1. Harden in absolute alcohol; imbed; cut.

2. Stain 5-15 minutes in polychrome methylene-blue.

3. Wash in water.

4. Differentiate in 1 per cent neutral orcein in absolute alcohol, 15 minutes.

5. Dehydrate in absolute alcohol.

6. Clear in xylol; mount in balsam.

Nuclei dark blue; protoplasm light blue; collagen dark red; plasma-cell granules greenish-blue; mast-cell granules red.

4. Mallory’s Fibroglia Method.

1. Fix thin, small, fresh pieces of tissue in Zenker’s fluid; harden in alcohol; imbed in celloidin or paraffin; cut.

2. Stain sections in 1 per cent aqueous acid fuchsin for 12 hours in the cold, or 20-30 minutes at 50-56°C.