One of my favorite comics features a genial mutt named Satchel. A recurring theme involves his housemate and nemesis, an arrogant siamese cat named Bucky, who encourages Satchel to eat (or at least swallow) anything conveniently at hand, from roadkill to small electronic appliances. The joke is that Satchel, and by extension all dogs, will give it a try, whatever the consequences.

As is often the case with Cookie, her dietary choices are much more sophisticated than that. There are only a few things that we know are out of the question because they are flat out dangerous for dogs. That donâ...