SECTION SEVEN 



4. Decolorize by adding Solution D drop by drop for about 

 ten seconds, until hardly any more colour comes out: this takes 

 about ten seconds. 



5. Dry in air and counterstain in Solution E for five to ten 

 seconds. 



6. Wash in tap water, dry and examine. 



Results: 



Gram-positive organisms, blue. Gram-negative, red. 



GRAM'S IODINE - ANILINE GENTIAN VIOLET 

 For spirochaetae of Vincent's Angina and for Trep, pallidum 



Solutions required: 



A. N/20HCI. 



B. Gram's iodine. 



C. Aniline gentian violet. 



Technique: 



1. Spread scrapings from ulcer on a slide; then allow to dry 

 in the air before fixing by heat in the usual manner. 



2. Immerse in N/20 HCl for 10 seconds. 



3. Wash in running water for 5 seconds. 



4. Immerse in Gram's iodine for 5-10 seconds. 



5. Wash with water. 



6. Stain with aniline gentian violet for 5-10 seconds. 



7. Wash with water. 



8. Drain and blot dry. 



9. Mount if desired, in D.P.X., Clearmount, or Emexel and 

 examine under the oil immersion objective. 



Results: 



Spirochaetes are stained deep violet. 



eference: Bailey, H. D. (1937-38), J. Lab. and Clin. Med., 23, 960. 



