Lung Clearance of Particles and Bacteria

The ability of the lung to clear particles and viable bacteria was studied in guinea pigs exposed to cigarette smoke. The animals were given ten puffs of fresh cigarette smoke from one to four cigarettes daily during one to four weeks. They were then exposed to a mixed aerosol of killed radioactive and viable Escherichia coli. The clearance of radioactive and viable bacteria was determined—the former being an indicator of the mucus clearance and the latter, of the phagocytic activity of the lung. Smoke from cigarettes of high and medium tar content was found to decrease both mechanical and bactericidal clearance. After shorter exposure times, the results indicate that the mechanical clearance flow is affected earlier than the bactericidal clearance. When phenylmethyloxadiazole was added to the tobacco by 2% by weight, an effect on the mechanical or bactericidal clearance could not be demonstrated.