Abstract
Organ cultures of rat trachea inoculated with either a type b or a non-capsulated strain of Haemophilus influenzae showed loss of ciliary activity and disruption of the mucosal surface. Examination of tissue pieces by scanning electronmicroscopy showed that mucosal damage was due to the sloughing of epithelial cells. Bacteria associated with the epithelial surface were seen infrequently and this, together with the observation that sloughed cells were usually free of adherent bacteria, indicated that bacterial attachment was not a necessary prerequisite for the production of tissue damage.