Topically administered cocaine 20%, in a single application, temporarily paralyzed the cilia, and the consequently reduced traction apparently held mucus in the acini and effected a temporary lag in mucus excretion. Three successive applications caused acute acinar depletion and ciliary paralysis.

Hexylcaine chloride 5% immediately desquamated all intranasal epithelia, damaged the proximal portion of the acini, and induced acinar exhaustion and mucosal inflammation—effects not overcome within 5 days.

Internal dehydration produced progressively viscous mucus, severe acinar gaping with mucus anchored in the acini, a heavy surface sheet, and deceleration or arrest of mucociliary flow.

Avitaminosis A induced reduction in the height (about 50%) of all mucosae and acini, especially the inner lining of the maxillary concha, caused an actual 50% reduction in the number of cells per acinus, and retarded the mucociliary flow rate about 50%

Pilocarpine induced initial hypersecretion, later exhaustion, and, still later, slow production of densely staining mucus in the acinar cells; also acinar gaping.

Breeding in a germfree environment produced a greatly reduced mucosal depth throughout the nasal fossa, an extraordinary reduction in the number of cells per acinus, relative reduction in the number of acinar neck cells, and concomitant increase in ciliated cells in that region.

Exposure to a temperature of –20°C for 1 hr caused blanching of all secretory cells, acinar gaping, and temporary reduction of mucosal depth.