Here's an old German advertising cinderella for a
medicine called ferromanganin. At the bottom it
reads "Trademark, Ferromanganin Society, Frankfurt
a(m). M(ain).

Here's some more info on the product, from a 1906 APA list of medicines: Ferromanganin is the name given to a German specialty which is claimed to contain 0.5 percent iron and 0.1 percent of manganese, combined with sugar, in a vehicle composed of 18 percent sugar, 15 percent cognac, some aromatics, and water sufficient to make 100 parts.
Among other things, ferromanganin was supposed to have cured nervousness and hypertension.