Summary.1Two types of yeasts,A, round cells,B, oval cells, were isolated from a “blown” tin of sweetened condensed milk.2Both types were able to reproduce similar “blowing” when inoculated into tins of sweetened condensed milk.3The oval type was considerably more rapid and vigorous in its action than the round, but was less resistant to heat and drying.4These yeasts are compared with those isolated by Pethybridge from Irish, by Hammer from American, and by Knudsen from Danish and Dutch, sweetened condens