Dr. Jekyll and Mr. Hyde: Summary: Chapter 10

This last chapter reveals all the previous mysteries and underscores the theme of the whole story, which can be further examined in the Theme Review section. Jekyll begins his auto-biography style narrative explaining that he has found in himself "a profound duplicity of life." Although suppressing it in his early years, as he’s grown older he’s realized that there is two parts to his personality: good and evil. The doctor explains his evil side by saying, "they were the expression, and bore the stamp, of lower elements in my soul."
Jekyll admits that he began experimenting with different chemical solutions until finally he found one which transformed his body to match the evil side of his soul. He acknowledges that this gave him an immense feeling of freedom. He admits, "the thought, in that moment, braced and delighted me like wine... it seemed natural and human... it seemed more express and single, than the imperfect and divided countenance I had been hitherto accustomed to call mine... Edward Hyde...was pure evil." Experimenting again, Dr. Jekyll is reassured when he finds that drinking the solution a second time changes him back to the form of Dr. Jekyll.
Next, Dr. Jekyll explains the violent and cruel acts of Mr. Hyde. Although he does take some responsibility for the atrocities, most of the blame goes to Mr. Hyde. Mr. Hyde, Jekyll explains, doesn’t simply have his own body but also his own independent mind. Once in the body and mind of Hyde, the good side of his soul has no power. This is how he explains the trampling of the child and the murder of the MP.
Unfortunately, Jekyll begins to lose his control of Hyde. One morning, after going to sleep as Jekyll, he awakes as Hyde. The next few days this happens more and more frequently, terrorizing the good side of his soul.
The need for Lanyon to take his medicine drawer arises from the simple fact that Hyde has locked himself out of his laboratory. If he had returned in the person of Hyde, his servants would surely see him and turn him into the police. So he decides to write a letter to Lanyon, telling him what to do.
Although this plan is successful, the ultimate death of Jekyll and Hyde arises when he runs out of the solution which changes his form. Unable to return to the body of Jekyll, the suicidal Hyde gradually eats away at his own body. Soon, the evil of Hyde destroys itself in a mangled mess of blood and guts.