90 APPLIED BACTERIOLOGY 



with Liiffler's methylene blue for three minutes, washed in 

 water, blotted, dried, and mounted. Examined with a 

 rV inch oil immersion lens, the bacilli will be found to be 

 stained blue and the spores red. 



This method gives very satisfactory and pretty prepara- 

 tions. The spores of Bacillus megatherium and Bacillus 

 filamentosus are more easily stained than those of Bacillus 

 anthracis or the hay bacillus {Bacillus subtilis). 



Fiocca's Method. — This method is also very successful and 

 rapid. About 1 c.c. of a saturated alcoholic solution of 

 fuchsine is added to 20 c.c. of a 10 per cent, ammonia 

 solution contained in a dish. The solution is heated until 

 steam just commences to rise. The prepared cover-glasses 

 are then immersed in the solution for from three to ten 

 minutes, removed to a 20 per cent, solution of sulphuric acid 

 to decolourise, washed in water, and finally counter-stained, 

 as in the method given above. 



Staining of Flagella. — The flagella or organs of motion 

 which are attached to many bacilli and to some micrococci 

 are much more difficult to demonstrate by staining than 

 spores. In order to reveal the presence of these delicate, 

 whip-like processes, it is necessary to have recourse to a 

 complicated and ingenious method of staining, as they 

 cannot be stained by any of the methods already described, 

 as the flagella do not possess any affinity for dyes unless 

 they are previously prepared with a ' mordant,' or a fixing 

 material to enable the flagella to subsequently fix the dye. 

 The following points must be carefully attended to in order 

 to obtain satisfactory results : The cover-glasses must be 

 absolutely clean, in which case a drop of water will spread 

 itself evenly over the surface, and will not run back or 

 refuse to adhere to any portion of it. The smallest particle 

 of grease or dirt will absolutely prevent any satisfactory 

 result being arrived at. No trace of nutrient medium should 



