MODIFICATION OF LOEFFLER'S FLAGELLA STAIN 183 



No. 1 



Commercial formalin (40 per cent formaldehyde) 1 



Distilled water 1 



No. 2 



Chromic acid (5 per cent, aqueous solution) 2 



Acetic acid (10 per cent aqueous solution) 1 



As soon as the cover-glass preparation, made as described 

 later, has dried in the air, the cover-glass is flooded with either 

 of these solutions, and after a minute and a half or two minutes 

 it is washed off with water. Although I have had good results 

 with both of these solutions, I have found that the mordant used 

 by me is sufficient without previously using a special fixative 

 so that it simplifies the process to dispense entirely with any 

 fixing solutions. 



It was my aim besides doing away with the heating of mordants 

 and stains, so that the entire process is performed at room tem- 

 peratures, to use only those solutions which will keep well, so as 

 to avoid making them up freshly every time. 



One of the first requisites for success in flagella staining is to 

 have cover-glasses which are absolutely clean and free from 

 every trace of oil or grease. I have found that they may be 

 satisfactorily cleaned in the following manner: I drop them, 

 one at a time, into a small stender dish containing a solution 

 prepared as follows: 



parts 



Water 1000 



Potassium bichromate 60 



Sulphuric acid (commercial) 60 



After allowing the cover-glasses to stand in this cleaning solu- 

 tion for ten minutes, or longer, the solution is washed out by 

 running clear tap water into the dish until every trace of color 

 has disappeared. I then pour off the water and cover the cover- 

 glasses with 95 per cent alcohol, using about 20 to 25 cc. of alcohol, 

 and add about 15 drops of concentrated ammonium hydroxide. 

 A few minutes later the cover-glasses are picked out, one at a 

 time, with a pair of forceps, and dried carefully by wiping them 

 with lens paper. It is best to use only one side of the paper, 



