Abstract
The ability of influenza virus to cause hemagglutination was strongly inhibited by a factor in egg-white. The EW factor was found to be as much as 200 times as inhibitory as rabbit serum. The hemag-glutinative ability of an aged formolin or heated virus was 750 to 1000 times more inhibited by EW than that for a fresh virus culture. The EW factor gave an interfacial precipitation reaction with concentrated virus suspensions and both the precipitating and inhibiting capacities were destroyed by treatment with dilute periodate.