The bacteriological and physical studies to be described were made in the Dudley Road Hospital during the winter 1958-1959 while investigating an outbreak of epidemic bronchiolitis in infants. It was found that the role of mucus in this respiratory disease was of significance; plugs of mucoid material were demonstrated in bronchioles, and bronchopneumonia was a frequent concomitant. As yet, very few studies of respiratory tract mucus have been made. Müller1 investigated the mucus ground substance in sputum, and Brogan2 carried out chemical analyses on pooled mucus; apart from these studies, the subject is poorly documented.
With this in mind, it was decided to investigate various environmental factors affecting mucus: variations in consistency and physical state due to the action of pathogenic bacteria and polymorphs, the relation between consistency and water content, and still further properties which might prove relevant in assessing the significance of mucus in respiratory disease