STAINING OF SPORES. 13 



Staining of Spores. 



Potato cultures of Bacillus anthracis and Bacillus 

 lactis viscosus are supplied. (B. megatherium, B. sub- 

 tilis or B. filamentosus might be employed.) 



(a) Prepare thin cover glass films of these bacteria 

 in the usual manner, dry and fix in the flame. 



(6) Float in Ziehl's carbol-fuchsin, or in anilin water 

 fuchsin, for 20 to 30 minutes, keeping the staining fluid 

 warm. 



(c) Wash the films in water and rinse for two to 

 three seconds in acid alcohol. (Alcohol 97 cc, Hydro- 

 chloric acid 3 cc.) At this stage the specimen may be 

 examined by mounting in a drop of water. The acid 

 decolorizes the rods, leaving the spores stained. If the 

 bodies of the bacilli are still red, the film must be again 

 washed through the acid alcohol. If the spores are not 

 stained place the film again in the carbol-fuchsin. 



(d) If the spores are properly stained, place the film 

 for one to two minutes in Loeffler's methylene blue to 

 stain the rods. 



(e) Wash in water, dry thoroughly and mount in 

 Canada balsam. 



The spores are stained red, rods blue. 



