LESSON in LOFFLER'S METHYLENE-BLUE 13 



Concentrated alcoholic solution of methylene-blue, 



3 vols. 

 Caustic potash solution 1 : 10,000, 10 vols. 



A convenient method of staining is to keep the staining 

 solution in a wide-necked glass-stoppered pot, and to hold 

 the film in the staining solution with a pair of forceps, 

 gently moving it about for one or two minutes. Then 

 transfer it to water and wash off the superfluous stain. 



(2) Staphylococcus pyogenes aureus : liquefying gelatine 

 culture. 



(a) With a loop remove a little of the liquefied gelatine 

 and spread it carefully over a clean cover-glass. 



(b) Allow the film to dry in the air, and then pass it 

 three times through the flame. 



(c) Eemove the gelatine by means of acetic acid in the 

 usual manner, or by floating the film on warm water for 

 five to ten minutes. 



(d) Stain with Loffler's methylene-blue, wash in water, 

 dry with blotting-paper, and mount in Canada balsam. 



Examine with -^ in. oil immersion. 



(3) Torula alba : non-liquefying gelatine streak culture. 



Proceed in exactly the same manner as in the case of 

 Bacillus prodigiosus (vide p. 12). 



Stain with aqueous gentian-violet or aqueous fuchsine 

 solution or with Loffler's methylene-blue. 



Examine with -fy in. oil immersion. 



Examination of Moulds 



Aspergillus niger : potato culture. 



