'Slave for a slave, woman for a woman' - does that mean that any slave can be killed for a slave killed?

The Quran says > O YOU who have attained to faith! Just retribution is ordained for you > in cases of killing: the free for the free, and the slave for the > slave, and the woman for the woman (Baqarah 178) Does it mean that if a slave is killed, another slave (irrespective of the murderer) is to be killed, and if a woman is killed, then another woman has to be killed in compensation. This is not applied in any Islamic country, so I am sure that I am misreading it. Kindly explain.