Congenital obliteration of the bile ducts is a rare disease, but hardly sufficiently uncommon to warrant the report of a single case, unless it presented unusual symptoms, or served as the ground-work for some new conception of the symptomatology, pathogenesis, or pathology of this obscure condition. The excuse offered for this presentation of a case is that the application of a new method of study during life led to a some-what broader point of view of this pathological condition. In the course of a clinical study, carried on at intervals for about six weeks on an infant afflicted with this condition, the duodenal catheter was frequently employed, in order to obtain information as to the excretion into the intestine of bile as well as of the pancreatic ferments. This catheter has been described in connection with a study of spasm and stenosis of the pylorus,1 of icterus neonatorum,