BACTERIOLOGICAL TECHNIQUE 23 



3. Heat in the flame until vapour arises. 



4. Wash in water. 



5. Dry with filter paper. 



6. Mount in xylol balsam. 



XVII. KNACK'S METHOD OF STAINING GONOCOCCI 

 IN COVER-GLASS SPECIMENS. 



1. Make the cover-glass from the pus in the ordinary manner, air 

 dry, and fix. 



2. Stain with methylene blue. 



3. Place the cover-glass in a 1 per cent, solution of argonin four 

 minutes. 



4. Wash and dry the specimen. 



5. Place the cover-glass in a watery solution of fuchsin 1-20 for ten 

 seconds. 



6. Wash, dry, and mount in xylol balsam. 



XVIII. NEISSEITS METHOD FOR THE DIFFERENTIAL 

 DIAGNOSIS OF DIPHTHERIA BACILLI IN COVER- 

 GLASS SPECIMENS. 



1. Cover-glass specimens are prepared from cultures grown on 

 Loffler's blood serum, at 34 and 35, not exceeding 36 C. ; the 

 cultures must also not be younger than nine and not over twenty to 

 twenty-four hours' 1 old ; air dry, and fix the specimen in the flame. 



2. Stain three seconds with Neisser's No. 1 solution (see Stains, 

 58). 



3. Wash the specimen with water. 



4. Stain three to five seconds with Neisser's No. 2 solution pre- 

 viously filtered (see Stains, 58). 



5. Wash in water, dry, and mount in xylol balsam. 



Result. The body of the Diphtheria bacillus is stained brown, con- 

 taining blue granules as a rule two one at each end, or only one at 

 one end, seldom any in the middle. The granules are oval, and never 

 found free. In other organisms resembling the Diphtheria bacillus, 

 these are round, and always situated at the end, close to one another. 



XIX. UNNA'S METHOD OF STAINING FUNGI. 



Solution A. Concentrated watery solution of methylene blue. 



B. Unna's glycerine-ether mixture. 



1. Place the suspected material (crusts, etc.) on a slide, and saturate 

 with acetic acid. 



