Malt Extract "Tonic"

in the pre-Prohibition Era 

 "Malt Extract" was a "patent medicine" type of product, a creation of brewers in the late 1800's-early 1900's  in response to the Temperance Movement. 

Some were thick syrups, taken by the spoonful.  Others were beverages of varying alcoholic content, such as "Ballantine's Ideal Malt Extract", which had 3.25% alcohol (a bit less than today's average "light"  beers).