The administration of cortisone to chicken embryos infected with influenza B virus results in (a) an initial inhibition of viral synthesis and (b) an eventual increase in the final yield of virus attained. Increased yields of virus are attained regardless of the number of viral particles in the infecting inoculum or the proportion of particles which are infective.

Changes in the distribution ratios of allantoic fluid and intramembrane virus are effected by cortisone only as the secondary result of reduction in viral synthesis.

The manifest effect of cortisone on influenza A virus increase is inhibitory unless inocula containing relatively high proportions of inactive viral particles are used.

This content is only available as a PDF.