Combinations of rubin and orange (Delépine) and erythrosin and picric acid (Powell White) are also advised as differential combination stains, but are not so useful as Van Gieson’s. Other combination methods are to be found in the various modifications of the Ehrlich triple stain.
CHAPTER XXVI.
SPECIAL STAINING METHODS FOR DEMONSTRATION OF PATHOLOGIC CONDITIONS IN CELLS OR TISSUES.
I. AMYLOID. The best selective staining of amyloid is obtained with relatively fresh tissues; long preservation in alcohol or formol tends to weaken the reactions. Probably the best effects are obtained by formol-fixation for 24 hours, and sectioning on the freezing-microtome. Good results may be produced, however, after any of the ordinary fixing and hardening methods by cutting the sections on the freezing-microtome, without imbedding, or imbedding in paraffin. The metachromatic reactions are not satisfactory with celloidin sections. With hæmatoxylin and eosin the amyloid substance stains a light red or bluish-pink; Van Gieson’s stains it a yellow or brownish-pink color, giving it practically the same color that it does epithelial hyalin. The different tissue-relations of the two substances serve to distinguish them. The most important specific amyloid stains are:—
1. Iodine.
1. Stain in Lugol’s solution 5-10 minutes.
2. Dehydrate in absolute alcohol 4 parts, tincture of iodine 1 part.
3. Clear and mount in origanum oil. Seal preparation with paraffin, gold size or shellac.
The iodine reaction is also applied to fresh tissues by pouring Lugol’s solution over a freshly cut surface, and is a good gross test for amyloid. In both microscopic and macroscopic preparations iodine gives a mahogany brown color to amyloid; other tissue is yellow. The iodine reaction may be intensified by placing the sections in a 1 per cent sulphuric acid; the brown color may be changed to blue, violet or green.
2. Methyl Violet.
1. Stain in 0.5 per cent methyl-violet solution ½ to several minutes. Examine in water.