Streptococcus Pyogenes is a non-motile, non-liquefying, facultative anaerobic coccus that is about 0.4 to 1u in diameter, that occurs in chains of 10 to 50 members.

Stains with ordinary dyes and by Gram's.

Is found in pus and in erysipelas.

Culture

Best at 370 C. On gelatin plates small, colorless, transparent colonies develop in from twenty-four to fortyeight hours. Are round, granular, with raised edges. Do not liquefy. On agar-agar have very delicate, transparent colonies that do not coalesce.

When it gains entrance into the body it gives rise to more diffuse and more severe suppurations than does the staphylococcus.