It is interesting that Jim is a narrator who is not one coming-of-age, but rather one looking backward, and as he does so, he often generates suspense in this adventure story written with the intent of exciting its reader. For example, Jim creates intense interest in the reader in Chapter 7 when he narrates,
Sometimes the isle was thick with savages, with whom we fought; sometimes full of dangerous animals that hunted us; but in all my fancies nothing occurred to me so strange and tragic as our actual adventures.
So, with pirates and such morally ambiguous characters such as Long John Silver, when Jim becomes absent as the narrator, suspense is generated since readers become somewhat anxious about what has happened to Jim. Also, Long John Silver gains as a deceptive character since doctor is equally deceived by him. Moreover, the older voice of Dr. Livesey lends a certain maturity to the narrative, making it more believable, especially as he decides in Chapter 16 to watch and wait rather than launch an attack upon the mutineers because there is no wind and mostly because he has learned that Jim Hawkins has left the ship.
Like Jim, Dr. Livesey is generous and adaptive and practical. Because of these sterling qualities, the doctor makes a good narrator; in addition he helps to move the plot forward, more than Jim could. Also, by Jim's being on the island, he discovers Ben Gunn,who has important knowledge for the others about the treasure.
Abandoning Jim increases the suspense and allows for an alternate point of view.
Narration refers to how a story is told, or the point of view. For most of Treasure Island, young Jim Hawkins is the first person narrator. Dr. Livesey does narrate three chapters of the book. From Chapter 16 to Chapter 18, Jim is with Ben and does not know how to get back to the Hispaniola. From then on, Dr. Livesey takes over the narration. He begins with an acknowledgement of Jim.
It never occurred to us to doubt Jim Hawkins, but we were alarmed for his safety. With the men in the temper they were in, it seemed an even chance if we should see the lad again. (Ch. 16)
It is interesting that Stevenson would choose to abandon Jim for three chapters, but not unheard of. The brief abandonment of his main character with these words just increases the suspense. We worry about Jim.
Dr. Livesey narrates the book when Jim is separated. This allows the reader to get a different, more mature perspective on things, and allows the narrative to continue when Jim is not there. Since he is older, he is clearly going to look at the other characters differently and they will treat him differently. They are respectful and call him, “sir.”
‘If it’s the only course that we can lie, sir, we must even lie it,’ returned the captain. ‘We must keep upstream. You see, sir,’ he went on, ‘if once we dropped to leeward of the landing-place, it’s hard to say where we should get ashore … (Ch. 17)
Also, this allows for us to continue to know what happens when Jim is gone, while also not knowing what is going on with Jim. We are worried about Jim, and the other characters are worried about him. Since we have been handed off to another narrator, Jim may not survive. Therefore he is in real jeopardy, and this creates a great deal of suspense for the reader.
As soon as Jim is free and returns to the story, he takes the reigns as narrator again. It is a smooth handoff. It seems that returning him as narrator is just a matter of practicality. However, Stevenson was taking advantage of Dr. Livesey, and using the fact that he and Jim have an affinity for each other. He also used Jim’s jeopardy to add suspense. Now he can get on with the narration!