Regenerating (fingers, toes, etc)

I recently saw on a documentary about tissue regeneration, but i'm not too sure about the reliability of it. According to them, when you prevent blood clotting, the body is acutally capable of regenerating parts of the body that should not be able to grow back again.

They found out this by accident when a scientist was experimenting to find out the effects of weakening the immune system of white mice. The mice with weakened immune systems were marked by having holes made in their ears so that they would permenantly be different from the other mice.

However, when she returned the next morning, all the mice had whole ears. She couldn't tell the difference between the mice. The mice with weakened immune systems had actually grown back the tissue that has been removed.

So according to the documentry, clotting is a means of blocking up wounds so that infections won't happen within the body, and so that we wont loose too much blood. However, this also means that the body is unable to replace tissue that is beyond the clotted region, making it a permenant handicap.