Spores are the resting forms of various organisms and are stained with difficulty, but when once stained are hard to decolorize.

Abbott's Method

1. Stain the cover-glass deeply with methylene-blue, heating until the solution boils.

2. Wash in water.

3. Wash in 95 per cent, alcohol, containing 0.2 to 0.3 per cent. HC1.

4. Wash in water.

5. Stain for eight to ten seconds in anilin-fuchsin solution.

6. Wash in water, dry, and mount.

The spores are stained blue; the bodies of the bacteria, red.

MöLler's Method

1. Wash the cover-glass for two minutes in chloroform.

2. Wash in water.

3. Place in a 5 per cent, watery solution of chromic acid for one-half to two minutes.

4. Wash in water.

5. Stain with carbolfuchsin for one minute, heating the solution slowly until it boils.

6. Thoroughly decolorize in a 5 per cent, solution of sulphuric acid.

7. Wash in water.

8. Stain in aqueous methylene-blue (1 gm. to 100 c.c.) for thirty seconds.

9. Wash in water, dry, and mount. The spores will be red; the bacteria, blue.

The most satisfactory spore-staining method is really the negative staining of the spore obtained when a bacterial preparation is stained by dilute carbolfuchsin or Löffler's methylene-blue. The spore appears as a highly refractile piece of glass in a colored frame. The acid-fast method, as for tubercle bacilli, gives good results, but the decolorizing must be lightly done, otherwise the spore will lose its red stain.