Human amylase has been shown to be an effective and powerful inhibitor of the gonococcus in vitro. Its action appears to be on the bacterial cell wall. When tested in osmotically stabilised liquid media the organism was not inhibited; however the organisms which grew in such cultures appeared to be cell wall variants, which were less sensitive to penicillin than the parent strains. Studies on these variants suggest that they are "transitional-phase variants." Since cervical mucus has much in common with an alkaline osmotically stabilised liquid medium and also contains a high concentration of amylase, it seems possible that these variants may occur in vivo.