202 BACTERIOLOGY 



from similar micrococci which occur in the rnethra by their 

 being invariably decolorised by Gram's method, although 

 otherwise they take the aniline stains very readily. 



If it is wished to demonstrate the gonococci in fresh 

 gonorrhceal secretion, the following is the best mode of 

 procedure : A drop of the pus is placed upon a cover-glass 

 and spread out lightly, so that the glass is covered with a 

 thin cloudy film ; but the common method of laying two 

 cover-glasses one over the other and then drawing them 

 asunder must not be employed here. The cover-glass is 



now stame( i with a con- 

 centrated alcoholic solu- 

 tion of methyl blue, 

 rinsed in water, dried, 

 and mounted in Canada 

 balsam. 



Neisser has recom- 

 mended the following 

 method of double stain- 

 ing : The cover - glass 

 preparations are brought 



FIG. 78.-GoN'ococci FROM THE UKETHRAL for S0me HlinuteS illto 



a warm concentrated 



alcoholic solution of eosine, the superfluous dye is then 

 soaked up with blotting-paper, the preparations laid for a 

 quarter of a minute in concentrated alcoholic solution of 

 methyl blue, and rinsed in water. 



Schiitz's method consists in preparing a filtered satu- 

 rated solution of methyl blue in 5 per cent, aqueous carbolic 

 acid, in which the preparations are stained for five to ten 

 minutes in the cold. After rinsing in water they are laid for 

 an instant in very dilute acetic acid, again rinsed in water, 

 and double- stained in very dilute solution of safranine. 

 The gonococci are blue and the pus-cells salmon-coloured. 



