"It was my new-age moms in the 80’s."
A: "My Mother took me to a quack homeopathic doctor, and she actually used this on me. The patient holds the brass handle, and the “Doctor” places a small glass jar with some sort of food or other thing on the pad. The “Doctor” then will then use the other probe and touch the bottom of your bare foot. And somehow they can tell if you are allergic to whatever is on the pad with a reading on the meter."
Same thought here....i realize I am old :-(