www.hagley.org, the website of the Hagley Museum in Wilmington, DE, is a source for information on patent medicine of the 19th century, and provides the following on Horsford's:
Horsford's Acid Phosphate, circa 1885
Prepared according to the directions of Prof. E. N. Horsford, of Cambridge, Massachusetts, this concoction was suggested for dyspepsia, indigestion, headache, mental and physical exhaustion, nervousness, hysteria, night sweats, consumption, and other ailments. According to their advertising: "This Acid Phosphate…imparts new energy to the system, giving the feeling and sense of increased intellectual and physical power." The use of the baby on the front of the card helped reinforce the "gentleness" of the compound.
Rumford Chemical Works, Providence, Rhode Island