xvi CHEMIOTAXIS 77 



(d) Carefully inoculate this drop from a fresh broth 

 culture of Bacillus anthracis, using a small platinum loop 

 and avoiding over-inoculation. 



(e) Place the cover-glass, drop downwards, on the moist 

 ring of filter-paper. 



Examine with a high power, or ^ in. oil immersion, 

 using a narrow diaphragm. 



Choose a good field for observation, one containing a 

 short chain of bacilli and numerous cells. 



Note that the coarsely granular cells attack the bacilli 

 first, and that the phagocytes become active later. 



Eventually take off the cover-glass, carefully allow 

 the film to dry, and stain it with cosine and 

 methylene-blue in the usual manner. 



Examine it with ^ in. oil immersion, and note 

 especially the relation of the eosinophile cells and 

 phagocytes to the bacilli. 



Chemiotaxis 



(a) Inject a small quantity of an old broth culture of 

 Bacillus pyocyaneus under the skin of the thigh of a pithed 

 frog. 



(&) Four hours later remove some of the lymph and 

 prepare films. 



(c) Stain these in the usual manner with cosine and 

 methylene-blue. 



Examine with a high power and -^ in. oil immersion. 

 Note the large number of eosinophile cells attracted 

 (" positive chemiotaxis "). 



