CLAYSON suggested that certain aromatic amines act as bladder carcinogens as a consequence of their metabolic conversion to ortho-hydroxylated derivatives and considerable evidence has accumulated in support of this view (Claysoii, 1962). Amongst the ortho-hydroxylated amines believed to be bladder carcinogens are certain tryptophan metabolites such as, 3-hydroxykynurenine and 3-hydroxyanthranilic acid, and it has been suggested that the urinary excretion of these compounds may cause " spontaneous " bladder tumours in main (Allein, Boyland, Dukes, Horning and Watson, 1957). Abul-Fadl and Khalafallah (1961) have shown an association of ain abnormally high incidence of bladder tumours and a raised level of urinary excretion of 3-hydroxyanthranilic acid in bilharziasis. In view of the possible importance of ortho-aminophenols in the induction of bladder tumours in man, Boyland, Wallace and Williams (1957) suggested that glucosaccharo-l1 4-lactone might be used to inhibit urinary glucuronidase aild thus minimise the formation of free ortho-aminophenols in the bladder. Unfortunately the glucuronides are not the only conjugates, which coul
