Beatrix pulls a Rasputin

O.k. so it was a Saturday night, I bring some groceries home, feed the dogs, and then go to change for a very special dinner engagement.
I come downstairs to find Hogan growling over a well chewed chocolate wrapper... Uh oh. That was a 2 ounce chunk of dark Belgian chocolate! What a waste!
I grab a near empty bottle of hydrogen peroxide and a syringe. Hogan gets 2cc's. I watch him for fifteen minutes, as he walked around the kennel room and wagged his tail in confusion at my sudden interest, and then suddenly, all is better. I gave him some pepto and white bread, and then left him to it.
But then I started wondering. Beatrix loves to shop in my grocery bags. It could be possible that she stole the chocolate, and then Hogan took it from her. I studied her carefully, sniffed her breath. Did she eat chocolate or didn't she? So I take 2 cc's of peroxide and down it goes. I wait ten minutes, and then give her the last 2 cc's from the bottle. At this point, I am seriously worrying, I am now out of peroxide and she is hanging on. I hurried to the car, drive to the last open grocery store and buy another big bottle of peroxide. I arrived home to find still no results from Beatrix. I called the vet: up it to 5 ccs, she says, and shake her up a bit. It always works in the end.
So 5cc'ss... a game of fetch... fifteen minutes... 5cc's... I shake her, swing her like a pendulum... fifteen minutes... 5 more cc's... nothing!
By this time I am thinking I have poisoned my dog with peroxide, and I am seriously late for my fancy dinner. Beatrix looked a little nauseated, but just laid on her bed and steadfastly refused to give up the goods. She has a cast iron stomach. I started to think about Rasputin - legendarily poisoned, shot, stabbed and drowned - there is a reason why I gave the name to her son.
So what could I do? She was obviously quietly waiting for me to go away so she could be heartily sick in secret. I made sure she was safe and secure in the kennel room, and just went to dinner. As I left my friends, the last thing I heard them say is that Shereen was offering to supply a round of peroxide shooters to all.
Arriving home, Beatrix had proven my vet's point - they all give it up in the end. I patted poor Beatrix, gave her bread and pepto, and didn't feel hurt when she avoided me.
Oh, and by the way, she hadn't eaten any chocolate.
Wanna know where I looked to find out more about chocolate toxicity?