Two things i had forgotten:
1. that Jekyll was never a "good" man but had always lived a divided life. What the potion does is to isolate- and intensify- the part of him that is enslaved by his "undignified" vices.
2. That Hyde- far from being the the hulking apeman of the movies, is a creepy, white-faced dwarf. There is certain pathos about him. Jekyll's clothes are far too big for him and he has to roll up the trouser legs and sleeves- for all the world like a child playing dress up.