NEW METHODS OF USING THK ANILINE DYES. 401 



Some New Methods of Using the Aniline Dyes 

 for Staining Bacteria. 



By 



K. Hanbury Hankln. 



I HAVE lately been staining bacteria in tissues for Dr. Klein 

 by some new methods that seem to offer certain advantages 

 over those already in use. 



Dr. Klein has kindly supplied me with tissues containing 

 various bacteria. But most of my results have been obtained 

 with Bacillus anthracis. 



In the methods about to be described the hardening of the 

 tissue that generally precedes section cutting must be care- 

 fully attended to. It is always necessary to use Miiller's 

 fluid. The tissues must be cut into very small pieces, and the 

 liquid frequently changed. If this is not done the nuclei will 

 be found to show more afl&nity for the dye than the bacteria, 

 and only those organisms that are placed near the margin of 

 each section will be visible. 



Nearly equally good results are obtained with perfectly 

 fresh material. 



Method A. Materials required : 



(1) A strong watery solution of methyl blue or Weigert's 

 aniline oil solution of the same dye. 



(2) A saturated alcoholic solution of eosin. This should 

 be made simply by shaking up the dye with the alcohol and 

 filtering. By heating the alcohol or letting the solid eosin 

 remain for some days in contact with the liquid a stronger 

 solution is obtained, which is undesirable for the present 

 purpose. 



