What is the Doctor Who episode when the old lady drinks blood?

The episode title is "Smith and Jones" it is the first episode (not counting specials) of the 3 season (David Tennant's second season).

It is the episode when the Doctor is in a hospital that gets transported to the moon by the Jadoon. The doctor meets Martha Jones who is studying to become a medical doctor and they hunt for the old woman who the jadoon are after.