Complex sentence: Harris's fate prompted William Wilberforce to sponsor a bill which if passed would have abolished the practice, but as one of its proposals would have allowed the anatomical dissection of criminals other than murderers, the House of Lords rejected it.
Split into simpler sentences: Harris's fate prompted William Wilberforce to sponsor a bill which, if passed, would have abolished the practice. But as one of its proposals would have allowed the anatomical dissection of criminals other than murderers, the House of Lords rejected it.