Kaolin adsorbs inhibitory activity more rapidly than total nitrogen from crude egg-white and less rapidly than total nitrogen from semipurified inhibitor preparations. The adsorption of inhibitoris reversible. Treatment of semipurified preparations with active swine influenza virus causes a slight increase in the adsorption of activity and total nitrogen. Active virus combines with inhibitor-coated kaolin in the cold and can be recovered in great part at room temperature. A smaller amount of virus is bound by untreated kaolin. Heating the virus for 30 minutes at 53°C increases its adsortion by kaolin.