Admiral Archer's Prized Beagle is probably the label on a cabinet, displaying the poor animal after it's been taxidermied. 100 years is a long time. A exhibited artifect showing the first dog to travel aboard Earth's first warp 5 starship. Some Academy museum curator unaware it's name was Porthos. Riker and Troi didn't seem to know the dog's name either, only that Archer had one.
That probably gets around Scotty's need for something to test, that's biomatter... and what more could happen to the dog? It's already long dead. It just makes his actions seem like a frat boy prank.