Fig. 5. Hematoxylin and eosin–stained histology of pig trachea after 4 h of intubation. ( A ) Image demonstrates intact epithelial layer at 2 cm distal to the larynx. Magnification ×100. ( B ) Image of epithelium and lumen enlarged from area indicated in A . Demonstrates presence of polymorphonuclear cells in epithelium and in the mucous in tracheal lumen. Magnification ×1,000.