STAINING OF BACTERIA IN TISSUES. 147 



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 alcoiiol into 

 picro-carmine for one-half hour, 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 abso- 

 lute alcohol, and then into the xylol, from which they 

 may be mounted. The organisms 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 two 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 

 of either eosin, Bismarck-brown, or safranin for one 

 minute, then washed out in alcohol, finally into absolute 

 alcohol, and then into xylol, from which they may be 

 mounted in the manner given. 



