338 APPLICATION OF METHODS OF BACTERIOLOGY 



tures it will be found on microscopic examination to present 

 an arrangement somewhat like a chain of beads. (Fig. 68.) 



Determine its peculiarities and describe them accurately. 

 They should be as follows: 



Upon microscopic examination a micrococcus should be 

 found, but differing in its arrangement from those just 

 described. The single cells are not scattered irregularly or 

 arranged in clumps similar to bunches of grapes, but are 

 joined together in chains like strands of beads. These' 

 strands are sometimes regular in the arrangement and size 

 of the individual cells composing them, but more commonly 



Fig. 68 



Streptococcus pyogenes. 



certain irregular groups may be seen in them. Here they 

 appear as if two or three cells had fused together to form a 

 link in the chain, so to speak, that is somewhat longer than 

 the others; again, portions of the chain may be thinner than 

 the rest, or it may appear broken or ragged. Commonly the 

 individuals comprising this chain of cocci are not round, 

 but appear flattened on the sides adjacent to one another. 

 The chains are sometimes short, consisting of but four to 

 six cells; or, again, they may be much longer, and extend 

 from a half to two-thirds the way across the field of the 

 microscope. 



