

o 



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PRACTICAL BACTERIOLOGY 



the incubator or with a spirit lamp or Bunsen burner, 

 ' but only till vapour arises? 



3. Decolorizing processes have the effect of decolorizing the 



nuclei and rendering them obscure ; to prevent this, stain 

 the sections first with lithio- or picro-carmine. (See 

 Giinther's modification of the Gram method, 38). 



4. To reduce or prevent the bleaching effects of alcohol during 



decolorization, add to the alcohol a small quantity of 

 the stain with which the section was treated in the first 

 place. 



5. In clarifying sections do not use clove oil for anilin dyes 



(except in the Cladius method), as it has the power of 

 removing the stain. L^se oil of cedar, and best of all for 

 bacteria is xylol. 



XXXVII. METHODS OF STAINING BACTERIA IN 

 SECTIONS OF ORGANS AND TISSUES. 



/ WEIGERT'S ORIGINAL METHOD. 



1. Remove the section out of alcohol into water, or directly 

 into the stain one-half to one minute. 



2. Into stain ' methylene blue ' one to two minutes. 



3. Wash the section in water. 



4. Into one-half per cent, solution of acetic acid in water for 

 one minute. 



5. Into absolute alcohol thirty seconds, spreading the section 

 well out. 



6. Again in absolute alcohol thirty seconds. 



7. Into xylol thirty seconds. 



8. Place on a slide, dry with filter-paper, and mount in xylol 

 jbalsam. 



Anthrax bacilli can be detected in sections by this method, 

 as also many of the bacteria belonging to the Septicsemise 

 Haemorrhagicae group of organisms, but care must be used not 

 to carry the acid and alcohol treatment too far. The Glanders 

 bacilli can also be demonstrated in sections of tissue with this stain. 



XXXVIII. THE GRAM-GUNTHER METHOD FOR 

 SECTIONS. 



1. Remove the sections into water for two or three minutes. 



2. Into a solution of picro-carmine two to five minutes. 



