Scar Tissue by Michael Ignatieff Vintage $72 IF death and disease are two of the greatest taboos of the late 20th century, then asking whether a novel about them is a good read comes a close third. ''I do not know how to proceed with the story and I even wonder why it is that I am telling it as a story,'' says the unnamed narrator of Michael Ignatieff's high-brow weepie based on his mother's battle with Alzheimer's disease. But the last thing Ignatieff is asking us to do is to share his doubts. ''Touching'', ''moving'' and ''disturbing'' is the sort of response he is looking for; and it is hard not to suspend judgement over what is largely a piece of cathartic writing whose function is to exercise the pain of bereavement. But it is more of a catalogue than a story. Undoubtedly this is a very sad book. It commemorates the life and death of the narrator's mother, looking back to the vital and talented painter she once was in the halcyon days of his childhood and forward to the broken-bodied, broken-spirited bundle of scrambled brain tissue she later becomes. The book's strength lies in Ignatieff's analysis of the mother's deterioration, documenting the process of what starts out as mere absent-mindedness - like losing spectacles - and escalates into an inability to recognise her family. The more the mother deteriorates, the more she seems to court death. As her memory cells contend with her morale in the race towards oblivion, the narrator begins to see physical disease as a symptom of spiritual anguish and nausea; her accelerated ageing a parody of life itself: ''She rushes through every moment of the day, like someone possessed, like someone saying: let's get this damn thing over with.'' Scar Tissue is in part impelled by bitterness at the insensitive stupidity of the conventional medical mind-set which neglects the spiritual dislocation at the root of brain disease. This is vividly illustrated in a scene where the narrator's family gather in a consultant's office to hear an ambiguous early prognosis of the disease - only to be bluntly asked at the end of the meeting for permission to remove the brain for an autopsy. It is as if in treating bodies, doctors lose sight of the fact that they are attached to people; the soul is merely incidental. Although this is one of the most valuable parts of the book, Ignatieff sounds a false note by apologising for treating the mother ''as if she were a philosophical problem''. If, as he says he believes, physical, neurological and spiritual problems are inextricably bound up with one another, then there is nothing wrong with making them the focus of a novel. But at times all original and insightful elements are drowned out by the blab and gush of self-indulgent adolescent retrospectives. The narrator's mother is relegated to a sub-plot and replaced by Michael Ignatieff, who rather fancies himself as a son and lover with an unresolved Oedipus Complex uttering dreary statements like: ''There were times when I felt she had betrayed me by marrying him [his father].'' This, together with arch little cameos from childhood and scenes of sibling rivalry with his estranged older brother, forms the basis of a very shaky storyline. One of the book's most interesting themes is that there is now little room for tragedy in our antiseptic brave new world. This speaks for itself far more effectively in the course of the book than through Ignatieff's use of the narrator to harangue the reader about the pillaging of the mysteries of the human soul. The stuff of tragedy in the book lies in the logistics of bereavement: what to do with the dead person's clothes; how to deal with their house, not in aesthetic exhibitionism.