Originally Posted by WillCAD

Yeah, but a dog is not a machine. It's a living thing with a nose and a brain, and although it's not at human-level intelligence, a dogs brain IS capable of making finer fuzz-logic distinctions than a machine, which is pretty much binary.

Pup7 will have to chime in on this, because I'm not an expert, but I don't believe that dogs are trained to sniff the chemical precursors of explosives, as the chemical tests in an ETD machine do. Rather, dogs are trained to sniff for whole substances, such as TNT, C4, etc., which have distinct odors. I am doubtful that a dog will alert on lotion with glycerine in it, but the dog WILL alert to nitroglycerine, if trained to do so.

Pup, am I in the ballpark here?