A Note on the Gram Stain

Abstract

A modification of the Gram stain in which iodine-alcohol is substituted for 95% alcohol as a decolorizing agent has been found particularly useful in staining Gram-positive organisms in tissues and also for smears. The technic for tissue sections follows:

1. Apply nuclear stain.

2. Wash.

3. Stain in Hucker's gentian violet 2 to 3 minutes (i. e. 1 part Sat. Alc. Sol. crystal violet to 4 parts 1% Aqu. Sol. ammonium oxalte).

4. Wash in water.

5. Stain in Gram's iodine 5 minutes.

6. Wash in water.

7. Decolorize in 95% alcohol to which enough tincture of iodine has been added to give a mahogany color.

8. Counterstain.

9. Dehydrate and mount.