How to get blood off a hardwood floor

Apparently all it takes is some water and a little elbow grease.  Because when my plumber came stumbling up the stairs holding a bloody hand to an even bloodier face, that was the first...but fleeting, I swear... thought I had.  "Aaah blood! Dripping on my brand new floors! Aaaah!"  But then the compassionate, competent, calm nurse side of me came out and I grabbed some towels to help put pressure on his laceration, all the while asking pertinent questions such as: "are you dizzy/light headed?  What's your name?  How many fingers am I holding up? Etc.." He was feeling okay, so I put him in my car and drove him to the emergency room.  A few minutes and a little super glue later he was back to hooking up my sink while I scrubbed out all the blood.  With water from the toilet's water tank.  Now how do I get THAT out of a wood floor?