Fig. 13From: Harderian gland of flying and non-flying birds: morphological, histological, and histochemical studiesLight micrograph of the HG of duck (A, B), goose (C, D), ibis (E, F), and pigeon (G, H). Positive reaction in centrally located cells of ducts and the glandular epithelium of secretory units with alcian blue. Stain, alcian blue pH 2.5Back to article page