Fig. 2.

Histology of the thymus of N. forsteri. (a, b) Paraffin-embedded cross-sections of thymus stained with haematoxylin/eosin. The thymus is demarcated into a cortex (C) and medulla (M) and delimited by a capsule (Cap in a). Note the presence of myoid cells in the medulla, and the cortico-medullary boundary (arrow heads in b). Giant multinuclear cell is indicated by an arrow in b) and blood vessels by an asterix in (a) and (b). (c, d) LR white-embedded semi-thin sections of thymus stained with methylene blue showing trabeculae (arrows heads in c) originating from the capsule (Cap). Cortical reticular epithelial cells are indicated by an asterix. In (d), REC form a meshwork with their cytoplasmic processes in the cortex (C) and medulla (M). (e, f) Paraffin-embedded cross-section of thymus stained with PAS/Alcian blue. Note the Alcian blue positively stained material in the medulla (M) interstitium and the cytoplasm of foamy cells (* in e). Cells stained positively with PAS are indicated by arrowheads. (f) Tissue section treated with salivary amylase as a control. Cortex (C). Thymic blood vessels (*).