A Staining Method for Corynebacterium diphtheriae.

The following method is recommended for the staining of Corynebacterium diphtheriae. It provides a good contrast between the body of the organism and the granules in it. Cover the fixed and dried film with Loeffler's methylene blue, leave for five minutes, wash with water, decolorize rapidly with 1/1000 sulfuric acid. The acid should not stay on the film for more than a few seconds, wash with water, treat rapidly with Gram's iodine, wash again and counterstain with 1 per cent aqueous solution of eosine for half a minute, wash with water and dry. The body of the organism takes a pinkish color, the granules a blue black one. The contrast is quite clear. While more complex than the methods used in routine diagnostic laboratories, this method produces slides which are very clear and satisfactory for classroom demonstration.