Not much is known of the factors which determine the growth, regeneration and health of the nasal epithelium. Such knowledge, when once obtained, will axiomatically be of first importance, not alone in the treatment of nasal infections but in the prevention and the early abortion of many air-borne diseases. If means were at hand to hasten the regeneration of epithelium after some organism has succeeded in breaking through it, secondary invasion might be effectively restricted.
Three facts, only relatively recently established, have stimulated us in an attempt to learn more about the characteristics of growth of the nasal and the sinal mucosa: (1) that after complete removal the mucosa of a sinus can be regenerated with normally functioning ciliated columnar epithelium;1 (2) that in clinical practice this regeneration is not invariable, and (3) that normal vigorous ciliary activity usually— in fact, almost invariably—exists within a sinus even in the presence