The Mysterious Mr. Hyde and Dr. Jekyll

As I read the titillating finale of the novel, the clues were finally coming together. At the start of chapter five, Dr. Jekyll told Mr. Utterson that Mr. Hyde would no longer be around. After observing Dr. Jekyll's confidence that Mr. Hyde will not return, I knew that their was more to their relationship that meets the eye. I also found it suspicious that when Jekyll was explaining the letter he received from Mr. Hyde, he seemed oblivious to the fact that the dictation of his will was forced by Hyde. Utterson had to explain that Mr. Hyde planned on murdering Dr. Jekyll. For someone as intelligent and sophisticated as Jekyll, it surprised me that he was so ignorant to the simple concept. When Poole explains to Utterson that he didn't see anyone deliver the letter, it was clear that something was not as it seems. As the story further develops and Dr. Lanyon passes, another clue to the suspicious events of Dr. Jekyll is uncovered. The letter that Utterson retrieves from Lanyon's safe obtains another letter that instructs Utterson not open the letter until Jekyll dies. This provided me with the feeling that Dr. Jekyll isn't who he says he is and is somehow more related to Hyde than I first anticipated. At the very end of the story where Mr. Utterson and Poole breach the laboratory and find Mr. Hyde poisoned in Dr. Jekyll's clothes, I knew the "mad scientist" theme had unravelled. It seems that Dr. Jekyll created a potion in order to transform into Mr. Hyde. My question is why he woud conduct such an experiment? I came to the conclusion that Mr. Jekyll was willing to go beyond his means to perform such a controversial experiment  even though Lanyon warned him not to do so. The story resembles a simple case of a scientist who tries to "play God" and is negatively impacted by his experiment. It is difficult to distinguish whether Dr. Jekyll was mad, or just a scientist performing his duty to discover something new.