The Collaborative International Dictionary
Warburg's tincture \War"burg's tinc"ture\ (Pharm.) A preparation containing quinine and many other ingredients, often used in the treatment of malarial affections. It was invented by Dr. Warburg of London.
Wikipedia
Warburg's tincture was a pharmaceutical drug, now obsolete. It was invented in 1834 by Dr Carl Warburg.
Warburg's tincture was well known in the Victorian era as a medicine for fevers, especially tropical fevers, including malaria. It was considered, by some, to be superior to quinine.
Warburg's Tincture was a secret, proprietary remedy. The formula was not published until 1875. Later, it was included in the first edition of Martindale: The Extra Pharmacopoeia. Warburg's Tincture included an array of ingredients, including quinine.