Madhu - Kaitabha

Madhu and Kaitabha two demons killed by Vishnu created two beings from his mouth. These were kown as Vishnu and Jishnu and Vishnu (the orignial one ) instructed them to destroy the demons. The being Vishnu killed Kaitabha and Jishnu killed Madhu. But it took a hundred years for the demons to be killed. The fat (meda) from the dead bodies of the demons formed the earth. That is the reason why the earth is known as medini. http://www.gita-society.com/newindex/index.php?html=hindu_puran15&vs=04