Complex sentence: Machen refused; ultimately, however, he agreed to revise the description of the final scene of the book, in order to purge one word that Lane had found to be too explicit; the word was "entrails".
Split into simpler sentences: Machen refused; ultimately, however, he agreed to delete one word, which Lane had found to be too explicit. The word, which occurred in the description of the final scene of the book, was "entrails".