ABSTRACT
A concentration of 250 mg m-3 lincomycin was administered by aerosol to 40 chickens, weighing between 1900 and 2200 g. The birds were killed in groups of five at different intervals after dosing, and the trachea, lungs and blood serum were examined for antibiotic content by bioassay. The antibiotic was present at high levels in the trachea for one to 24 hours, and significant levels were present in the lungs and serum. Respiratory macrophages were obtained from the lungs and air sacs of the chickens by lavaging through the surgically prepared trachea with a paediatric urinary catheter. The macrophages were identified by morphology as round or slightly amorphous, refractile, frequently grannular cells; they phagocytosed Staphylococcus aureus 6538.