Chapter Nine is the letter Lanyon asked Utterson not to open until both Lanyon and Jekyll have died. Lanyon starts by saying that he received a letter from Dr. Jekyll four days ago and was surprised, because they were not in the habit of corresponding The contents surprised him further. Jekyll’s letter began by addressing Lanyon as one of his oldest friends, and states that, despite their scientific differences, he has always had affection for him and can’t imagine a situation where he would not sacrifice his life to help him. This brings him to his present situation, where he must ask this kind of sacrifice from Lanyon.
The letters and documents of Dr. Jekyll have formed a mass of unanswered questions and unspoken confessions throughout the story, and have maintained the mystery of Hyde’s identity. Now for the first time, light is shed on those mysteries and we begin to unravel all the layers of mystery behind what we have just read. The letter that Lanyon describes begins with a confession, of Jekyll’s affection for Lanyon, but it also includes a kind of deal, of one sacrifice for another, that overshadows the honesty of this confession.
Jekyll goes on to urge Lanyon to postpone all other engagements and to take a carriage directly to his house. Poole has instructions and will be waiting with a locksmith. Jekyll then orders Lanyon to break in to his study and go, alone, into the room and take out a specific drawer, which will have in it some powders, a phial, and a paper book, and take this drawer back to his own home. He should then wait until midnight, at which time he would receive a visit from a man who will present himself as Dr. Jekyll, and he must give him the drawer he has taken from the cabinet. Five minutes later, he will understand everything.
Jekyll lays out these instructions with scientific precision, even timing each one, to make sure that the revelation he hints at happens at exactly the right time, but his plea relies on his faith in Lanyon. This piece of paper, delivered to Lanyon, is all that stands between Jekyll and his fate. The fragility of this document and its importance create an anxious contrast.
Dr. Jekyll adds that he trusts Dr. Lanyon completely, and he asks him to think of his friend, who is in a terrible state, and know that if he agrees to do this task, he will be unburdening him. Jekyll adds a postscript, saying that he has just had another thought that has caused his heart to drop, that the post office may deliver this letter late. In this case, he tells Lanyon to follow the directions and be prepared to receive the visitor at midnight the following day. Jekyll ends by saying that it might be too late by then, and that if Lanyon does not get a call from this visitor, he has seen the last of Henry Jekyll.
This letter shows the voice of a man on the edge. Lanyon represents Jekyll's last hope. Much like the story itself, this document uses its cryptic covering-up of the truth to entice Lanyon and to leave him with no choice but to follow its directions. Jekyll’s refusal to confess continues and the convention of letters and documents that by now makes up a weight of unspoken information serves this end perfectly.
Dr. Lanyon is sure that his old friend has gone mad but is determined to follow his instructions. He goes directly to Jekyll’s place, where he finds Poole and they go, with two tradesman, into the old operating theatre to the door of Jekyll’s study. After they eventually are able to remove the door, Lanyon takes the drawer as ordered. When he gets back to his home, he examines the drawer. He finds the neat packages of powder, some kind of crystalline salt, and a phial of red liquid made from ingredients he can't determine.
The two worlds, of reason and madness, appear before Lanyon and Utterson as the climax of the mystery approaches. All the paraphernalia of the world of science surrounds Lanyon as he explores Jekyll’s study, suggesting that the answer to all this strangeness involves something rational like a chemical reaction, but the errand itself is so unexplained and unusual that Lanyon is sure the doctor has lost his mind.
And finally there is a book of dates and annotations. These notes span many years but have become rarer and rarer closer to the present, with only the occasional, one word remark, exclaiming “total failure!!!” and other such negative statements. Reading all this, Lanyon grows increasingly sure that Dr. Jekyll’s is a case of insanity and he prepares himself with a loaded gun, just in case.
Even this document, which provides the closest account we have to Jekyll’s inner thoughts, is so sparse that it presents more mystery than it reveals. The single word comments cover up hours and hours of unknown experiments.
Lanyon receives a visitor at midnight, and meets him on the porch. The visitor is a small, evil-looking man, who slinks into the house with suspicious glances to the street, and hurries at the sight of a policeman. Now inside, Lanyon has a chance to take a proper look. He remarks that the expression on the man’s face is very disturbing, unnaturally twitchy and yet ill-looking. Lanyon feels what he recognizes as a kind of personal hatred toward the man. The man is dressed in oversize clothes.
By now we know that this visitor is Mr. Hyde, and Lanyon’s description of his evil, stunted appearance brings all his previous deeds to mind. Yet, this creature is an exaggeration of the figure we first met in Enfield’s account – he has become more animal, more convulsive and primal than ever. And note again how Hyde does not just himself seem evil, but inspires a kind of passionate hatred in others.
The visitor is very excitable and demands impatiently whether Lanyon has the drawer. Lanyon maintains his patience and shows the man a chair, and the man apologizes for his rough manner. Lanyon feels slight pity for the man's desperation. He points him to the drawer and the man goes so feverishly to it that Lanyon must tell him to calm down. To this, the man returns a “dreadful smile” and reveals the contents of the drawer to himself with a tragic groan.
Lanyon responds with both pity and repulsion to this figure. The duality that was once between Jekyll and Hyde, now shows itself in Hyde alone – it is symbolized by this phrase “dreadful smile”, the scowl of pleasure and evil at once shows how complex and indefinable the double identity has become.
The visitor asks Lanyon for a graduated glass and Lanyon fetches one for him. Then the man makes a mixture from some of the red liquid and the powder, which soon begins to fume and change color until the visitor seems to be satisfied and turns to Lanyon and makes a speech to him, asking him to seriously consider whether to send him away with this potion or to let him stay and witness the result. He warns Lanyon that he will come into a life-changing kind of knowledge if he agrees, a knowledge that would shock the devil. He reminds Lanyon of the vows he has taken as a medical professional. Lanyon speaks with false calm and tells the man that he has come too far not to see the end of this story.
This is the moment of truth for both Hyde and Lanyon. Lanyon’s life-long beliefs in reason and scientific truths are being threatened and Hyde’s nerves and frenzied actions suggest that this experiment is about to make or break him too. Hyde’s language as he warns Lanyon echoes Lanyon’s criticisms of Jekyll being unscientific and “devilish”. His mention of the devil forebodes that we are about to cross the boundary between science and the supernatural.
The man takes a drink from his concoction and immediately lets out a cry and reels and gasps. What follows is a physical transformation that causes Lanyon to scream with terror. When it is finished, Henry Jekyll stands before him. Lanyon then confesses he cannot write down the awful things Jekyll told him next. He writes that his life has been altered irreversibly; he cannot sleep, and he feels that death is imminent. The last thing he will assure Utterson of is that the man that arrived at his house that night was Mr. Hyde.
Here is the long awaited explanation for every traumatic turn of events. The characters have been so busy looking for rational, logical answers, trying to use their reason, that they have misjudged Jekyll’s interest in mysticism and scientific experimentation. The truth is far more horrific than they suspected, because it is so unpredictable and so contrary to their rational beliefs – this is why Lanyon is so changed by what he sees.