puts on a "more commonly grave countenance before the public"
Feels guilt for his hidden desires
"morbid sense of shame"
Commits "to a profound duplicity of life"
duplicity = to be unfaithful/disloyal
implies that Jekyll is disloyal to the christian upper-class society
Science
Jekyll and Lanyon do not agree on their scientific theories, and Dr Lanyon refers to Jekyll's science as "unscientific balderdash"
This means that his theories are nonsense and pollute the field of material medicine with the supernatural and mystical theories that Lanyon and other doctors at the time shunned with resentment.
Jekylls transformation
When Jekyll transforms into Hyde, he feels immense pleasure. The long-term effects of transforming into Hyde cause him to feel shame.
Pleasure
Jekyll gains pleasure from transforming and he is unable to tear himself away from his darker side once the experiments begin.
he says "there was something strange in my sensations, something indescribably new and, from its very novelty, incredibly sweet. I felt younger, lighter, happier in body: within i was conscious of a heady recklessness"
This quote suggests he enjoys the transformations, and he feels released from the heavy restraints of the external society.
Shame
Jekyll writes in chapter 10 how his experiments have failed, and he is ashamed of his failures.
His former self cannot be recreated, because we cannot exist without having both good and evil in us
“Both sides of me [good and evil] were in dead earnest; I was no more myself when I laid aside restraint and plunged in shame, than when I laboured, in the eye of day, at the furtherance of knowledge or the relief of sorrow and suffering".