Mr. Poole is Dr. Jekyll’s butler and the most senior member of the household staff, having been of service for over twenty years. While he is not necessarily the most dimensional character in terms of personality or character arc, he does serve three specific functions within the framework of the novel. First and foremost, Mr. Poole’s presence allows the plot to advance by bringing Mr. Utterson closer to the scene of Jekyll’s mysterious happenings. He invites the lawyer into Jekyll’s home out of fear for the safety of himself, the rest of the house staff, and his master. Once he does so, Mr. Poole acts as a vehicle through which Stevenson communicates important information to the reader, such as Jekyll’s extreme seclusion, an unfamiliar voice coming from the laboratory, and Hyde’s unwelcome presence in the house. This information invites more theories and possibilities regarding Jekyll’s situation, an effect which speaks to Mr. Poole’s second function in the novel. Since he is so familiar with the mystery’s subject and has insider knowledge of the day-to-day operations of the house, his bewilderment works to heighten the overall confusion and strangeness of the scenario. If Jekyll’s closest contact has no answers, then surely no one else will either. 

The final, more metaphorical function that Mr. Poole serves in the novel is as a gatekeeper between Jekyll and the outside world. On a surface level, he does this in his job as a butler, answering Jekyll’s front door and determining who can and cannot enter the home. Mr. Utterson sees this side of Mr. Poole as he attempts to visit Jekyll at home to no avail. He performs this same function on a metaphorical level, however, as he initially resists disclosing information about Jekyll’s unusual behavior to others. His first interaction with Mr. Utterson, for example, is very straightforward in tone and divulges little. While Mr. Poole protects Jekyll from the outside world early in the novel, he ultimately invites the outside world in by connecting with others on his master’s behalf. The primary example, of course, is the fact that Mr. Poole calls Mr. Utterson to the house and helps him break down the cabinet door, but he also draws other chemists into the mystery by seeking out large quantities of a particular salt and acts as a go-between for Jekyll and Dr. Lanyon. This gatekeeping position ultimately has a powerful influence over the passing of information.