It is a well recognized fact that arsphenamin, or its analogues, is responsible for a certain number of cases of jaundice that occur in syphilitic patients. This is variously estimated as occurring in from 0.6 to 0.89 per cent, of cases. While jaundice of this origin, in the majority of instances, is not serious, in a certain percentage the process goes on to acute yellow atrophy of the liver with its invariably fatal termination. This fact renders it desirable to devise means for the detection of jaundice in its earliest stages.
It is known that the appearance of jaundice in the skin and mucous membranes and of bile in the urine depends on the concentration of bilirubin in the blood, and that jaundice never appears in the tissues or urine unless the bilirubin reaches and maintains a definite concentration in the blood. Therefore a study of the behavior of the