To begin with, it is interesting to note that in the novel Jane Eyre' the protagonist - Jane - has been depicted in three facets, which have been externalised as Bertha, Jane and Helen. In the text, Helen represents the ideal Christian ideology of sacrifice and endurance whereas Bertha is representative of many "dark" races, who were believed to have no faith, and of oppression, as a victim of it. In fact, it is taken to be the division of the female psyche - especially of the Victorian female psyche. Bertha and Helen are the extreme components of Jane's conscious - the evil and the good, respectively. They could and in fact, do represent the Victorian sexual ideologies - and in the narrative they function as implied connections to these beliefs. It is due to this polarity of the two characters that they have to be destroyed. Significantly, these characters are metaphorical representation of the different aspects of Jane's personalities and consciousness. It is following only this destruction of the ambiguities of Jane's character that she can develop fully. If the animalistic, violent and demonic Bertha has to be destroyed so does the little saint, the pious, intellectual Helen because they - both of them - restrict Jane's progress.
The resigned Helen - the closest friend and mentor of the child narrator - as we have already mentioned - is removed from the world of the novel by the process of death. Helen is in reality very similar to Jane though she appears far more pious and angelic. She fiercely craves for love, both emotional and physical, just like Jane, craves for it so much that when she does not get it from her father and from others around her she just resigns herself to the world. She starts looking forward to the ultimate union with her "maker", with God where she is assured she would get all the love that had been denied to her in the world. She is not just denied physical fulfilment and led to starvation, but the starvation is of the mind and heart. Also as Elaine Showalter mentions in her critical essay "Charlotte Bronte: Feminine Heroine" - She (Helen) is one extreme aspect of Jane's personalities, for Jane too is tempted by the world of the spirit and the intellect, and has a strong streak of masochism'. Helen's presence is, for Jane, regressive - her piety is overbearing for Jane and thus for her greater benefit - she being the main character - Helen has to be cleaned out of the world of the novel. Also with her death, Jane attains her first victory.
It is worthy of note that certain dispositions attributed to Bertha's character are actually exhibited in Jane's personality. Early on in the novel references to Jane's animalistic tendencies are made. John Reed calls Jane a bad animal' and a mad cat' and most of Jane's behavioural patterns can be credited to the same. In the Victorian era, there were a number of restrictions on the women's movements and behaviours. Such passionate conduct, as revealed by Jane, was definitely not acceptable from a girl child hence her unconventionality, her fury is termed animalistic. It is these animal aspects that are sought to be vanquished in Jane in her spell in the Lowood Institution; Jane's innate, obnoxious' qualities are severely repressed. The lusts of the vile body', in Mr. Brocklehurst's words, are sought to be restrained, their, namely the inmates of Lowood Institution, sexuality are entailed to be inhibited.
By a number of critics, Bertha is Jane's dark double, as we have already mentioned. The...