vii SPORE STAINING 31 



Ziehl's fuchsine : 5 per cent aqueous solution of carbolic 



acid 100 cc. 



Concentrated alcoholic solution of 

 fuchsine 11 cc. 



All these solutions must be filtered before use. 



First Method. 



(a) Prepare a film in the usual manner and pass it three 

 times through the flame. 



(5) Filter some of the fuchsine solution into a small 

 evaporating dish and gently warm it, keeping it just 

 steaming. 



(c) Float the cover-glass, film surface downwards, on the 

 warm stain and continue gentle warming for twenty to 

 thirty minutes. 



(d) Now wash the specimen in water. 



(e) Dip it for a few seconds in the acid alcohol, and at 

 once wash it again in water to remove the acid. 



(/) Examine it in water, under a high power, for spores, 

 which should appear as round or oval red bodies, the 

 bacilli themselves being faintly pink or unstained. 



If the spores are unstained or too much decolourised, 

 place the film back in the fuchsine solution, and 

 decolourise for a shorter time in the acid alcohol. 



If, on the other hand, the bacilli are not sufficiently 

 decolourised, dip the cover-glass once more into 

 the acid alcohol. 



(g) When the spores are well stained, and the bacilli 

 practically unstained, dry the specimen with blotting-paper 

 and pass it three times through the flame. 



