THE STREPTOCOCCUS PYOGENES. 253 



be found, but differing in its arrangement from the 

 staphylococci 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 com- 

 posing them, but more commonly certain irregular parts 

 may be seen in them. Here they appear as if two or 



Fig. 55. 



Streptococcus pyogenes. 



three cells had fused together to form a link, so to speak, 

 in the chain, that is somewhat longer than the remain- 

 ing links; again, portions of the chain may be thinner 

 than the rest, or may appear broken or ragged. Com- 

 monly 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, con- 

 sisting of four to six cells, or again they may be much 

 longer, and extend from a half to two-thirds of the way 

 across the field of the microscope. 



Under artificial conditions it sometimes grows well, 

 and can be cultivated through many generations, while 

 again it rapidly loses its vitality. When isolated from 

 the diseased area upon artificial media it seems to retain 

 its vitality for a longer period if replanted upon fresh 

 media every day or two for a time; but if the first geu- 



12 



