Found part of an 1880s Quack Medical Device. Going to go back and see if I can find the rest. Looks better in real life than my scanner can show. “Boyd’s Battery” on one side and “Patent Jan 17, 1879” on the other.
“J.C. Boyd’s Miniature Galvanic Battery that supposedly worked by “galvanic action” due to the “union of metals.” Whereas in a common battery the effect is facilitated by an acid, Boyd’s device needed only “the natural humidity of the skin” to cause a beneficial flow of electricity. This was sufficient to cure nearly any disease by producing “a proper proportion of electricity” in the blood— or so “Professor” Boyd claimed. The device sold for fifty cents and sparked (so to speak) a number of testimonials from customers (printed on the reverse of flyer), all dating from 1879.”