We now take our narrative from the letter Utterson found in Jekyll’s lab. 

Jekyll begins by detailing his earlier life, stating how his upbringing and nature has constantly been in duality with a darker, more uncouth side. He details how the actions of his private, less respectable self, constantly make his other self guilty. 

When finding an intrigue in science, Jekyll explains that he was motivated to discover the relationship between one’s good and evil natures, and whether they could be separated. Jekyll then goes on to tell how, after rigorous studies, he came across a chemical that may just highlight his theories of the split nature of a single man. 

Creating the solution, he consumed it, knowing the dangers. At first, he experienced severe pain but soon found that it would subside. His body changed, his mind altered to pure temptation, and he became Mr. Hyde. He suggests that the queer small stature of Hyde came about due to that side of his nature being tucked away, hidden for so long. 

The large mirror in Jekyll’s lab was used, according to him, to observe his new self. Whilst others were repulsed by the sight of Hyde, Jekyll was delighted. Jekyll was an aging man, shackled by his reputation and his status, but Hyde was a younger man, not tied down by Jekyll’s social restrictions. 

He furnished Hyde’s desires with his money and did not often despair at the actions of his alter-self, though he did often attempt to make right whatever was made wrong. 

Two months before the Carew murder case, Jekyll was concerned to realise that, whilst asleep, he had turned into Hyde without the help of the potion. Figuring that he was treading dangerously close to being trapped in the body of Hyde forever, Jekyll went about and abstained from the strange elixir. 

However, after two months, he could restrain his need no longer and downed another share of the potion. Hyde, repressed again, erupted as a violent man. Hyde appeared to relish in the beating of Sir Danvers, but this time Jekyll was not ambivalent to the crimes of Hyde, praying for forgiveness. 

Such horror had taught Dr. Jekyll that his succumbing to the temptation was a gross misdeed and he vowed to never do such a thing again. It was during these months of lacking reliance on the chemical that Utterson noted his good health. 

However, Dr. Jekyll soon found himself surrendering to his desires, this time without the formula. However, it appeared that succumbing to the want triggered the transformation when he was in public. Knowing that, as Hyde, he was pursued by the police, he had to go about reverting in some other way, as he was aware that he could not enter his own home. 

He sent word to Lanyon to retrieve the items from the drawer, knowing he would not recognise Hyde. He calculated that, after this unaided transformation in public, he would need to consume a double dose of the elixir every six hours in order to stop the transformation. It was during one of these spontaneous transformations that Dr. Jekyll had to retreat from conversation with Utterson and Enfield. 

Dr Jekyll grows aware of his impending demise as the ingredients for his potion run out. The salt he now uses has little effect and he deduces that the original bulk batch he head procured must have contained something which the new does not. 

Knowing that time is running out for him, he uses the last of his elixir to give himself enough time to write the letter Utterson, stating that, whilst he does not know the fate of Hyde, he knows that Henry Jekyll will cease to exist.