine suitable for use in village chickens.