TECHNICAL APPENDIX. 177 



(spread upon a spatula of German silver or glass) to 

 Loffler's alkaline methyl blue solution for from five to 

 thirty minutes, and is then placed for a few seconds 

 in one-per-cent acetic acid. After the differentiation 

 the section is placed in absolute alcohol, xylol, and 

 Canada balsam. We must try how long the acetic 

 acid may be allowed to act, and must accelerate the 

 dehydration in alcohol as much as possible; the 

 bacilli should be blackish-blue, the nuclei blue, the 

 protoplasm bluish. 



2. Nicolle states that by the following method he 

 has obtained very good section staining of objects 

 which are stained with difficulty for example, in 

 glanders, typhoid fever, etc. : 



Loffler's blue, one to three minutes. 



Washing in water. 



Treatment with ten-per-cent solution of tannin for 

 a few seconds. 



Washing in water. 



Absolute alcohol, oil of cloves, xylol, Caoada 

 balsam. 



3. According to Gram : 



(1) Ehrlich's solution, three minutes. 



(2) Iodine-potassium iodide solution, two minutes. 



(3) Alcohol, one-half minute. 



(4) Alcohol containing three per cent hydrochloric 

 acid, ten seconds. 



(5) Alcohol, several minutes until maximum decol- 

 orization. 



(6) Xylol; finally mounting in Canada balsam. 



If the tissues are to be stained in a contrasting 

 color, the section is placed, after the maximum de- 

 colorization with alcohol, in a watery solution 



