Complex sentence: His life and career were dominated by Warburg's Tincture-a a pharmaceutical fever medicine which he invented in 1834 in British Guiana (now Guyana), and which he manufactured, promoted and sold for several decades.
Split into simpler sentences: His life and career were dominated by Warburg's Tincture. This was a pharmaceutical fever medicine which he invented in 1834, in British Guiana (now Guyana) and manufactured, promoted and sold for several decades.