Fibrils and reticulum of connective tissue, amyloid, mucin and connective-tissue hyalin are blue; nuclei, protoplasm, fibroglia fibres, axis cylinders, neuroglia fibres and fibrin are red; elastic fibres are pink or yellow; red blood-cells and myelin-sheaths are yellow. 2. =Mall’s Method for Reticulum.= 1. Digest frozen sections of fresh tissue for 24 hours in a solution of Parke, Davis and Co.’s pancreatin 5 grms., soda bicarbonate 10 grms., water 100 cc. 2. Wash carefully in water. 3. Place section in test-tube half-full of water and shake thoroughly to remove cells. 4. Spread out on slide and allow to dry. 5. Allow a few drops of the following solution to dry on slide:—picric acid 10 grms., absolute alcohol 33 cc., water 300 cc. 6. Stain for 30 minutes in the following mixture: acid fuchsin 10 grms., absolute alcohol 33 cc., water 66 cc. 7. Wash in the picric acid solution for a second. 8. Dehydrate in absolute alcohol; xylol; balsam. 3. =Unna’s Method for Collagen.= 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. 3. Wash in water for 5 seconds. 4. Differentiate in 0.25 per cent aqueous potassium permanganate solution 10-20 seconds. 5. Wash in water for 5 seconds. 6. Dehydrate in alcohol; clear in xylol or origanum; mount in balsam. Fibroglia fibrils and cell-nuclei intensely red; contractile elements of striped muscle, smooth muscle, neuroglia fibres, cuticular surfaces of epithelial cells and fibrin are also red; connective-tissue fibres brownish-yellow or colorless; elastic fibres, unless degenerated, bright yellow. _b._ =Elastic Fibres.= Weigert’s method is so superior to the Unna orcein-stain that it alone is given here. It is our best elective stain: gives permanent preparations, and is in every way practical. The stain keeps well. Weigert’s Method for Staining Elastic Fibres.