"I don't understand," Rose said.
"I've got a message from the Daleks. It's probably a trap, but I need to
return to the other universe. It shouldn't take me long, I expect it'll
all be quite straightforward."
"No, I mean I don't understand how you regenerated. The original Doctor
said you couldn't."
"Oh, he doesn't know everything," the Doctor responded airily,
straightening his burgandy waistcoat.
"But this is a form you've had before?"
"Yes, only a bit older. *That's* probably because I'm half-human." He
gave an impish grin, thinking of Donna's reaction to his next comment,
"On my mother's side."
--
Dave
So I looked, and behold, a pale horse.
And the name of him who sat on it was Death.
And the name of the horse was Binky.