and, it is also found in the consideration that evil may lie dormant in every human being.

There is some dread in realizing that through Dr. Jekyll's experiments, he...

...goes against the laws of nature.

Consider, then (in Chapter Four), Mr. Hyde's murder of an elderly and respected member of society, as witnessed by a housemaid from her window.

...London was startled by a crime of singular ferocity, and rendered all the more notable by the high position of the victim... 

Note that it is "a crime of singular ferocity." We are confronted not only with wrong-doing, but an aberrant and wild response of frightening intensity. To witness the event, Stevenson provides a setting that resembles a well-lit stage—

...the early part of the night was cloudless, and the lane...was brilliantly lit by the full moon. 

The moonlight is symbolic of enlightenment—here Mr. Hyde's actions are exposed to the world. The older man is the personification of goodness, not only because of his age (which many cultures view with respect and reverence), but also because of his gentle and innocent nature—much like London at that moment. He is not at all fearful, so he is totally unprepared for the violence that erupts.

Mr. Hyde is presented, an unlikely source of danger...

...advancing to meet [the older gentleman], another and very small gentleman...

In the natural world, the smaller animal is usually seen as less threatening because of its size...not the case with Hyde. This unnatural element also creates a sense of fear—for his actions make little sense in the physical world.

...the older man bowed and [addressed] the other with a very pretty manner of politeness...[with] an innocent and old-world kindness of disposition, yet with something high, too, as of a well-founded self-content.

The goodness of the man reflects the goodness in mankind. On the other hand...

...[the maid] was surprised to recognize...Mr. Hyde...He had in his hand a heavy cane...all of a sudden he broke out in a great flame of anger, stamping with his foot, brandishing the cane, and carrying on...like a madman...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.

Hyde's behavior is chaotic and terrifying, like an animal ("ape-like")—this creates a sense of fear, especially as Hyde is the alter-ego of the very civilized Dr. Jekyll—who (in Chapter Ten) explains:

...in my own person...I learned to recognize the thorough and primitive duality of man...

Jekyll notes that while both sides of this "duality" fight for supremacy, both still exist within him. He feels...

...these polar twins...continuously struggling...

Lastly, Hyde's appearance is also fearful—there was...

...something wrong with his appearance; something displeasing, something down-right detestable.

In all aspects of Hyde, fear and chaos are present—these are the sides of Jekyll that are usually repressed (as with most people) by his control over human nature's darker instincts. That they might escape and have full reign is a frightening prospect.

Dr. Jekyll is afraid of Mr. Hyde because he doesn't know what he might do in that other personality. The story was written in Victorian times when much that is commonplace in modern fiction was absolutely unmentionable then. Mr. Hyde is represented as a totally fiendish, ruthless, sadistic man, but most of what he actually does on his outings is only implied. Buy Dr. Jekyll knows that if he were to lose complete control of his civilized persona, he could commit an endless series of horrible crimes against men, women, and children. He also realizes that if he went on a crime spree in London, it would only be a matter of time before he was arrested and exposed.

The author of "Dr. Jekyll and Mr. Hyde," Robert Louis Stevenson (1850-1894) shows the influence of two American writers, Nathaniel Hawthorne (1804-1864) and Edgar Allan Poe (1809-1849). Hawthorne dramatized the existence of evil in man in stories such as “Young Goodman Brown,” “The Minister’s Black Veil,” and “My Kinsman, Major Molineux,” as well as in his novels, most notably The Scarlet Letter and The House of the Seven Gables. Poe revealed the evil side of man in “The Cask of Amontillado,” “The Tell-Tale Heart,” “The Black Cat,” and other short stories. In “The Strange Case of Dr. Jekyll and Mr. Hyde,” Stevenson seems to be acknowledging the existence of an evil side of human nature but speculating on the possibility of eradicating it. Stevenson is more like Hawthorne than like Poe. Hawthorne usually illustrated the fact that most people try to keep their evil side hidden, whereas Poe wrote in such a way that the  good side, if any, was what was hidden. Hawthorne tended to write in the third person, making it much easier to present his characters from the exterior, from the appearance they made in public. Poe tended to write in the first person, putting the reader right inside the mind of the character who was favoring the evil side of his nature.

There is a lot more evil in human nature than Stevenson, Hawthorne, or Poe ever dared to unveil, but many sins, crimes, perversions, and sadistic actions simply could not be mentioned in those straitlaced times.