I would want to answer this question by refering to two aspects of this great unfinished classic by Charles Dickens. Firstly, and most shockingly, the opening chapter introduces the theme of opium and its distorting impact on the human consciousness which is such a major element of Victorian life and society. It is a key element in other such novels as The Picture of Dorian Gray, and it also serves to introduce another key Victorian concept which is that of the double life that Jasper is shown to lead. Note the way that he is introduced in Chapter One:
Shaking from head to foot, the man whose scattered consciousness has thus fantastically pieced itself together, at length rises, supports his trembling frame upon his arms, and looks around. He is in the meanest and closest of small rooms.
It becomes very evident that Jasper has a very different public and private persona, two selves that remain separate. The public, respectable and honourable man that is Edwin's uncle and a valued member of society is very different from the private opium addict that is free to imagine and dream such fantastical and disturbing visions. However, at the same time, it is clear that the fear that Jasper's presence induces in Rosa hints at the way in which Jasper is unable to keep his darker side from intruding into his public life. There are obvious parallels here with works such as The Strange Case of Dr. Jekyll and Mr. Hyde and the Gothic concept of the double.