Primary cancers of the liver, extrahepatic bile ducts and pancreas comprise an important group of human neoplasms totalling between 5 and 10 per cent of all carcinomas. The hopeless prognosis of malignant growths in these areas may in part be explained by our clinical inability to recognize these cases at a sufficiently early stage for successful surgical therapy. Amelioration of cancer mortality from these tumors in large measure rests with the family physician and internist, who at present fail to diagnose the disease in two thirds to four fifths of these patients antemortem.1 With the recent revival of interest in cytologic diagnosis of cancer, it seemed possible that the technic of staining exfoliated epithelial cells in duodenal aspirations might contribute information that would be of assistance in the recognition of neoplasms arising from the epithelial surfaces of the exocrine portion of the pancreas, the extrahepatic and intrahepatic radicles of