The specimen is a slice of the left lung. The upper lobe is relatively normal, except for an old scar near the apex of the lung caused by tuberculosis. The major abnormality is that the lower lobe is uniformly consolidated (airless and solid) due to lobar pneumonia, with inflammatory cells and exuded plasma filling the airspaces. The shaggy material on the pleural surface is fibrin, a protein derived from fibrinogen in exuded plasma.