If you've ever lived with a cat, you've seen the way they ooze and spill and flow, like a small ambulatory fur puddle. Not only do we think of cats as liquid objects, they smugly seem to know it too.

Some of the gnarliest fluids of the past century have all gone by the same name: “Liquid Death.” The muckrakers of the early 1900s used the term to stand in for nitroglycerin, the highly ...