This photograph depicted a subsurface bacterial colony of a non-hemolytic S. pyogenes
growing in a Petri dish filled with trypticase soy agar with 5% sheeps blood, (BAP). A loop of diluted non-hemolytic S. pyogenes
culture was put into the melted agar (50o
C) just before the blood was added to the melted agar, which was then allowed to solidify. It was then incubated at 35o
C for 24 hours in a normal atmosphere. There was only a very small color change in the region surrounding the colony indicating that a narrow zone of red blood cells in the medium had been altered, which meant that these bacteria were "narrow-zone"-hemolytic in nature. Among the streptococcal species this hemolytic activity is found only with "non-hemolytic GAS".