Alimentary, dear Watson

Chip is on the throne, answering his nature’s call, when he decides to call his Baba. “Baba” he says loudly. Baba ignores the calls a few times, but finally goes up to see what his spawn wants. “There is blood in my poo-poo.” Chip tells his Baba calmly. “What?? Blood? Where?” Baba peers down the pot, but his spawn has flushed all evidence of body function.
“Did you see blood in your poo-poo, Chip?” asks Baba.
“Umm, no.”
“Then how do you know there was blood in your poo-poo?”
“There was blood in my nose. I was digging it. There was blood in my snot. I ate it. The blood then went to my tummy and then it went to my poo-poo.”
“But you didn’t see it?”
“No. But it must have been there.”