Tongue.

Food "There's always excitement in the lab when we empty the contents from a type of can that we've not opened before and see a new ingredient for a 1907 Antarctic meal. However, I admit to having been apprehensive about treating a tin of ox tongue." -- Nicola at the Antarctic conservation blog

They're still reconditioning tins for display, which involves opening out the contents. There's a photo of the contents so you can expand your knowledge by finding out what hundred year old tongue looks like. Tasty.