In a book about the duality of human experience, we think it's only fitting that Robert Louis Stevenson uses a kind of split approach when it comes to the writing style of The Strange Case of Dr. Jekyll and Mr. Hyde. On the one hand, he's writing in the Victorian era, for a Victorian audience. What that means for us modern readers is that this book's style comes across as, well, old. To be sure, Stevenson's work is full of antiquated structure and expressions, but it's also very Victorian in another sense, too: it minds its manners.
To the Victorians, manners were everything, and the appearance of being prim and proper counted for a whole heck of a lot. Today, we're far more laid back, but it's important to realize that this book was written for a different time and place. In keeping with the book's theme of the split between the civilized and the uncivilized side of human nature, though, the writing style is at once formal, proper, as well as dark and grimy. Check out an example:
All of a sudden he broke out in a great flame of anger, stamping with his foot, brandishing the cane, and carrying on (as the maid described it) like a madman. The old gentleman took a step back, with the air of one very much surprised and a trifle hurt; and at that Mr. Hyde broke out of all bounds and clubbed him to the earth. And next moment, with ape-like fury, he was trampling his victim under foot and hailing down a storm of blows, under which the bones were audibly shattered and the body jumped upon the roadway. At the horror of these sights and sounds, the maid fainted. (4.1)
Here Stevenson relates the murder of Sir Danvers Carew by Mr. Hyde, as seen through a maid's eyes. Of course, modern readers will find some of the language here a bit out of touch ("a great flame of anger," "the air of one very much surprised"). Of course, what's more shocking is the detailed violence that's wrapped up in this formal little Victorian package. We read that "bones were audibly shattered and the body jumped on the roadway," which is, you know, pretty gruesome stuff.
But really, that choice of writing style—to embed horror inside formal prose—speaks to one of the main themes of the book: the uncivilized side of humanity that lurks within the formal trappings of civilization. Just like the savage Mr. Hyde hides in the formal, civilized Dr. Jekyll, Stevenson uses his writing style to embed chaos within the formal order of this Victorian page-turner. Very clever, Mr. S.