Complex sentence: Across the table sits a fellow vacuum cleaner salesman, a man he'd met earlier called Carter, who offers him whisky--suspicious, Wormold knocks over the glass, which is then drunk by the headwaiter's dachshund, which soon dies.
Split into simpler sentences: Across the table sits a fellow vacuum cleaner salesman he had met earlier, Carter, who offers him whisky. Suspicious, Wormold knocks over the glass, which is then drunk by the headwaiter's dachshund, which soon dies.