Notes

Dr. Jekyll starts his letter by explaining the two sides of his character: on the one hand, he loves being sober, dignified, and respectable, yet on the other hand he craves pleasure and debauchery.
In his research, he discovers how to split these two natures into two men.
He takes a potion and immediately feels both extreme pleasure and extreme wickedness.
This wickedness is accompanied by a transformation into Mr. Edward Hyde.
He takes the potion and transforms back into Dr. Jekyll.
He therefore does not succeed in creating someone wholly good and someone wholly evil, but rather himself and a wholly evil version of himself.
He makes various arrangements for his new self: a house, a housekeeper, a new will, etc. You need stomping grounds for the evil version of yourself.
Then he goes nuts as Edward Hyde—unfortunately, he gives us no descriptions beyond "wickedness."
His conscience doesn't trouble him, because as Dr. Jekyll, he continues being respectable.
When he knocks over the child as Mr. Hyde, he has to use Dr. Jekyll’s bank account to not get killed by the angry mob. Soon after, he opens a bank account in Mr. Hyde’s name.
Two months before the murder of Sir Danvers Carew, Dr. Jekyll wakes up one morning as Mr. Hyde.
This is disconcerting, to say the least, and Dr. Jekyll begins to feel that he has to make a choice between his two personas.
For the next two months, he lives a respectable life as Dr. Jekyll.
But he longs to become Mr. Hyde again. So one evening, he takes the transformative potion.
Then he beats Sir Danvers Carew to death.
Horrified, he breaks the key to his laboratory and potions, and resumes a sober life as Dr. Jekyll.
But the secret urges remain and one day, sitting in the park, his thoughts grow evil and he transforms into Mr. Hyde.
Away from his potions, and wearing the face of a wanted murderer, Dr. Jekyll sends a note to Dr. Lanyon with specific instructions.
It works: Mr. Hyde transforms back into Dr. Jekyll, but Dr. Lanyon’s friendship is lost forever.
But all is not solved. One day later, Dr. Jekyll is walking in his courtyard and transforms again into Mr. Hyde.
He runs into his laboratory, but it takes a double dose to restore himself to the appearance and personality of Dr. Jekyll.
Six hours later, he again transforms.
Dr. Jekyll rapidly gets sicker and sicker, and Mr. Hyde grows more powerful and more insistent.
Then he runs out of potions. Panicking, he sends his servants all around London looking for a specific kind of salt.
None of the salts work, convincing Dr. Jekyll that there must have been some unknown impurity in the first sample that lent the potion its efficacy.
He ends his letter by saying Dr. Jekyll has most certainly died, and he can only speculate on what will happen to Mr. Hyde. He says he is bringing "the life of that unhappy Henry Jekyll to an end," but we never really know if Jekyll killed himself (and Hyde) before Hyde took over, or whether Hyde, for some unknown reason, killed himself