142 PRACTICAL BACTERIOLOGY. 



poles : The hacillus pyocyaneus, the spirillum Met- 

 schnihofii, the cheese spirillum [spirillum tyrogenwm), 

 the spirillum cholerce asiaticce, the spirillum Finhleri, 

 etc. 



The following have numerous polar flagella : The 

 spirillum undala, spirillum rubrum, spirillum concen- 

 tricum, and also numerous other species of spirilla 

 found in marshy or stagnant water. The micrococcus 

 agilis has also several flagella, which possibly originate 

 at one point. 



The flagella of the blue milk bacillus are the most 

 easily demonstrated j the mordant in this case may be 

 used alone without the addition, of either acid or alka- 

 line solution ; but the flagella are also stained, if on 

 the one hand twenty drops of acid, or on the other 

 fifteen drops of caustic soda, are added to the mor- 

 dant. The staining is most successful if from eight 

 to ten drops of acid are added. With this bacillus it 

 is not so important to prepare the mordant quite 

 accurately ; with many other species, however, this is 

 not the case. For example, in dealing with the typhoid 

 bacillus, great exactitude is required, exactly 22 drops 

 or 1 ccm. of the sodium solution must be added to 

 the mordant, one drop more or less is suflBcient to 

 prevent the flagella from becoming stained. In order 

 to determine tlie exact quantity of acid or alkali which 

 it is necessary to add for different species, experiments 

 must be made in each case ; according to LoflBer the 



