I noticed a few folks discussing the notion that Jekyll was likely suicidal at the point at which he created and consumed the formula for the first time. I think it is a sound view, and honestly, it feels canon when you read the flashbacks of that moment and the moments that came right before it. Jekyll laying in bed, barely moving, is an obvious one.
I would like to add, and take this how you will, that even though Jekyll would have seemingly been content with whatever happened: death or success, I like to picture the first time he actually saw Hyde in the mirror was- strange as it might've been -a good thing for him.
He wakes up the morning after Hyde's first night out in London.
Maybe he thought it was all a dream. Maybe a drug induced hallucination? Either way, he doesn't expect to see another man staring back at him in the mirror. It spooks him, and Hyde to a lesser extent.
But, then he observes that, yes, this is real. The formula was a success, is a thought that occurs, but a larger thought than that hits him.
He's not alone anymore.
This man, Edward Hyde, though a part of him, though he was him, appeared different from him. He talked to him, responded to him, as though they were in fact two different people.
That's why Hyde was allowed to stick around. He was, for a time, a strange kind of comfort for Jekyll, someone who had, while surrounded by people, felt horribly, destructively, alone.
