I. Design of Experiment, Mortality, and Findings in Lung Parenchyma

Abstract

Tracheostomy was performed on 97 male beagles. All but eight (group N) were trained to smoke cigarettes over the first 56 days through tubing from a cigarette holder to the tracheostoma.Of the 89 smoking dogs, two died and one was withdrawn during this period. On day 57, the remaining 86 dogs were divided into four groups assigned to various smoking categories, some smoking filler-tip and others nonfilter cigarettes-Starting on day 876, all surviving dogs were killed and lung sections were examined microscopicallyw The lungs of the group N dogs were normal while histopathological changes were found in aU smoking dogs. Grealest changes were in the lungs of dogs smoking nonfilter cigarettes most heavily.