Also present is Ezra Jennings, the assistant of Mr. Candy, who came up with the idea.  
Mrs. Merridew is unwillingly present at the experiment at the climax of this novel.  Also present is Ezra Jennings, the assistant of Mr. Candy, who came up with the idea.  Gabriel Betteredge, who provides the novel's first narrative, is against the laudanum experiment, which though successful, does not reveal that Godfrey Ablewhite was the true culprit.  All ends well with Godfrey's death at the hands of the three Indians and the marriage of Franklin Blake and Rachel Verinder in, FTP, what Wilkie Collins novel centering on the titular jewel?
Mrs. Merridew is unwillingly present at the experiment at the climax of this novel.  
The Moonstone