Alpha hemolysis (α) is the reduction of the red blood cell hemoglobin to methemoglobin in the medium surrounding the colony. This causes a green or brown discoloration in the medium. The color can be equated with "bruising" the cells. Microscopic inspection of alpha-hemolyzed red blood cells shows that the cell membrane is intact, so it is not, in fact, true lysis. Some text book authors refer to alpha as “partial hemolysis,” which may be confusing to the student. It is most important to not confuse this “partial” or “incomplete” hemolysis with the “weak” or “subtle” lysis of Streptococcus agalactiae or Listeria monocytogenes, as seen above. Beta hemolysis will never include the brown or green discoloration of the cells in the surrounding medium. On prolonged incubation, many alpha hemolytic organisms will begin to appear more clear, but if the surrounding medium contains any shades of brown or green the “hemolysis” is still considered “alpha.”