TAXONOMY 225 



handle permits the placing of the forceps on the table while the cul- 

 ture material is obtained. 



3. Place several drops of distilled water on the cover slip and add a 

 loop full of the organism secured from the pure culture in a test tube 

 as follows: 



4. Remove the cotton plug by the third and fourth fingers of the 

 left hand. 



5. Hold the open test tube between the thumb and forefinger of the 

 left hand. 



6. By means of a previously flamed platinum needle, remove a 

 little of the culture from the surface of the culture media. 



7. Replace the cotton plug. 



8. Add the culture media to the drop of distilled water on the 

 cover slip and distribute this material by stirring. 



9. Evaporate the water on the cover slip to dry ness by holding it 

 some distance above the Bunsen flame and slowly enough to prevent 

 connection circles being formed by the material affixed to the cover. 



10. Pass the cover glass three times through the Bunsen flame. 



11. Apply the stain, which should remain long enough to stain the 

 objects. 



12. Wash off the stain with distilled water. 



13. Dry the cover glass above the flame. 



14. Apply a drop of balsam, turn the cover slip over and drop it on 

 to the center of a glass slide previously provided and cleaned for this 

 purpose. 



Gram's Method. This is a method of differential bleaching after 

 a stain. The cover glass preparations or sections are passed from 

 absolute alcohol into Ehrlich's anilin gentian violet, where they 

 remain one to three minutes, except tubercle bacilli preparations 

 which remain commonly twelve to twenty-four hours. They are 

 then placed for one to three minutes (occasionally five minutes) in 

 iodine potassium iodide water (iodine crystals i, potass, iodide 2, 

 water 300), with or without washing lightly in alcohol. In this 

 they remain one to three minutes. They are then placed in absolute 

 alcohol until sufficiently bleached, after which they are cleared in 

 clove oil and mounted in balsam. 



Certain organisms, when stained by this method give up the stain 



