152 BACTERIOLOGY. 



from them. They are then brought for one minute into 

 a dilute watery solution of eosin or safraniri, or Bismarck- 

 brown ; again washed out for a few seconds in alcohol, 

 and finally for one-fourth minute in absolute alcohol. 

 From this they are transferred to xylol for a half- 

 minute. The remaining steps in the process are the 

 same as those given in the general method. In some 

 cases better results are obtained by reversing the steps 

 in the process and staining the bacteria last, for then 

 the frequent decolorizing action of the alcohol on the 

 bacteria is diminished; thus, place the sections from 

 alcohol into eosin, safranin or Bismarck-brown for a few 

 minutes, then wash out in 50 per cent, alcohol, then for 

 from three to five minutes in the dilute aniline-water 

 gentian -violet solution, then into the iodine bath, after 

 three minutes wash out in alcohol, and, finally, for one- 

 fourth minute in absolute alcohol, and then into the 

 xylol, from which they may be mounted. The organ- 

 isms which may be stained by this method are mic. 

 tetragenus, b. diphtherise, b. anthracis, staph, pyogenes 

 aureus, and a few others. It cannot be successfully 

 employed with the bacillus of typhoid fever. 



Staining with dahlia and decolorizing with soda solu- 

 ■ tion. Another method that is not very commonly em- 

 ployed, though the results obtained by its use are in 

 many cases very satisfactory, is to stain the tissues in a 

 strong watery solution of dahlia (about one-fourth satu- 

 rated) for from ten to fifteen minutes ; from this they 

 are brought into a 2 per cent, solution of sodium or 

 potassium carbonate, and from this into alcohol, alter- 

 nating from the one to the other, until the .section is 

 almost colorless. From the alcohol they are rinsed out 

 in water and then brought into a dilute watery solution 



