48 BACTERIOLOGY FOR NURSES 



Flagella Stain. Van Ermengen's Method. Three solutions 

 are necessary : 



(1) Twenty per cent tannic acid solution .... 60 c.c. 



Two per cent osmic acid solution 30 c.c. 



Glacial acetic acid 4 to 5 drops 



The fixed film is placed in this solution for one hour at room 

 temperature or for five minutes at 100 C. It is then washed 

 in water and afterwards in absolute alcohol, followed by immersion 

 for one to three seconds in 



(2) Silver nitrate 3 to 5 per cent solution. Without washing the slide 

 is transferred to 



(3) Gallic acid 5 gm. 



Tannic acid 3 gm. 



Fused potassium acetate ......... 10 gm. 



Distilled water 350 c.c. 



The slide should be moved gently to and fro in this solution for a 

 few minutes, then returned to the silver nitrate until the film turns 

 black. It is then thoroughly washed in water and dried. 



The staining of flagella is one of the most difficult of bacteriologi- 

 cal procedures. In order to get good results the slide must be 

 scrupulously clean, the film should be made from a young ten to 

 eighteen hour agar culture and should be spread as carefully and 

 with as little manipulation as possible. 



Indian Ink Method for the Examination of Spirochetes. - 

 An emulsion of good quality Indian ink is sterilized by steaming 

 and allowed to settle for a few days. One drop of the sediment 

 and one drop of water are thoroughly mixed with a loopful of the 

 material to be examined on a clean slide. The film is dried in the 

 air and examined with the oil immersion lens. If spirochetes 

 are present they stand out unstained surrounded by the dark 

 Indian ink. 



Wright's Stain. This is one of several modifications of the 

 polychrome Romanowsky stains used chiefly for staining animal 

 cells and also for bacteria that stain faintly by ordinary methods. 

 It can be purchased ready for use or it may be prepared as follows : 

 1 per cent methylene blue and 0.5 per cent sodium carbonate are 



