Fig. 28. Bacterial colonies. In the petri dish (above) are two 

 "spreaders." In the corner (lower right) are "pin point" colonies which 

 are very small even when growing on the surface. (From General 

 Bacteriology, D. B. Swingle and W. G. Walter. Copyright 1947, D. Van 

 Nosirand Company, Inc., New York.) 



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