destruction of red blood cells, usually, if you can see a finger or
some other object through the clearing on the plate, you're looking at
Beta hemolysis.
On the right is Alpha hemolysis.....this is the partial destruction of
red blood cells, and often has a greenish hue to it rather than an
actual clearing around the colonies, and while you can see a shaddow
of a finger through it, you won't actually be able to see the finger.
There is one other type of hemolysis....Gamma hemolysis...which is the
term used to indicate a total lack of hemolysis on a plate. (a little
silly when it is just at easy to say no hemolysis, but that is the way
it goes sometimes)
ALso good to remember, that hemolysis is usually a pathogenic
property, or rather a property that many (not all!) pathogenic
organisms posess.
Professor Ammons