The nice Dr Jekyll faded from Tam’s character and malevolent Mr Hyde began to invade his moods. The cordial, sociable man became temperamental and tetchy. The worst thing about him was that he was unpredictable. One time he responded to an innocent comment at a dinner party with a violent show of temper, smashing all the glasses on the table into the fireplace, then when the fury had passed, he receded into a torpor. To the family, it must have seemed as if a stranger had invaded their father.